This documentation was generated automatically from the AVR Studio part description file `ATmega640.pdf`.

## ANALOG COMPARATOR

### ADCSRB - ADC Control and Status Register B

`sfrb ADCSRB = $7B;`

##### ACME - Analog Comparator Multiplexer Enable

`#define ACME_BIT 6`

`#define ACME_MASK 64`

When this bit is written logic one and the ADC is switched off (ADEN in ADCSR is zero), the ADC multiplexer selects the negative input to the Analog Comparator. When this bit is written logic zero, AIN1 is applied to the negative input of the Analog Comparator. For a detailed description of this bit, see ?Analog Comparator Multiplexed Input? on page 186.

### ACSR - Analog Comparator Control And Status Register

`sfrb ACSR = $30;`

##### ACIS0 - Analog Comparator Interrupt Mode Select bit 0

`#define ACIS0_BIT 0`

`#define ACIS0_MASK 1`

These bits determine which comparator events that trigger the Analog Comparator interrupt.

##### ACIS1 - Analog Comparator Interrupt Mode Select bit 1

`#define ACIS1_BIT 1`

`#define ACIS1_MASK 2`

These bits determine which comparator events that trigger the Analog Comparator interrupt.

##### ACIC - Analog Comparator Input Capture Enable

`#define ACIC_BIT 2`

`#define ACIC_MASK 4`

When written logic one, this bit enables the Input Capture function in Timer/Counter1 to be triggered by the analog comparator. The comparator output is in this case directly connected to the Input Capture front-end logic, making the comparator utilize the noise canceler and edge select features of the Timer/Counter1 Input Capture interrupt. When written logic zero, no connection between the analog comparator and the Input Capture function exists. To make the comparator trigger the Timer/Counter1 Input Capture interrupt, the TICIE1 bit in the Timer Interrupt Mask Register (TIMSK) must be set

##### ACIE - Analog Comparator Interrupt Enable

`#define ACIE_BIT 3`

`#define ACIE_MASK 8`

When the ACIE bit is written logic one and the I-bit in the Status Register is set, the analog comparator interrupt is acti-vated. When written logic zero, the interrupt is disabled.

##### ACI - Analog Comparator Interrupt Flag

`#define ACI_BIT 4`

`#define ACI_MASK 16`

This bit is set by hardware when a comparator output event triggers the interrupt mode defined by ACIS1 and ACIS0. The Analog Comparator Interrupt routine is executed if the ACIE bit is set and the I-bit in SREG is set. ACI is cleared by hard-ware when executing the corresponding interrupt handling vector. Alternatively, ACI is cleared by writing a logic one to the flag.

##### ACO - Analog Compare Output

`#define ACO_BIT 5`

`#define ACO_MASK 32`

The output of the analog comparator is synchronized and then directly connected to ACO. The synchronization introduces a delay of 1-2 clock cycles.

##### ACBG - Analog Comparator Bandgap Select

`#define ACBG_BIT 6`

`#define ACBG_MASK 64`

When this bit is set, a fixed bandgap reference voltage replaces the positive input to the Analog Comparator. When this bit is cleared, AIN0 is applied to the positive input of the Analog Comparator. See ?Internal Voltage Reference? on page 42.

##### ACD - Analog Comparator Disable

`#define ACD_BIT 7`

`#define ACD_MASK 128`

When this bit is written logic one, the power to the analog comparator is switched off. This bit can be set at any time to turn off the analog comparator. This will reduce power consumption in active and idle mode. When changing the ACD bit, the Analog Comparator Interrupt must be disabled by clearing the ACIE bit in ACSR. Otherwise an interrupt can occur when the bit is changed.

### DIDR1 - Digital Input Disable Register 1

`sfrb DIDR1 = $7F;`

##### AIN0D - AIN0 Digital Input Disable

`#define AIN0D_BIT 0`

`#define AIN0D_MASK 1`

When this bit is written logic one,the digital input buffer on the AIN1/0 pin is disabled.The corresponding PIN register bit will always read as zero when this bit is set.When an analog signal is applied to the AIN1/0 pin and the digital input from this pin is not needed,this bit should be written logic one to reduce power consumption in the digital input buffer.

##### AIN1D - AIN1 Digital Input Disable

`#define AIN1D_BIT 1`

`#define AIN1D_MASK 2`

When this bit is written logic one,the digital input buffer on the AIN1/0 pin is disabled.The corresponding PIN register bit will always read as zero when this bit is set.When an analog signal is applied to the AIN1/0 pin and the digital input from this pin is not needed,this bit should be written logic one to reduce power consumption in the digital input buffer.

## USART0

The Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is a highly flexible serial communication device. The main features are: ? Full Duplex Operation (Independent Serial Receive and Transmit Registers) ? Asynchronous or Synchronous Operation ? Master or Slave Clocked Synchronous Operation ? High Resolution Baud Rate Generator ? Supports Serial Frames with 5, 6, 7, 8 or 9 Data Bits and 1 or 2 Stop Bits ? Odd or Even Parity Generation and Parity Check Supported by Hardware ? Data OverRun Detection ? Framing Error Detection ? Noise Filtering Includes False Start Bit Detection and Digital Low Pass Filter ? Three Separate Interrupts on TX Complete, TX Data Register Empty and RX Complete ? Multi-processor Communication Mode ? Double Speed Asynchronous Communica

### UDR0 - USART I/O Data Register

`sfrb UDR0 = $C6;`

##### UDR0-0 - USART I/O Data Register bit 0

`#define UDR0-0_BIT 0`

`#define UDR0-0_MASK 1`

##### UDR0-1 - USART I/O Data Register bit 1

`#define UDR0-1_BIT 1`

`#define UDR0-1_MASK 2`

##### UDR0-2 - USART I/O Data Register bit 2

`#define UDR0-2_BIT 2`

`#define UDR0-2_MASK 4`

##### UDR0-3 - USART I/O Data Register bit 3

`#define UDR0-3_BIT 3`

`#define UDR0-3_MASK 8`

##### UDR0-4 - USART I/O Data Register bit 4

`#define UDR0-4_BIT 4`

`#define UDR0-4_MASK 16`

##### UDR0-5 - USART I/O Data Register bit 5

`#define UDR0-5_BIT 5`

`#define UDR0-5_MASK 32`

##### UDR0-6 - USART I/O Data Register bit 6

`#define UDR0-6_BIT 6`

`#define UDR0-6_MASK 64`

##### UDR0-7 - USART I/O Data Register bit 7

`#define UDR0-7_BIT 7`

`#define UDR0-7_MASK 128`

### UCSR0A - USART Control and Status Register A

`sfrb UCSR0A = $C0;`

##### MPCM0 - Multi-processor Communication Mode

`#define MPCM0_BIT 0`

`#define MPCM0_MASK 1`

This bit enables the Multi-processor Communication Mode. When the MPCM bit is written to one, all the incoming frames received by the USART receiver that do not contain address information will be ignored. The transmitter is unaffected by the MPCM setting. For more detailed information see ?Multi-processor Communication Mode? on page 152.

##### U2X0 - Double the USART transmission speed

`#define U2X0_BIT 1`

`#define U2X0_MASK 2`

This bit only has effect for the asynchronous operation. Write this bit to zero when using synchronous operation. Writing this bit to one will reduce the divisor of the baud rate divider from 16 to 8 effectively doubling the transfer rate for asynchronous communication.

##### UPE0 - Parity Error

`#define UPE0_BIT 2`

`#define UPE0_MASK 4`

This bit is set if the next character in the receive buffer had a Parity Error when received and the parity checking was enabled at that point (UPM1 = 1). This bit is valid until the receive buffer (UDR0) is read. Always set this bit to zero when writing to UCSR0A.

##### DOR0 - Data overRun

`#define DOR0_BIT 3`

`#define DOR0_MASK 8`

This bit is set if an Overrun condition is detected, i.e. when a character already present in the UDRregister is not read before the next character has been shifted into the Receiver Shift register. The OR bit is buffered, which means that it will be set once the valid data still in UDR0E is read. The OR bit is cleared (zero) when data is received and transferred to UDR0.

##### FE0 - Framing Error

`#define FE0_BIT 4`

`#define FE0_MASK 16`

This bit is set if a Framing Error condition is detected, i.e. when the stop bit of an incoming character is zero. The FE bit is cleared when the stop bit of received data is one.

##### UDRE0 - USART Data Register Empty

`#define UDRE0_BIT 5`

`#define UDRE0_MASK 32`

This bit is set (one) when a character written to UDRis transferred to the Transmit shift register. Setting of this bit indicates that the transmitter is ready to receive a new character for transmission. When the UDR0IE bit in UCR is set, the USART Transmit Complete interrupt to be executed as long as UDR0E is set. UDR0E is cleared by writing UDR0. When interrupt-driven data transmittal is used, the USART Data Register Empty Interrupt routine must write UDRin order to clear UDR0E, otherwise a new interrupt will occur once the interrupt routine terminates. UDR0E is set (one) during reset to indicate that the transmitter is re

##### TXC0 - USART Transmitt Complete

`#define TXC0_BIT 6`

`#define TXC0_MASK 64`

This bit is set (one) when the entire character (including the stop bit) in the Transmit Shift register has been shifted out and no new data has been written to UDR0. This flag is especially useful in half-duplex communications interfaces, where a transmitting application must enter receive mode and free the communications bus immediately after completing the transmission. When the TXCIE bit in UCR is set, setting of TXC causes the USART Transmit Complete interrupt to be executed. TXC is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, the TXC bit is cleared (zero) by writing a logical one to the b

##### RXC0 - USART Receive Complete

`#define RXC0_BIT 7`

`#define RXC0_MASK 128`

This bit is set (one) when a received character is transferred from the Receiver Shift register to UDR0. The bit is set regard-less of any detected framing errors. When the RXCIE bit in UCR is set, the USART Receive Complete interrupt will be executed when RXC is set(one). RXC is cleared by reading UDR0. When interrupt-driven data reception is used, the USART Receive Complete Interrupt routine must read UDRin order to clear RXC, otherwise a new interrupt will occur once the interrupt routine terminates.

### UCSR0B - USART Control and Status Register B

`sfrb UCSR0B = $C1;`

##### TXB80 - Transmit Data Bit 8

`#define TXB80_BIT 0`

`#define TXB80_MASK 1`

TXB8 is the 9th data bit in the character to be transmitted when operating with serial frames with 9 data bits. Must be writ-ten before writing the low bits to UDR0.

##### RXB80 - Receive Data Bit 8

`#define RXB80_BIT 1`

`#define RXB80_MASK 2`

RXB8 is the 9th data bit of the received character when operating with serial frames with 9 data bits. Must be read before reading the low bits from UDR0.

##### UCSZ02 - Character Size

`#define UCSZ02_BIT 2`

`#define UCSZ02_MASK 4`

The UCSZ2 bits combined with the UCSZ1:0 bit in UCSR0C sets the number of data bits (character size) in a frame the receiver and transmitter use.

##### TXEN0 - Transmitter Enable

`#define TXEN0_BIT 3`

`#define TXEN0_MASK 8`

Writing this bit to one enables the USART transmitter. The transmitter will override normal port operation for the TxD pin when enabled. The disabling of the transmitter (writing TXEN to zero) will not become effective until ongoing and pending transmissions are completed, i.e. when the transmit shift register and transmit buffer register does not contain data to be transmitted. When disabled, the transmitter will no longer override the TxD port.

##### RXEN0 - Receiver Enable

`#define RXEN0_BIT 4`

`#define RXEN0_MASK 16`

Writing this bit to one enables the USART receiver. The receiver will override normal port operation for the RxD pin when enabled. Disabling the receiver will flush the receive buffer invalidating the FE, DOR and PE flags.

##### UDRIE0 - USART Data register Empty Interrupt Enable

`#define UDRIE0_BIT 5`

`#define UDRIE0_MASK 32`

Writing this bit to one enables interrupt on the UDR0E flag. A Data Register Empty interrupt will be generated only if the UDR0IE bit is written to one, the global interrupt flag in SREG is written to one and the UDR0E bit in UCSR0A is set.

##### TXCIE0 - TX Complete Interrupt Enable

`#define TXCIE0_BIT 6`

`#define TXCIE0_MASK 64`

Writing this bit to one enables interrupt on the TXC flag. A USART Transmit Complete interrupt will be generated only if the TXCIE bit is written to one, the global interrupt flag in SREG is written to one and the TXC bit in UCSR0A is set.

##### RXCIE0 - RX Complete Interrupt Enable

`#define RXCIE0_BIT 7`

`#define RXCIE0_MASK 128`

Writing this bit to one enables interrupt on the RXC flag. A USART Receive Complete interrupt will be generated only if the RXCIE bit is written to one, the global interrupt flag in SREG is written to one and the RXC bit in UCSR0A is set.

### UCSR0C - USART Control and Status Register C

`sfrb UCSR0C = $C2;`

##### UCPOL0 - Clock Polarity

`#define UCPOL0_BIT 0`

`#define UCPOL0_MASK 1`

This bit is used for synchronous mode only. Write this bit to zero when asynchronous mode is used. The UCPOL bit sets the relationship between data output change and data input sample, and the synchronous clock (XCK).

##### UCSZ00 - Character Size

`#define UCSZ00_BIT 1`

`#define UCSZ00_MASK 2`

Character Size: 0 0 0 = 5-bit. 0 0 1 = 6-bit. 0 1 0 = 7 bit. 0 1 1 = 8-bit. 1 1 1 = 9 bit.

##### UCSZ01 - Character Size

`#define UCSZ01_BIT 2`

`#define UCSZ01_MASK 4`

Character Size: 0 0 0 = 5-bit. 0 0 1 = 6-bit. 0 1 0 = 7 bit. 0 1 1 = 8-bit. 1 1 1 = 9 bit.

##### USBS0 - Stop Bit Select

`#define USBS0_BIT 3`

`#define USBS0_MASK 8`

0: 1-bit. 1: 2-bit.

##### UPM00 - Parity Mode Bit 0

`#define UPM00_BIT 4`

`#define UPM00_MASK 16`

This bit enable and set type of parity generation and check. If enabled, the transmitter will automatically generate and send the parity of the transmitted data bits within each frame. The receiver will generate a parity value for the incoming data and compare it to the UPM0 setting. If a mismatch is detected, the PE flag in UCSR0A will be set.

##### UPM01 - Parity Mode Bit 1

`#define UPM01_BIT 5`

`#define UPM01_MASK 32`

This bit enable and set type of parity generation and check. If enabled, the transmitter will automatically generate and send the parity of the transmitted data bits within each frame. The receiver will generate a parity value for the incoming data and compare it to the UPM0 setting. If a mismatch is detected, the PE flag in UCSR0A will be set.

##### UMSEL00 - USART Mode Select

`#define UMSEL00_BIT 6`

`#define UMSEL00_MASK 64`

##### UMSEL01 - USART Mode Select

`#define UMSEL01_BIT 7`

`#define UMSEL01_MASK 128`

### UBRR0H - USART Baud Rate Register High Byte

`sfrb UBRR0H = $C5;`

##### UBRR8 - USART Baud Rate Register bit 8

`#define UBRR8_BIT 0`

`#define UBRR8_MASK 1`

##### UBRR9 - USART Baud Rate Register bit 9

`#define UBRR9_BIT 1`

`#define UBRR9_MASK 2`

##### UBRR10 - USART Baud Rate Register bit 10

`#define UBRR10_BIT 2`

`#define UBRR10_MASK 4`

##### UBRR11 - USART Baud Rate Register bit 11

`#define UBRR11_BIT 3`

`#define UBRR11_MASK 8`

### UBRR0L - USART Baud Rate Register Low Byte

`sfrb UBRR0L = $C4;`

##### UBRR0 - USART Baud Rate Register bit 0

`#define UBRR0_BIT 0`

`#define UBRR0_MASK 1`

##### UBRR1 - USART Baud Rate Register bit 1

`#define UBRR1_BIT 1`

`#define UBRR1_MASK 2`

##### UBRR2 - USART Baud Rate Register bit 2

`#define UBRR2_BIT 2`

`#define UBRR2_MASK 4`

##### UBRR3 - USART Baud Rate Register bit 3

`#define UBRR3_BIT 3`

`#define UBRR3_MASK 8`

##### UBRR4 - USART Baud Rate Register bit 4

`#define UBRR4_BIT 4`

`#define UBRR4_MASK 16`

##### UBRR5 - USART Baud Rate Register bit 5

`#define UBRR5_BIT 5`

`#define UBRR5_MASK 32`

##### UBRR6 - USART Baud Rate Register bit 6

`#define UBRR6_BIT 6`

`#define UBRR6_MASK 64`

##### UBRR7 - USART Baud Rate Register bit 7

`#define UBRR7_BIT 7`

`#define UBRR7_MASK 128`

## TWI

TWI: Simple yet powerful and flexible communications interface, only two bus lines needed. Both master and slave operation supported. Device can operate as transmitter or receiver. 7-bit address space allows up to 128 different slave addresses. Multi-master arbitration support Up to 400 kHz data transfer speed Slew-rate limited output drivers Noise suppression circuitry rejects spikes on bus lines Fully programmable slave address with general call support Address recognition causes wake-up when AVR is in sleep mode The Two-Wire Serial Interface (TWI) is ideally suited to typical microcontroller applications. The TWI protocol allows the systems designer to interconnect up to 128 different devices using only two bidirectional bus lines, one for clock (SCL) andone for data (SDA). The only external hardware needed to implement the bus is a single pull-up resistor for each of the TWI bus lines. All devices connected to the bus have individual addresses, and mechanisms for resolving bus contention are inherent in the TWI pr

### TWAMR - TWI (Slave) Address Mask Register

`sfrb TWAMR = $BD;`

##### TWAM0

`#define TWAM0_BIT 1`

`#define TWAM0_MASK 2`

##### TWAM1

`#define TWAM1_BIT 2`

`#define TWAM1_MASK 4`

##### TWAM2

`#define TWAM2_BIT 3`

`#define TWAM2_MASK 8`

##### TWAM3

`#define TWAM3_BIT 4`

`#define TWAM3_MASK 16`

##### TWAM4

`#define TWAM4_BIT 5`

`#define TWAM4_MASK 32`

##### TWAM5

`#define TWAM5_BIT 6`

`#define TWAM5_MASK 64`

##### TWAM6

`#define TWAM6_BIT 7`

`#define TWAM6_MASK 128`

### TWBR - TWI Bit Rate register

`sfrb TWBR = $B8;`

##### TWBR0

`#define TWBR0_BIT 0`

`#define TWBR0_MASK 1`

##### TWBR1

`#define TWBR1_BIT 1`

`#define TWBR1_MASK 2`

##### TWBR2

`#define TWBR2_BIT 2`

`#define TWBR2_MASK 4`

##### TWBR3

`#define TWBR3_BIT 3`

`#define TWBR3_MASK 8`

##### TWBR4

`#define TWBR4_BIT 4`

`#define TWBR4_MASK 16`

##### TWBR5

`#define TWBR5_BIT 5`

`#define TWBR5_MASK 32`

##### TWBR6

`#define TWBR6_BIT 6`

`#define TWBR6_MASK 64`

##### TWBR7

`#define TWBR7_BIT 7`

`#define TWBR7_MASK 128`

### TWCR - TWI Control Register

`sfrb TWCR = $BC;`

##### TWIE - TWI Interrupt Enable

`#define TWIE_BIT 0`

`#define TWIE_MASK 1`

When this bit is written to one, and the I-bit in SREG is set, the TWI interrupt request will be activated for as long as the TWINT flag is high.

##### TWEN - TWI Enable Bit

`#define TWEN_BIT 2`

`#define TWEN_MASK 4`

The TWEN bit enables TWI operation and activates the TWI interface. When TWEN is written to one, the TWI takes control over the I/O pins connected to the SCL and SDA pins, enabling the slew-rate limiters and spike filters. If this bit is written to zero, the TWI is switched off and all TWI transmissions are terminated, regardless of any ongoing operation.

##### TWWC - TWI Write Collition Flag

`#define TWWC_BIT 3`

`#define TWWC_MASK 8`

The TWWC bit is set when attempting to write to the TWI Data Register - TWDR when TWINT is low. This flag is cleared by writing the TWDR register when TWINT is high.

##### TWSTO - TWI Stop Condition Bit

`#define TWSTO_BIT 4`

`#define TWSTO_MASK 16`

Writing the TWSTO bit to one in master mode will generate a STOP condition on the 2-wire Serial Bus. When the STOP condition is executed on the bus, the TWSTO bit is cleared automatically. In slave mode, setting the TWSTO bit can be used to recover from an error condition. This will not generate a STOP condition, but the TWI returns to a well-defined unaddressed slave mode and releases the SCL and SDA lines to a high impedance state.

##### TWSTA - TWI Start Condition Bit

`#define TWSTA_BIT 5`

`#define TWSTA_MASK 32`

The application writes the TWSTA bit to one when it desires to become a master on the 2-wire Serial Bus. The TWI hard-ware checks if the bus is available, and generates a START condition on the bus if it is free. However, if the bus is not free, the TWI waits until a STOP condition is detected, and then generates a new START condition to claim the bus Master sta-tus. TWSTA is cleared by the TWI hardware when the START condition has been transmitted.

##### TWEA - TWI Enable Acknowledge Bit

`#define TWEA_BIT 6`

`#define TWEA_MASK 64`

The TWEA bit controls the generation of the acknowledge pulse. If the TWEA bit is written to one, the ACK pulse is gener-ated on the TWI bus if the following conditions are met: 1. The device?s own slave address has been received. 2. A general call has been received, while the TWGCE bit in the TWAR is set. 3. A data byte has been received in master receiver or slave receiver mode. By writing the TWEA bit to zero, the device can be virtually disconnected from the 2-wire Serial Bus temporarily. Address recognition can then be resumed by writing the TWEA bit to one again

##### TWINT - TWI Interrupt Flag

`#define TWINT_BIT 7`

`#define TWINT_MASK 128`

This bit is set by hardware when the TWI has finished its current job and expects application software response. If the I-bit in SREG and TWIE in TWCR are set, the MCU will jump to the TWI interrupt vector. While the TWINT flag is set, the SCL low period is stretched. The TWINT flag must be cleared by software by writing a logic one to it. Note that this flag is not automatically cleared by hardware when executing the interrupt routine. Also note that clearing this flag starts the operation of the TWI, so all accesses to the TWI Address Register (TWAR), TWI Status Register (TWSR), and TWI Data Register (TWDR) must be complete before clearing this flag

### TWSR - TWI Status Register

`sfrb TWSR = $B9;`

##### TWPS0 - TWI Prescaler

`#define TWPS0_BIT 0`

`#define TWPS0_MASK 1`

Bits 1..0: These bits can be read and written, and control the bit rate prescaler. See ?Bit Rate Generator Unit? on page 165 for calculating bit rates.

##### TWPS1 - TWI Prescaler

`#define TWPS1_BIT 1`

`#define TWPS1_MASK 2`

Bits 1..0: These bits can be read and written, and control the bit rate prescaler. See ?Bit Rate Generator Unit? on page 165 for calculating bit rates.

##### TWS3 - TWI Status

`#define TWS3_BIT 3`

`#define TWS3_MASK 8`

Bits 7..3: These 5 bits reflect the status of the TWI logic and the 2-Wire Serial Bus. The different status codes are described later in this chapter. Note that the value read from TWSR contains both the 5-bit status value and the 2-bit prescaler value. The application designer should consider masking the prescaler bits to zero when checking the Status bits. This makes status checking independent of prescaler setting. This approach is used in this datasheet, unless otherwise noted. If the prescaler setting remains unchanged in the application, the prescaler bits need not be masked. Instead, bit 1:0 in the values that TWSR is compared to can be modified to match the prescaler setting. This will yield more efficient co

##### TWS4 - TWI Status

`#define TWS4_BIT 4`

`#define TWS4_MASK 16`

Bits 7..3: These 5 bits reflect the status of the TWI logic and the 2-Wire Serial Bus. The different status codes are described later in this chapter. Note that the value read from TWSR contains both the 5-bit status value and the 2-bit prescaler value. The application designer should consider masking the prescaler bits to zero when checking the Status bits. This makes status checking independent of prescaler setting. This approach is used in this datasheet, unless otherwise noted. If the prescaler setting remains unchanged in the application, the prescaler bits need not be masked. Instead, bit 1:0 in the values that TWSR is compared to can be modified to match the prescaler setting. This will yield more efficient co

##### TWS5 - TWI Status

`#define TWS5_BIT 5`

`#define TWS5_MASK 32`

Bits 7..3: These 5 bits reflect the status of the TWI logic and the 2-Wire Serial Bus. The different status codes are described later in this chapter. Note that the value read from TWSR contains both the 5-bit status value and the 2-bit prescaler value. The application designer should consider masking the prescaler bits to zero when checking the Status bits. This makes status checking independent of prescaler setting. This approach is used in this datasheet, unless otherwise noted. If the prescaler setting remains unchanged in the application, the prescaler bits need not be masked. Instead, bit 1:0 in the values that TWSR is compared to can be modified to match the prescaler setting. This will yield more efficient c

##### TWS6 - TWI Status

`#define TWS6_BIT 6`

`#define TWS6_MASK 64`

Bits 7..3: These 5 bits reflect the status of the TWI logic and the 2-Wire Serial Bus. The different status codes are described later in this chapter. Note that the value read from TWSR contains both the 5-bit status value and the 2-bit prescaler value. The application designer should consider masking the prescaler bits to zero when checking the Status bits. This makes status checking independent of prescaler setting. This approach is used in this datasheet, unless otherwise noted. If the prescaler setting remains unchanged in the application, the prescaler bits need not be masked. Instead, bit 1:0 in the values that TWSR is compared to can be modified to match the prescaler setting. This will yield more efficient co

##### TWS7 - TWI Status

`#define TWS7_BIT 7`

`#define TWS7_MASK 128`

Bits 7..3: These 5 bits reflect the status of the TWI logic and the 2-Wire Serial Bus. The different status codes are described later in this chapter. Note that the value read from TWSR contains both the 5-bit status value and the 2-bit prescaler value. The application designer should consider masking the prescaler bits to zero when checking the Status bits. This makes status checking independent of prescaler setting. This approach is used in this datasheet, unless otherwise noted. If the prescaler setting remains unchanged in the application, the prescaler bits need not be masked. Instead, bit 1:0 in the values that TWSR is compared to can be modified to match the prescaler setting. This will yield more efficient c

### TWDR - TWI Data register

`sfrb TWDR = $BB;`

##### TWD0 - TWI Data Register Bit 0

`#define TWD0_BIT 0`

`#define TWD0_MASK 1`

##### TWD1 - TWI Data Register Bit 1

`#define TWD1_BIT 1`

`#define TWD1_MASK 2`

##### TWD2 - TWI Data Register Bit 2

`#define TWD2_BIT 2`

`#define TWD2_MASK 4`

##### TWD3 - TWI Data Register Bit 3

`#define TWD3_BIT 3`

`#define TWD3_MASK 8`

##### TWD4 - TWI Data Register Bit 4

`#define TWD4_BIT 4`

`#define TWD4_MASK 16`

##### TWD5 - TWI Data Register Bit 5

`#define TWD5_BIT 5`

`#define TWD5_MASK 32`

##### TWD6 - TWI Data Register Bit 6

`#define TWD6_BIT 6`

`#define TWD6_MASK 64`

##### TWD7 - TWI Data Register Bit 7

`#define TWD7_BIT 7`

`#define TWD7_MASK 128`

### TWAR - TWI (Slave) Address register

`sfrb TWAR = $BA;`

##### TWGCE - TWI General Call Recognition Enable Bit

`#define TWGCE_BIT 0`

`#define TWGCE_MASK 1`

##### TWA0 - TWI (Slave) Address register Bit 0

`#define TWA0_BIT 1`

`#define TWA0_MASK 2`

##### TWA1 - TWI (Slave) Address register Bit 1

`#define TWA1_BIT 2`

`#define TWA1_MASK 4`

##### TWA2 - TWI (Slave) Address register Bit 2

`#define TWA2_BIT 3`

`#define TWA2_MASK 8`

##### TWA3 - TWI (Slave) Address register Bit 3

`#define TWA3_BIT 4`

`#define TWA3_MASK 16`

##### TWA4 - TWI (Slave) Address register Bit 4

`#define TWA4_BIT 5`

`#define TWA4_MASK 32`

##### TWA5 - TWI (Slave) Address register Bit 5

`#define TWA5_BIT 6`

`#define TWA5_MASK 64`

##### TWA6 - TWI (Slave) Address register Bit 6

`#define TWA6_BIT 7`

`#define TWA6_MASK 128`

## SPI

The Serial Peripheral Interface(SPI) allows high-speed synchronous data transfer between the AT90S4414/8515 and peripheral devices or between several AVR devices. The AT90S4414/8515 SPI features include the following: ? Full-duplex, 3-wire Synchronous Data Transfer ? Master or Slave Operation ? LSB First or MSB First Data Transfer ? Four Programmable Bit Rates ? End of Transmission Interrupt Flag ? Write Collision Flag Protection ? Wakeup from Idle Mode (Slave Mode Only)

### SPCR - SPI Control Register

`sfrb SPCR = $2C;`

##### SPR0 - SPI Clock Rate Select 0

`#define SPR0_BIT 0`

`#define SPR0_MASK 1`

These two bits control the SCK rate of the device configured as a master. SPR1 and SPR0 have no effect on the slave.

##### SPR1 - SPI Clock Rate Select 1

`#define SPR1_BIT 1`

`#define SPR1_MASK 2`

These two bits control the SCK rate of the device configured as a master. SPR1 and SPR0 have no effect on the slave.

##### CPHA - Clock Phase

`#define CPHA_BIT 2`

`#define CPHA_MASK 4`

Refer to Figure 36 or Figure 37 for the functionality of this bit.

##### CPOL - Clock polarity

`#define CPOL_BIT 3`

`#define CPOL_MASK 8`

When this bit is set (one), SCK is high when idle. When CPOL is cleared (zero), SCK is low when idle. Refer to Figure 36 and Figure 37 for additional information.

##### MSTR - Master/Slave Select

`#define MSTR_BIT 4`

`#define MSTR_MASK 16`

This bit selects Master SPI mode when set (one), and Slave SPI mode when cleared (zero). If SS is configured as an input and is driven low while MSTR is set, MSTR will be cleared, and SPIF in SPSR will become set. The user will then have to set MSTR to re-enable SPI master mode.

##### DORD - Data Order

`#define DORD_BIT 5`

`#define DORD_MASK 32`

When the DORD bit is set (one), the LSB of the data word is transmitted first. When the DORD bit is cleared (zero), the MSB of the data word is transmitted first.

##### SPE - SPI Enable

`#define SPE_BIT 6`

`#define SPE_MASK 64`

When the SPE bit is set (one), the SPI is enabled. This bit must be set to enable any SPI operations.

##### SPIE - SPI Interrupt Enable

`#define SPIE_BIT 7`

`#define SPIE_MASK 128`

This bit causes the SPI interrupt to be executed if SPIF bit in the SPSR register is set and the global interrupts are enabled.

### SPSR - SPI Status Register

`sfrb SPSR = $2D;`

##### SPI2X - Double SPI Speed Bit

`#define SPI2X_BIT 0`

`#define SPI2X_MASK 1`

When this bit is written logic one the SPI speed (SCK Frequency)will be doubled when the SPI is in master mode .This means that the minimum SCK period will be 2 CPU clock periods.When the SPI is configured as Slave,the SPI is only guaranteed to work at f osc /4orlower. The SPI interface on the ATmega162 is also used for program memory and EEPROM downloading or uploading.

##### WCOL - Write Collision Flag

`#define WCOL_BIT 6`

`#define WCOL_MASK 64`

The WCOL bit is set if the SPI data register (SPDR) is written during a data transfer. The WCOL bit (and the SPIF bit) are cleared (zero) by first reading the SPI Status Register when WCOL is set (one), and then accessing the SPI Data Register.

##### SPIF - SPI Interrupt Flag

`#define SPIF_BIT 7`

`#define SPIF_MASK 128`

When a serial transfer is complete, the SPIF bit is set (one) and an interrupt is generated if SPIE in SPCR is set (one) and global interrupts are enabled. If SS is an input and is driven low when the SPI is in master mode, this will also set the SPIF flag. SPIF is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, the SPIF bit is cleared by first reading the SPI status register when SPIF is set (one), then accessing the SPI Data Register (SPDR).

### SPDR - SPI Data Register

`sfrb SPDR = $2E;`

##### SPDR0 - SPI Data Register bit 0

`#define SPDR0_BIT 0`

`#define SPDR0_MASK 1`

##### SPDR1 - SPI Data Register bit 1

`#define SPDR1_BIT 1`

`#define SPDR1_MASK 2`

##### SPDR2 - SPI Data Register bit 2

`#define SPDR2_BIT 2`

`#define SPDR2_MASK 4`

##### SPDR3 - SPI Data Register bit 3

`#define SPDR3_BIT 3`

`#define SPDR3_MASK 8`

##### SPDR4 - SPI Data Register bit 4

`#define SPDR4_BIT 4`

`#define SPDR4_MASK 16`

##### SPDR5 - SPI Data Register bit 5

`#define SPDR5_BIT 5`

`#define SPDR5_MASK 32`

##### SPDR6 - SPI Data Register bit 6

`#define SPDR6_BIT 6`

`#define SPDR6_MASK 64`

##### SPDR7 - SPI Data Register bit 7

`#define SPDR7_BIT 7`

`#define SPDR7_MASK 128`

## PORTA

### PORTA - Port A Data Register

`sfrb PORTA = $02;`

##### PORTA0 - Port A Data Register bit 0

`#define PORTA0_BIT 0`

`#define PORTA0_MASK 1`

##### PORTA1 - Port A Data Register bit 1

`#define PORTA1_BIT 1`

`#define PORTA1_MASK 2`

##### PORTA2 - Port A Data Register bit 2

`#define PORTA2_BIT 2`

`#define PORTA2_MASK 4`

##### PORTA3 - Port A Data Register bit 3

`#define PORTA3_BIT 3`

`#define PORTA3_MASK 8`

##### PORTA4 - Port A Data Register bit 4

`#define PORTA4_BIT 4`

`#define PORTA4_MASK 16`

##### PORTA5 - Port A Data Register bit 5

`#define PORTA5_BIT 5`

`#define PORTA5_MASK 32`

##### PORTA6 - Port A Data Register bit 6

`#define PORTA6_BIT 6`

`#define PORTA6_MASK 64`

##### PORTA7 - Port A Data Register bit 7

`#define PORTA7_BIT 7`

`#define PORTA7_MASK 128`

### DDRA - Port A Data Direction Register

`sfrb DDRA = $01;`

##### DDA0 - Data Direction Register, Port A, bit 0

`#define DDA0_BIT 0`

`#define DDA0_MASK 1`

##### DDA1 - Data Direction Register, Port A, bit 1

`#define DDA1_BIT 1`

`#define DDA1_MASK 2`

##### DDA2 - Data Direction Register, Port A, bit 2

`#define DDA2_BIT 2`

`#define DDA2_MASK 4`

##### DDA3 - Data Direction Register, Port A, bit 3

`#define DDA3_BIT 3`

`#define DDA3_MASK 8`

##### DDA4 - Data Direction Register, Port A, bit 4

`#define DDA4_BIT 4`

`#define DDA4_MASK 16`

##### DDA5 - Data Direction Register, Port A, bit 5

`#define DDA5_BIT 5`

`#define DDA5_MASK 32`

##### DDA6 - Data Direction Register, Port A, bit 6

`#define DDA6_BIT 6`

`#define DDA6_MASK 64`

##### DDA7 - Data Direction Register, Port A, bit 7

`#define DDA7_BIT 7`

`#define DDA7_MASK 128`

### PINA - Port A Input Pins

`sfrb PINA = $00;`

##### PINA0 - Input Pins, Port A bit 0

`#define PINA0_BIT 0`

`#define PINA0_MASK 1`

##### PINA1 - Input Pins, Port A bit 1

`#define PINA1_BIT 1`

`#define PINA1_MASK 2`

##### PINA2 - Input Pins, Port A bit 2

`#define PINA2_BIT 2`

`#define PINA2_MASK 4`

##### PINA3 - Input Pins, Port A bit 3

`#define PINA3_BIT 3`

`#define PINA3_MASK 8`

##### PINA4 - Input Pins, Port A bit 4

`#define PINA4_BIT 4`

`#define PINA4_MASK 16`

##### PINA5 - Input Pins, Port A bit 5

`#define PINA5_BIT 5`

`#define PINA5_MASK 32`

##### PINA6 - Input Pins, Port A bit 6

`#define PINA6_BIT 6`

`#define PINA6_MASK 64`

##### PINA7 - Input Pins, Port A bit 7

`#define PINA7_BIT 7`

`#define PINA7_MASK 128`

## PORTB

### PORTB - Port B Data Register

`sfrb PORTB = $05;`

##### PORTB0 - Port B Data Register bit 0

`#define PORTB0_BIT 0`

`#define PORTB0_MASK 1`

##### PORTB1 - Port B Data Register bit 1

`#define PORTB1_BIT 1`

`#define PORTB1_MASK 2`

##### PORTB2 - Port B Data Register bit 2

`#define PORTB2_BIT 2`

`#define PORTB2_MASK 4`

##### PORTB3 - Port B Data Register bit 3

`#define PORTB3_BIT 3`

`#define PORTB3_MASK 8`

##### PORTB4 - Port B Data Register bit 4

`#define PORTB4_BIT 4`

`#define PORTB4_MASK 16`

##### PORTB5 - Port B Data Register bit 5

`#define PORTB5_BIT 5`

`#define PORTB5_MASK 32`

##### PORTB6 - Port B Data Register bit 6

`#define PORTB6_BIT 6`

`#define PORTB6_MASK 64`

##### PORTB7 - Port B Data Register bit 7

`#define PORTB7_BIT 7`

`#define PORTB7_MASK 128`

### DDRB - Port B Data Direction Register

`sfrb DDRB = $04;`

##### DDB0 - Port B Data Direction Register bit 0

`#define DDB0_BIT 0`

`#define DDB0_MASK 1`

##### DDB1 - Port B Data Direction Register bit 1

`#define DDB1_BIT 1`

`#define DDB1_MASK 2`

##### DDB2 - Port B Data Direction Register bit 2

`#define DDB2_BIT 2`

`#define DDB2_MASK 4`

##### DDB3 - Port B Data Direction Register bit 3

`#define DDB3_BIT 3`

`#define DDB3_MASK 8`

##### DDB4 - Port B Data Direction Register bit 4

`#define DDB4_BIT 4`

`#define DDB4_MASK 16`

##### DDB5 - Port B Data Direction Register bit 5

`#define DDB5_BIT 5`

`#define DDB5_MASK 32`

##### DDB6 - Port B Data Direction Register bit 6

`#define DDB6_BIT 6`

`#define DDB6_MASK 64`

##### DDB7 - Port B Data Direction Register bit 7

`#define DDB7_BIT 7`

`#define DDB7_MASK 128`

### PINB - Port B Input Pins

`sfrb PINB = $03;`

##### PINB0 - Port B Input Pins bit 0

`#define PINB0_BIT 0`

`#define PINB0_MASK 1`

##### PINB1 - Port B Input Pins bit 1

`#define PINB1_BIT 1`

`#define PINB1_MASK 2`

##### PINB2 - Port B Input Pins bit 2

`#define PINB2_BIT 2`

`#define PINB2_MASK 4`

##### PINB3 - Port B Input Pins bit 3

`#define PINB3_BIT 3`

`#define PINB3_MASK 8`

##### PINB4 - Port B Input Pins bit 4

`#define PINB4_BIT 4`

`#define PINB4_MASK 16`

##### PINB5 - Port B Input Pins bit 5

`#define PINB5_BIT 5`

`#define PINB5_MASK 32`

##### PINB6 - Port B Input Pins bit 6

`#define PINB6_BIT 6`

`#define PINB6_MASK 64`

##### PINB7 - Port B Input Pins bit 7

`#define PINB7_BIT 7`

`#define PINB7_MASK 128`

## PORTC

### PORTC - Port C Data Register

`sfrb PORTC = $08;`

##### PORTC0 - Port C Data Register bit 0

`#define PORTC0_BIT 0`

`#define PORTC0_MASK 1`

##### PORTC1 - Port C Data Register bit 1

`#define PORTC1_BIT 1`

`#define PORTC1_MASK 2`

##### PORTC2 - Port C Data Register bit 2

`#define PORTC2_BIT 2`

`#define PORTC2_MASK 4`

##### PORTC3 - Port C Data Register bit 3

`#define PORTC3_BIT 3`

`#define PORTC3_MASK 8`

##### PORTC4 - Port C Data Register bit 4

`#define PORTC4_BIT 4`

`#define PORTC4_MASK 16`

##### PORTC5 - Port C Data Register bit 5

`#define PORTC5_BIT 5`

`#define PORTC5_MASK 32`

##### PORTC6 - Port C Data Register bit 6

`#define PORTC6_BIT 6`

`#define PORTC6_MASK 64`

##### PORTC7 - Port C Data Register bit 7

`#define PORTC7_BIT 7`

`#define PORTC7_MASK 128`

### DDRC - Port C Data Direction Register

`sfrb DDRC = $07;`

##### DDC0 - Port C Data Direction Register bit 0

`#define DDC0_BIT 0`

`#define DDC0_MASK 1`

##### DDC1 - Port C Data Direction Register bit 1

`#define DDC1_BIT 1`

`#define DDC1_MASK 2`

##### DDC2 - Port C Data Direction Register bit 2

`#define DDC2_BIT 2`

`#define DDC2_MASK 4`

##### DDC3 - Port C Data Direction Register bit 3

`#define DDC3_BIT 3`

`#define DDC3_MASK 8`

##### DDC4 - Port C Data Direction Register bit 4

`#define DDC4_BIT 4`

`#define DDC4_MASK 16`

##### DDC5 - Port C Data Direction Register bit 5

`#define DDC5_BIT 5`

`#define DDC5_MASK 32`

##### DDC6 - Port C Data Direction Register bit 6

`#define DDC6_BIT 6`

`#define DDC6_MASK 64`

##### DDC7 - Port C Data Direction Register bit 7

`#define DDC7_BIT 7`

`#define DDC7_MASK 128`

### PINC - Port C Input Pins

`sfrb PINC = $06;`

##### PINC0 - Port C Input Pins bit 0

`#define PINC0_BIT 0`

`#define PINC0_MASK 1`

##### PINC1 - Port C Input Pins bit 1

`#define PINC1_BIT 1`

`#define PINC1_MASK 2`

##### PINC2 - Port C Input Pins bit 2

`#define PINC2_BIT 2`

`#define PINC2_MASK 4`

##### PINC3 - Port C Input Pins bit 3

`#define PINC3_BIT 3`

`#define PINC3_MASK 8`

##### PINC4 - Port C Input Pins bit 4

`#define PINC4_BIT 4`

`#define PINC4_MASK 16`

##### PINC5 - Port C Input Pins bit 5

`#define PINC5_BIT 5`

`#define PINC5_MASK 32`

##### PINC6 - Port C Input Pins bit 6

`#define PINC6_BIT 6`

`#define PINC6_MASK 64`

##### PINC7 - Port C Input Pins bit 7

`#define PINC7_BIT 7`

`#define PINC7_MASK 128`

## PORTD

### PORTD - Port D Data Register

`sfrb PORTD = $0B;`

##### PORTD0 - Port D Data Register bit 0

`#define PORTD0_BIT 0`

`#define PORTD0_MASK 1`

##### PORTD1 - Port D Data Register bit 1

`#define PORTD1_BIT 1`

`#define PORTD1_MASK 2`

##### PORTD2 - Port D Data Register bit 2

`#define PORTD2_BIT 2`

`#define PORTD2_MASK 4`

##### PORTD3 - Port D Data Register bit 3

`#define PORTD3_BIT 3`

`#define PORTD3_MASK 8`

##### PORTD4 - Port D Data Register bit 4

`#define PORTD4_BIT 4`

`#define PORTD4_MASK 16`

##### PORTD5 - Port D Data Register bit 5

`#define PORTD5_BIT 5`

`#define PORTD5_MASK 32`

##### PORTD6 - Port D Data Register bit 6

`#define PORTD6_BIT 6`

`#define PORTD6_MASK 64`

##### PORTD7 - Port D Data Register bit 7

`#define PORTD7_BIT 7`

`#define PORTD7_MASK 128`

### DDRD - Port D Data Direction Register

`sfrb DDRD = $0A;`

##### DDD0 - Port D Data Direction Register bit 0

`#define DDD0_BIT 0`

`#define DDD0_MASK 1`

##### DDD1 - Port D Data Direction Register bit 1

`#define DDD1_BIT 1`

`#define DDD1_MASK 2`

##### DDD2 - Port D Data Direction Register bit 2

`#define DDD2_BIT 2`

`#define DDD2_MASK 4`

##### DDD3 - Port D Data Direction Register bit 3

`#define DDD3_BIT 3`

`#define DDD3_MASK 8`

##### DDD4 - Port D Data Direction Register bit 4

`#define DDD4_BIT 4`

`#define DDD4_MASK 16`

##### DDD5 - Port D Data Direction Register bit 5

`#define DDD5_BIT 5`

`#define DDD5_MASK 32`

##### DDD6 - Port D Data Direction Register bit 6

`#define DDD6_BIT 6`

`#define DDD6_MASK 64`

##### DDD7 - Port D Data Direction Register bit 7

`#define DDD7_BIT 7`

`#define DDD7_MASK 128`

### PIND - Port D Input Pins

`sfrb PIND = $09;`

##### PIND0 - Port D Input Pins bit 0

`#define PIND0_BIT 0`

`#define PIND0_MASK 1`

##### PIND1 - Port D Input Pins bit 1

`#define PIND1_BIT 1`

`#define PIND1_MASK 2`

##### PIND2 - Port D Input Pins bit 2

`#define PIND2_BIT 2`

`#define PIND2_MASK 4`

##### PIND3 - Port D Input Pins bit 3

`#define PIND3_BIT 3`

`#define PIND3_MASK 8`

##### PIND4 - Port D Input Pins bit 4

`#define PIND4_BIT 4`

`#define PIND4_MASK 16`

##### PIND5 - Port D Input Pins bit 5

`#define PIND5_BIT 5`

`#define PIND5_MASK 32`

##### PIND6 - Port D Input Pins bit 6

`#define PIND6_BIT 6`

`#define PIND6_MASK 64`

##### PIND7 - Port D Input Pins bit 7

`#define PIND7_BIT 7`

`#define PIND7_MASK 128`

## PORTE

### PORTE - Data Register, Port E

`sfrb PORTE = $0E;`

##### PORTE0

`#define PORTE0_BIT 0`

`#define PORTE0_MASK 1`

##### PORTE1

`#define PORTE1_BIT 1`

`#define PORTE1_MASK 2`

##### PORTE2

`#define PORTE2_BIT 2`

`#define PORTE2_MASK 4`

##### PORTE3

`#define PORTE3_BIT 3`

`#define PORTE3_MASK 8`

##### PORTE4

`#define PORTE4_BIT 4`

`#define PORTE4_MASK 16`

##### PORTE5

`#define PORTE5_BIT 5`

`#define PORTE5_MASK 32`

##### PORTE6

`#define PORTE6_BIT 6`

`#define PORTE6_MASK 64`

##### PORTE7

`#define PORTE7_BIT 7`

`#define PORTE7_MASK 128`

### DDRE - Data Direction Register, Port E

`sfrb DDRE = $0D;`

##### DDE0

`#define DDE0_BIT 0`

`#define DDE0_MASK 1`

##### DDE1

`#define DDE1_BIT 1`

`#define DDE1_MASK 2`

##### DDE2

`#define DDE2_BIT 2`

`#define DDE2_MASK 4`

##### DDE3

`#define DDE3_BIT 3`

`#define DDE3_MASK 8`

##### DDE4

`#define DDE4_BIT 4`

`#define DDE4_MASK 16`

##### DDE5

`#define DDE5_BIT 5`

`#define DDE5_MASK 32`

##### DDE6

`#define DDE6_BIT 6`

`#define DDE6_MASK 64`

##### DDE7

`#define DDE7_BIT 7`

`#define DDE7_MASK 128`

### PINE - Input Pins, Port E

`sfrb PINE = $0C;`

##### PINE0

`#define PINE0_BIT 0`

`#define PINE0_MASK 1`

##### PINE1

`#define PINE1_BIT 1`

`#define PINE1_MASK 2`

##### PINE2

`#define PINE2_BIT 2`

`#define PINE2_MASK 4`

##### PINE3

`#define PINE3_BIT 3`

`#define PINE3_MASK 8`

##### PINE4

`#define PINE4_BIT 4`

`#define PINE4_MASK 16`

##### PINE5

`#define PINE5_BIT 5`

`#define PINE5_MASK 32`

##### PINE6

`#define PINE6_BIT 6`

`#define PINE6_MASK 64`

##### PINE7

`#define PINE7_BIT 7`

`#define PINE7_MASK 128`

## PORTF

### PORTF - Data Register, Port F

`sfrb PORTF = $11;`

##### PORTF0

`#define PORTF0_BIT 0`

`#define PORTF0_MASK 1`

##### PORTF1

`#define PORTF1_BIT 1`

`#define PORTF1_MASK 2`

##### PORTF2

`#define PORTF2_BIT 2`

`#define PORTF2_MASK 4`

##### PORTF3

`#define PORTF3_BIT 3`

`#define PORTF3_MASK 8`

##### PORTF4

`#define PORTF4_BIT 4`

`#define PORTF4_MASK 16`

##### PORTF5

`#define PORTF5_BIT 5`

`#define PORTF5_MASK 32`

##### PORTF6

`#define PORTF6_BIT 6`

`#define PORTF6_MASK 64`

##### PORTF7

`#define PORTF7_BIT 7`

`#define PORTF7_MASK 128`

### DDRF - Data Direction Register, Port F

`sfrb DDRF = $10;`

##### DDF0

`#define DDF0_BIT 0`

`#define DDF0_MASK 1`

##### DDF1

`#define DDF1_BIT 1`

`#define DDF1_MASK 2`

##### DDF2

`#define DDF2_BIT 2`

`#define DDF2_MASK 4`

##### DDF3

`#define DDF3_BIT 3`

`#define DDF3_MASK 8`

##### DDF4

`#define DDF4_BIT 4`

`#define DDF4_MASK 16`

##### DDF5

`#define DDF5_BIT 5`

`#define DDF5_MASK 32`

##### DDF6

`#define DDF6_BIT 6`

`#define DDF6_MASK 64`

##### DDF7

`#define DDF7_BIT 7`

`#define DDF7_MASK 128`

### PINF - Input Pins, Port F

`sfrb PINF = $0F;`

##### PINF0

`#define PINF0_BIT 0`

`#define PINF0_MASK 1`

##### PINF1

`#define PINF1_BIT 1`

`#define PINF1_MASK 2`

##### PINF2

`#define PINF2_BIT 2`

`#define PINF2_MASK 4`

##### PINF3

`#define PINF3_BIT 3`

`#define PINF3_MASK 8`

##### PINF4

`#define PINF4_BIT 4`

`#define PINF4_MASK 16`

##### PINF5

`#define PINF5_BIT 5`

`#define PINF5_MASK 32`

##### PINF6

`#define PINF6_BIT 6`

`#define PINF6_MASK 64`

##### PINF7

`#define PINF7_BIT 7`

`#define PINF7_MASK 128`

## PORTG

### PORTG - Data Register, Port G

`sfrb PORTG = $14;`

##### PORTG0

`#define PORTG0_BIT 0`

`#define PORTG0_MASK 1`

##### PORTG1

`#define PORTG1_BIT 1`

`#define PORTG1_MASK 2`

##### PORTG2

`#define PORTG2_BIT 2`

`#define PORTG2_MASK 4`

##### PORTG3

`#define PORTG3_BIT 3`

`#define PORTG3_MASK 8`

##### PORTG4

`#define PORTG4_BIT 4`

`#define PORTG4_MASK 16`

##### PORTG5

`#define PORTG5_BIT 5`

`#define PORTG5_MASK 32`

### DDRG -

`sfrb DDRG = $13;`

##### DDG0

`#define DDG0_BIT 0`

`#define DDG0_MASK 1`

##### DDG1

`#define DDG1_BIT 1`

`#define DDG1_MASK 2`

##### DDG2

`#define DDG2_BIT 2`

`#define DDG2_MASK 4`

##### DDG3

`#define DDG3_BIT 3`

`#define DDG3_MASK 8`

##### DDG4

`#define DDG4_BIT 4`

`#define DDG4_MASK 16`

##### DDG5

`#define DDG5_BIT 5`

`#define DDG5_MASK 32`

### PING - Input Pins, Port G

`sfrb PING = $12;`

##### PING0

`#define PING0_BIT 0`

`#define PING0_MASK 1`

##### PING1

`#define PING1_BIT 1`

`#define PING1_MASK 2`

##### PING2

`#define PING2_BIT 2`

`#define PING2_MASK 4`

##### PING3

`#define PING3_BIT 3`

`#define PING3_MASK 8`

##### PING4

`#define PING4_BIT 4`

`#define PING4_MASK 16`

##### PING5

`#define PING5_BIT 5`

`#define PING5_MASK 32`

## PORTH

### PORTH - PORT H Data Register

`sfrb PORTH = $102;`

##### PORTH0 - PORT H Data Register bit 0

`#define PORTH0_BIT 0`

`#define PORTH0_MASK 1`

##### PORTH1 - PORT H Data Register bit 1

`#define PORTH1_BIT 1`

`#define PORTH1_MASK 2`

##### PORTH2 - PORT H Data Register bit 2

`#define PORTH2_BIT 2`

`#define PORTH2_MASK 4`

##### PORTH3 - PORT H Data Register bit 3

`#define PORTH3_BIT 3`

`#define PORTH3_MASK 8`

##### PORTH4 - PORT H Data Register bit 4

`#define PORTH4_BIT 4`

`#define PORTH4_MASK 16`

##### PORTH5 - PORT H Data Register bit 5

`#define PORTH5_BIT 5`

`#define PORTH5_MASK 32`

##### PORTH6 - PORT H Data Register bit 6

`#define PORTH6_BIT 6`

`#define PORTH6_MASK 64`

##### PORTH7 - PORT H Data Register bit 7

`#define PORTH7_BIT 7`

`#define PORTH7_MASK 128`

### DDRH - PORT H Data Direction Register

`sfrb DDRH = $101;`

##### DDH0 - PORT H Data Direction Register bit 0

`#define DDH0_BIT 0`

`#define DDH0_MASK 1`

##### DDH1 - PORT H Data Direction Register bit 1

`#define DDH1_BIT 1`

`#define DDH1_MASK 2`

##### DDH2 - PORT H Data Direction Register bit 2

`#define DDH2_BIT 2`

`#define DDH2_MASK 4`

##### DDH3 - PORT H Data Direction Register bit 3

`#define DDH3_BIT 3`

`#define DDH3_MASK 8`

##### DDH4 - PORT H Data Direction Register bit 4

`#define DDH4_BIT 4`

`#define DDH4_MASK 16`

##### DDH5 - PORT H Data Direction Register bit 5

`#define DDH5_BIT 5`

`#define DDH5_MASK 32`

##### DDH6 - PORT H Data Direction Register bit 6

`#define DDH6_BIT 6`

`#define DDH6_MASK 64`

##### DDH7 - PORT H Data Direction Register bit 7

`#define DDH7_BIT 7`

`#define DDH7_MASK 128`

### PINH - PORT H Input Pins

`sfrb PINH = $100;`

##### PINH0 - PORT H Input Pins bit 0

`#define PINH0_BIT 0`

`#define PINH0_MASK 1`

##### PINH1 - PORT H Input Pins bit 1

`#define PINH1_BIT 1`

`#define PINH1_MASK 2`

##### PINH2 - PORT H Input Pins bit 2

`#define PINH2_BIT 2`

`#define PINH2_MASK 4`

##### PINH3 - PORT H Input Pins bit 3

`#define PINH3_BIT 3`

`#define PINH3_MASK 8`

##### PINH4 - PORT H Input Pins bit 4

`#define PINH4_BIT 4`

`#define PINH4_MASK 16`

##### PINH5 - PORT H Input Pins bit 5

`#define PINH5_BIT 5`

`#define PINH5_MASK 32`

##### PINH6 - PORT H Input Pins bit 6

`#define PINH6_BIT 6`

`#define PINH6_MASK 64`

##### PINH7 - PORT H Input Pins bit 7

`#define PINH7_BIT 7`

`#define PINH7_MASK 128`

## PORTJ

### PORTJ - PORT J Data Register

`sfrb PORTJ = $105;`

##### PORTJ0 - PORT J Data Register bit 0

`#define PORTJ0_BIT 0`

`#define PORTJ0_MASK 1`

##### PORTJ1 - PORT J Data Register bit 1

`#define PORTJ1_BIT 1`

`#define PORTJ1_MASK 2`

##### PORTJ2 - PORT J Data Register bit 2

`#define PORTJ2_BIT 2`

`#define PORTJ2_MASK 4`

##### PORTJ3 - PORT J Data Register bit 3

`#define PORTJ3_BIT 3`

`#define PORTJ3_MASK 8`

##### PORTJ4 - PORT J Data Register bit 4

`#define PORTJ4_BIT 4`

`#define PORTJ4_MASK 16`

##### PORTJ5 - PORT J Data Register bit 5

`#define PORTJ5_BIT 5`

`#define PORTJ5_MASK 32`

##### PORTJ6 - PORT J Data Register bit 6

`#define PORTJ6_BIT 6`

`#define PORTJ6_MASK 64`

##### PORTJ7 - PORT J Data Register bit 7

`#define PORTJ7_BIT 7`

`#define PORTJ7_MASK 128`

### DDRJ - PORT J Data Direction Register

`sfrb DDRJ = $104;`

##### DDJ0 - PORT J Data Direction Register bit 0

`#define DDJ0_BIT 0`

`#define DDJ0_MASK 1`

##### DDJ1 - PORT J Data Direction Register bit 1

`#define DDJ1_BIT 1`

`#define DDJ1_MASK 2`

##### DDJ2 - PORT J Data Direction Register bit 2

`#define DDJ2_BIT 2`

`#define DDJ2_MASK 4`

##### DDJ3 - PORT J Data Direction Register bit 3

`#define DDJ3_BIT 3`

`#define DDJ3_MASK 8`

##### DDJ4 - PORT J Data Direction Register bit 4

`#define DDJ4_BIT 4`

`#define DDJ4_MASK 16`

##### DDJ5 - PORT J Data Direction Register bit 5

`#define DDJ5_BIT 5`

`#define DDJ5_MASK 32`

##### DDJ6 - PORT J Data Direction Register bit 6

`#define DDJ6_BIT 6`

`#define DDJ6_MASK 64`

##### DDJ7 - PORT J Data Direction Register bit 7

`#define DDJ7_BIT 7`

`#define DDJ7_MASK 128`

### PINJ - PORT J Input Pins

`sfrb PINJ = $103;`

##### PINJ0 - PORT J Input Pins bit 0

`#define PINJ0_BIT 0`

`#define PINJ0_MASK 1`

##### PINJ1 - PORT J Input Pins bit 1

`#define PINJ1_BIT 1`

`#define PINJ1_MASK 2`

##### PINJ2 - PORT J Input Pins bit 2

`#define PINJ2_BIT 2`

`#define PINJ2_MASK 4`

##### PINJ3 - PORT J Input Pins bit 3

`#define PINJ3_BIT 3`

`#define PINJ3_MASK 8`

##### PINJ4 - PORT J Input Pins bit 4

`#define PINJ4_BIT 4`

`#define PINJ4_MASK 16`

##### PINJ5 - PORT J Input Pins bit 5

`#define PINJ5_BIT 5`

`#define PINJ5_MASK 32`

##### PINJ6 - PORT J Input Pins bit 6

`#define PINJ6_BIT 6`

`#define PINJ6_MASK 64`

##### PINJ7 - PORT J Input Pins bit 7

`#define PINJ7_BIT 7`

`#define PINJ7_MASK 128`

## PORTK

### PORTK - PORT K Data Register

`sfrb PORTK = $108;`

##### PORTK0 - PORT K Data Register bit 0

`#define PORTK0_BIT 0`

`#define PORTK0_MASK 1`

##### PORTK1 - PORT K Data Register bit 1

`#define PORTK1_BIT 1`

`#define PORTK1_MASK 2`

##### PORTK2 - PORT K Data Register bit 2

`#define PORTK2_BIT 2`

`#define PORTK2_MASK 4`

##### PORTK3 - PORT K Data Register bit 3

`#define PORTK3_BIT 3`

`#define PORTK3_MASK 8`

##### PORTK4 - PORT K Data Register bit 4

`#define PORTK4_BIT 4`

`#define PORTK4_MASK 16`

##### PORTK5 - PORT K Data Register bit 5

`#define PORTK5_BIT 5`

`#define PORTK5_MASK 32`

##### PORTK6 - PORT K Data Register bit 6

`#define PORTK6_BIT 6`

`#define PORTK6_MASK 64`

##### PORTK7 - PORT K Data Register bit 7

`#define PORTK7_BIT 7`

`#define PORTK7_MASK 128`

### DDRK - PORT K Data Direction Register

`sfrb DDRK = $107;`

##### DDK0 - PORT K Data Direction Register bit 0

`#define DDK0_BIT 0`

`#define DDK0_MASK 1`

##### DDK1 - PORT K Data Direction Register bit 1

`#define DDK1_BIT 1`

`#define DDK1_MASK 2`

##### DDK2 - PORT K Data Direction Register bit 2

`#define DDK2_BIT 2`

`#define DDK2_MASK 4`

##### DDK3 - PORT K Data Direction Register bit 3

`#define DDK3_BIT 3`

`#define DDK3_MASK 8`

##### DDK4 - PORT K Data Direction Register bit 4

`#define DDK4_BIT 4`

`#define DDK4_MASK 16`

##### DDK5 - PORT K Data Direction Register bit 5

`#define DDK5_BIT 5`

`#define DDK5_MASK 32`

##### DDK6 - PORT K Data Direction Register bit 6

`#define DDK6_BIT 6`

`#define DDK6_MASK 64`

##### DDK7 - PORT K Data Direction Register bit 7

`#define DDK7_BIT 7`

`#define DDK7_MASK 128`

### PINK - PORT K Input Pins

`sfrb PINK = $106;`

##### PINK0 - PORT K Input Pins bit 0

`#define PINK0_BIT 0`

`#define PINK0_MASK 1`

##### PINK1 - PORT K Input Pins bit 1

`#define PINK1_BIT 1`

`#define PINK1_MASK 2`

##### PINK2 - PORT K Input Pins bit 2

`#define PINK2_BIT 2`

`#define PINK2_MASK 4`

##### PINK3 - PORT K Input Pins bit 3

`#define PINK3_BIT 3`

`#define PINK3_MASK 8`

##### PINK4 - PORT K Input Pins bit 4

`#define PINK4_BIT 4`

`#define PINK4_MASK 16`

##### PINK5 - PORT K Input Pins bit 5

`#define PINK5_BIT 5`

`#define PINK5_MASK 32`

##### PINK6 - PORT K Input Pins bit 6

`#define PINK6_BIT 6`

`#define PINK6_MASK 64`

##### PINK7 - PORT K Input Pins bit 7

`#define PINK7_BIT 7`

`#define PINK7_MASK 128`

## PORTL

### PORTL - PORT L Data Register

`sfrb PORTL = $10B;`

##### PORTL0 - PORT L Data Register bit 0

`#define PORTL0_BIT 0`

`#define PORTL0_MASK 1`

##### PORTL1 - PORT L Data Register bit 1

`#define PORTL1_BIT 1`

`#define PORTL1_MASK 2`

##### PORTL2 - PORT L Data Register bit 2

`#define PORTL2_BIT 2`

`#define PORTL2_MASK 4`

##### PORTL3 - PORT L Data Register bit 3

`#define PORTL3_BIT 3`

`#define PORTL3_MASK 8`

##### PORTL4 - PORT L Data Register bit 4

`#define PORTL4_BIT 4`

`#define PORTL4_MASK 16`

##### PORTL5 - PORT L Data Register bit 5

`#define PORTL5_BIT 5`

`#define PORTL5_MASK 32`

##### PORTL6 - PORT L Data Register bit 6

`#define PORTL6_BIT 6`

`#define PORTL6_MASK 64`

##### PORTL7 - PORT L Data Register bit 7

`#define PORTL7_BIT 7`

`#define PORTL7_MASK 128`

### DDRL - PORT L Data Direction Register

`sfrb DDRL = $10A;`

##### DDL0 - PORT L Data Direction Register bit 0

`#define DDL0_BIT 0`

`#define DDL0_MASK 1`

##### DDL1 - PORT L Data Direction Register bit 1

`#define DDL1_BIT 1`

`#define DDL1_MASK 2`

##### DDL2 - PORT L Data Direction Register bit 2

`#define DDL2_BIT 2`

`#define DDL2_MASK 4`

##### DDL3 - PORT L Data Direction Register bit 3

`#define DDL3_BIT 3`

`#define DDL3_MASK 8`

##### DDL4 - PORT L Data Direction Register bit 4

`#define DDL4_BIT 4`

`#define DDL4_MASK 16`

##### DDL5 - PORT L Data Direction Register bit 5

`#define DDL5_BIT 5`

`#define DDL5_MASK 32`

##### DDL6 - PORT L Data Direction Register bit 6

`#define DDL6_BIT 6`

`#define DDL6_MASK 64`

##### DDL7 - PORT L Data Direction Register bit 7

`#define DDL7_BIT 7`

`#define DDL7_MASK 128`

### PINL - PORT L Input Pins

`sfrb PINL = $109;`

##### PINL0 - PORT L Input Pins bit 0

`#define PINL0_BIT 0`

`#define PINL0_MASK 1`

##### PINL1 - PORT L Input Pins bit 1

`#define PINL1_BIT 1`

`#define PINL1_MASK 2`

##### PINL2 - PORT L Input Pins bit 2

`#define PINL2_BIT 2`

`#define PINL2_MASK 4`

##### PINL3 - PORT L Input Pins bit 3

`#define PINL3_BIT 3`

`#define PINL3_MASK 8`

##### PINL4 - PORT L Input Pins bit 4

`#define PINL4_BIT 4`

`#define PINL4_MASK 16`

##### PINL5 - PORT L Input Pins bit 5

`#define PINL5_BIT 5`

`#define PINL5_MASK 32`

##### PINL6 - PORT L Input Pins bit 6

`#define PINL6_BIT 6`

`#define PINL6_MASK 64`

##### PINL7 - PORT L Input Pins bit 7

`#define PINL7_BIT 7`

`#define PINL7_MASK 128`

## TIMER COUNTER 0

### OCR0B - Timer/Counter0 Output Compare Register

`sfrb OCR0B = $28;`

##### OCR0B_0

`#define OCR0B_0_BIT 0`

`#define OCR0B_0_MASK 1`

##### OCR0B_1

`#define OCR0B_1_BIT 1`

`#define OCR0B_1_MASK 2`

##### OCR0B_2

`#define OCR0B_2_BIT 2`

`#define OCR0B_2_MASK 4`

##### OCR0B_3

`#define OCR0B_3_BIT 3`

`#define OCR0B_3_MASK 8`

##### OCR0B_4

`#define OCR0B_4_BIT 4`

`#define OCR0B_4_MASK 16`

##### OCR0B_5

`#define OCR0B_5_BIT 5`

`#define OCR0B_5_MASK 32`

##### OCR0B_6

`#define OCR0B_6_BIT 6`

`#define OCR0B_6_MASK 64`

##### OCR0B_7

`#define OCR0B_7_BIT 7`

`#define OCR0B_7_MASK 128`

### OCR0A - Timer/Counter0 Output Compare Register

`sfrb OCR0A = $27;`

##### OCROA_0

`#define OCROA_0_BIT 0`

`#define OCROA_0_MASK 1`

##### OCROA_1

`#define OCROA_1_BIT 1`

`#define OCROA_1_MASK 2`

##### OCROA_2

`#define OCROA_2_BIT 2`

`#define OCROA_2_MASK 4`

##### OCROA_3

`#define OCROA_3_BIT 3`

`#define OCROA_3_MASK 8`

##### OCROA_4

`#define OCROA_4_BIT 4`

`#define OCROA_4_MASK 16`

##### OCROA_5

`#define OCROA_5_BIT 5`

`#define OCROA_5_MASK 32`

##### OCROA_6

`#define OCROA_6_BIT 6`

`#define OCROA_6_MASK 64`

##### OCROA_7

`#define OCROA_7_BIT 7`

`#define OCROA_7_MASK 128`

### TCNT0 - Timer/Counter0

`sfrb TCNT0 = $26;`

##### TCNT0_0

`#define TCNT0_0_BIT 0`

`#define TCNT0_0_MASK 1`

##### TCNT0_1

`#define TCNT0_1_BIT 1`

`#define TCNT0_1_MASK 2`

##### TCNT0_2

`#define TCNT0_2_BIT 2`

`#define TCNT0_2_MASK 4`

##### TCNT0_3

`#define TCNT0_3_BIT 3`

`#define TCNT0_3_MASK 8`

##### TCNT0_4

`#define TCNT0_4_BIT 4`

`#define TCNT0_4_MASK 16`

##### TCNT0_5

`#define TCNT0_5_BIT 5`

`#define TCNT0_5_MASK 32`

##### TCNT0_6

`#define TCNT0_6_BIT 6`

`#define TCNT0_6_MASK 64`

##### TCNT0_7

`#define TCNT0_7_BIT 7`

`#define TCNT0_7_MASK 128`

### TCCR0B - Timer/Counter Control Register B

`sfrb TCCR0B = $25;`

##### CS00 - Clock Select

`#define CS00_BIT 0`

`#define CS00_MASK 1`

##### CS01 - Clock Select

`#define CS01_BIT 1`

`#define CS01_MASK 2`

##### CS02 - Clock Select

`#define CS02_BIT 2`

`#define CS02_MASK 4`

##### WGM02

`#define WGM02_BIT 3`

`#define WGM02_MASK 8`

##### FOC0B - Force Output Compare B

`#define FOC0B_BIT 6`

`#define FOC0B_MASK 64`

##### FOC0A - Force Output Compare A

`#define FOC0A_BIT 7`

`#define FOC0A_MASK 128`

### TCCR0A - Timer/Counter Control Register A

`sfrb TCCR0A = $24;`

##### WGM00 - Waveform Generation Mode

`#define WGM00_BIT 0`

`#define WGM00_MASK 1`

##### WGM01 - Waveform Generation Mode

`#define WGM01_BIT 1`

`#define WGM01_MASK 2`

##### COM0B0 - Compare Output Mode, Fast PWm

`#define COM0B0_BIT 4`

`#define COM0B0_MASK 16`

##### COM0B1 - Compare Output Mode, Fast PWm

`#define COM0B1_BIT 5`

`#define COM0B1_MASK 32`

##### COM0A0 - Compare Output Mode, Phase Correct PWM Mode

`#define COM0A0_BIT 6`

`#define COM0A0_MASK 64`

##### COM0A1 - Compare Output Mode, Phase Correct PWM Mode

`#define COM0A1_BIT 7`

`#define COM0A1_MASK 128`

### TIMSK0 - Timer/Counter0 Interrupt Mask Register

`sfrb TIMSK0 = $6E;`

##### TOIE0 - Timer/Counter0 Overflow Interrupt Enable

`#define TOIE0_BIT 0`

`#define TOIE0_MASK 1`

##### OCIE0A - Timer/Counter0 Output Compare Match A Interrupt Enable

`#define OCIE0A_BIT 1`

`#define OCIE0A_MASK 2`

##### OCIE0B - Timer/Counter0 Output Compare Match B Interrupt Enable

`#define OCIE0B_BIT 2`

`#define OCIE0B_MASK 4`

### TIFR0 - Timer/Counter0 Interrupt Flag register

`sfrb TIFR0 = $15;`

##### TOV0 - Timer/Counter0 Overflow Flag

`#define TOV0_BIT 0`

`#define TOV0_MASK 1`

##### OCF0A - Timer/Counter0 Output Compare Flag 0A

`#define OCF0A_BIT 1`

`#define OCF0A_MASK 2`

##### OCF0B - Timer/Counter0 Output Compare Flag 0B

`#define OCF0B_BIT 2`

`#define OCF0B_MASK 4`

### GTCCR - General Timer/Counter Control Register

`sfrb GTCCR = $23;`

##### PSRSYNC - Prescaler Reset Timer/Counter1 and Timer/Counter0

`#define PSRSYNC_BIT 0`

`#define PSRSYNC_MASK 1`

When this bit is one, Timer/Counter1 and Timer/Counter0 prescaler will be Reset. This bit is normally cleared immediately by hardware, except if the TSM bit is set. Note that Timer/Counter1 and Timer/Counter0 share the same prescaler and a reset of this prescaler will affect both timers.

##### TSM - Timer/Counter Synchronization Mode

`#define TSM_BIT 7`

`#define TSM_MASK 128`

Writing the TSM bit to one activates the Timer/Counter Synchronization mode. In this mode, the value that is written to the PSR2 and PSR10 bits is kept, hence keeping the corresponding prescaler reset signals asserted. This ensures that the corresponding Timer/Counters are halted and can be configured to the same value without the risk of one of them advancing during configuration. When the TSM bit is written to zero, the PSR2 and PSR10 bits are cleared by hardware, and the Timer/Counters start counting simultaneousl

## TIMER COUNTER 2

The 8-bit Timer/Counter2 can select clock source from CK, prescaled CK, or external crystal input TOSC1. It can also be stopped as described in the section ?Timer/Counter2 Control Register - TCCR2?. The status flags (overflow and compare match) are found in the Timer/Counter Interrupt Flag Register - TIFR. Control signals are found in the Timer/Counter Control Register TCCR2. The interrupt enable/disable settings are found in ?The Timer/Counter Interrupt Mask Register - TIMSK?. When Timer/Counter2 is externally clocked, the external signal is synchronized with the oscillator frequency of the CPU. To assure proper sampling of the external clock, the minimum time between two external clock transitions must be at least one internal CPU clock period. The external clock signal is sampled on the rising edge of the internal CPU clock. This module features a high resolution and a high accuracy usage with the lower prescaling opportunities. Similarly, the high prescaling opportunities make this unit useful for lower speed functions or exact timing functions with infrequent actions. Timer/Counter2 can also be used as an 8-bit Pulse Width Modulator. In this mode, Timer/Counter2 and the output compare register serve as a glitch-free, stand-alone PWM with centered puls

### TIMSK2 - Timer/Counter Interrupt Mask register

`sfrb TIMSK2 = $70;`

##### TOIE2 - Timer/Counter2 Overflow Interrupt Enable

`#define TOIE2_BIT 0`

`#define TOIE2_MASK 1`

When the TOIE2 bit is written to one and the I-bit in the Status Register is set (one), the Timer/Counter2 Overflow interrupt is enabled. The corresponding interrupt is executed if an overflow in Timer/Counter2 occurs, i.e., when the TOV2 bit is set in the Timer/Counter2 Interrupt Flag Register ? TIFR2.

##### OCIE2A - Timer/Counter2 Output Compare Match A Interrupt Enable

`#define OCIE2A_BIT 1`

`#define OCIE2A_MASK 2`

When the OCIE2A bit is written to one and the I-bit in the Status Register is set (one), the Timer/Counter2 Compare Match A interrupt is enabled. The corresponding interrupt is executed if a compare match in Timer/Counter2 occurs, i.e., when the OCF2A bit is set in the Timer/Counter 2 Interrupt Flag Register ? TIFR2.

##### OCIE2B - Timer/Counter2 Output Compare Match B Interrupt Enable

`#define OCIE2B_BIT 2`

`#define OCIE2B_MASK 4`

When the OCIE2B bit is written to one and the I-bit in the Status Register is set (one), the Timer/Counter2 Compare Match B interrupt is enabled. The corresponding interrupt is executed if a compare match in Timer/Counter2 occurs, i.e., when the OCF2B bit is set in the Timer/Counter 2 Interrupt Flag Register ? TIFR2.

### TIFR2 - Timer/Counter Interrupt Flag Register

`sfrb TIFR2 = $17;`

##### TOV2 - Timer/Counter2 Overflow Flag

`#define TOV2_BIT 0`

`#define TOV2_MASK 1`

The TOV2 bit is set (one) when an overflow occurs in Timer/Counter2. TOV2 is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, TOV2 is cleared by writing a logic one to the flag. When the SREG I-bit, TOIE2A (Timer/Counter2 Overflow Interrupt Enable), and TOV2 are set (one), the Timer/Counter2 Overflow interrupt is executed. In PWM mode, this bit is set when Timer/Counter2 changes counting direction at 0x00.

##### OCF2A - Output Compare Flag 2A

`#define OCF2A_BIT 1`

`#define OCF2A_MASK 2`

The OCF2A bit is set (one) when a compare match occurs between the Timer/Counter2 and the data in OCR2A ? Output Compare Register2. OCF2A is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, OCF2A is cleared by writing a logic one to the flag. When the I-bit in SREG, OCIE2A (Timer/Counter2 Compare match Interrupt Enable), and OCF2A are set (one), the Timer/Counter2 Compare match Interrupt is executed.

##### OCF2B - Output Compare Flag 2B

`#define OCF2B_BIT 2`

`#define OCF2B_MASK 4`

The OCF2B bit is set (one) when a compare match occurs between the Timer/Counter2 and the data in OCR2B ? Output Compare Register2. OCF2B is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, OCF2B is cleared by writing a logic one to the flag. When the I-bit in SREG, OCIE2B (Timer/Counter2 Compare match Interrupt Enable), and OCF2B are set (one), the Timer/Counter2 Compare match Interrupt is executed.

### TCCR2A - Timer/Counter2 Control Register A

`sfrb TCCR2A = $B0;`

##### WGM20 - Waveform Genration Mode

`#define WGM20_BIT 0`

`#define WGM20_MASK 1`

These bits control the counting sequence of the counter,the source for hte maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter), Clear Timer on Compare match (CTC)mode,and two types of Pulse Width Modulation (PWM)modes. Please refer to the manual for more information.

##### WGM21 - Waveform Genration Mode

`#define WGM21_BIT 1`

`#define WGM21_MASK 2`

These bits control the counting sequence of the counter,the source for hte maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter), Clear Timer on Compare match (CTC)mode,and two types of Pulse Width Modulation (PWM)modes. Please refer to the manual for more information.

##### COM2B0 - Compare Output Mode bit 0

`#define COM2B0_BIT 4`

`#define COM2B0_MASK 16`

The COM21 and COM20 control bits determine any output pin action following a compare match in Timer/Counter2. Output pin actions affect pin PD7(OC2). This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. (COM21:COM20) description: (0:0) = Timer/Counter disconnected from output pin OC2. (0:1) = Toggle the OC2 output line. (1:0) = Clear the OC2 output line (to zero). (1:1) = Set the OC2 output line (to one). Note: In PWM mode, these bits have a different functio

##### COM2B1 - Compare Output Mode bit 1

`#define COM2B1_BIT 5`

`#define COM2B1_MASK 32`

The COM21 and COM20 control bits determine any output pin action following a compare match in Timer/Counter2. Output pin actions affect pin PD7(OC2). This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. (COM21:COM20) description: (0:0) = Timer/Counter disconnected from output pin OC2. (0:1) = Toggle the OC2 output line. (1:0) = Clear the OC2 output line (to zero). (1:1) = Set the OC2 output line (to one). Note: In PWM mode, these bits have a different function

##### COM2A0 - Compare Output Mode bit 1

`#define COM2A0_BIT 6`

`#define COM2A0_MASK 64`

The COM21 and COM20 control bits determine any output pin action following a compare match in Timer/Counter2. Output pin actions affect pin PD7(OC2). This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. (COM21:COM20) description: (0:0) = Timer/Counter disconnected from output pin OC2. (0:1) = Toggle the OC2 output line. (1:0) = Clear the OC2 output line (to zero). (1:1) = Set the OC2 output line (to one). Note: In PWM mode, these bits have a different function

##### COM2A1 - Compare Output Mode bit 1

`#define COM2A1_BIT 7`

`#define COM2A1_MASK 128`

The COM21 and COM20 control bits determine any output pin action following a compare match in Timer/Counter2. Output pin actions affect pin PD7(OC2). This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. (COM21:COM20) description: (0:0) = Timer/Counter disconnected from output pin OC2. (0:1) = Toggle the OC2 output line. (1:0) = Clear the OC2 output line (to zero). (1:1) = Set the OC2 output line (to one). Note: In PWM mode, these bits have a different function

### TCCR2B - Timer/Counter2 Control Register B

`sfrb TCCR2B = $B1;`

##### CS20 - Clock Select bit 0

`#define CS20_BIT 0`

`#define CS20_MASK 1`

The Clock Select bits 2,1, and 0 define the prescaling source of Timer/Counter2. (CS22:CS21:CS20) Description. (0:0:0) Timer/Counter2 is stopped. (0:0:1) PCK2. (0:1:0) PCK2/8. (0:1:1) PCK2/32. (1:0:0) PCK2/64. (1:0:1) PCK2/128. (1:1:0) PCK2/256. (1:1:1) PCK2/1024. The Stop condition provides a Timer Enable/Disable function. The prescaled modes are scaled directly from the PCK2 clock.

##### CS21 - Clock Select bit 1

`#define CS21_BIT 1`

`#define CS21_MASK 2`

The Clock Select bits 2,1, and 0 define the prescaling source of Timer/Counter2. (CS22:CS21:CS20) Description. (0:0:0) Timer/Counter2 is stopped. (0:0:1) PCK2. (0:1:0) PCK2/8. (0:1:1) PCK2/32. (1:0:0) PCK2/64. (1:0:1) PCK2/128. (1:1:0) PCK2/256. (1:1:1) PCK2/1024. The Stop condition provides a Timer Enable/Disable function. The prescaled modes are scaled directly from the PCK2 clock.

##### CS22 - Clock Select bit 2

`#define CS22_BIT 2`

`#define CS22_MASK 4`

The Clock Select bits 2,1, and 0 define the prescaling source of Timer/Counter2. (CS22:CS21:CS20) Description. (0:0:0) Timer/Counter2 is stopped. (0:0:1) PCK2. (0:1:0) PCK2/8. (0:1:1) PCK2/32. (1:0:0) PCK2/64. (1:0:1) PCK2/128. (1:1:0) PCK2/256. (1:1:1) PCK2/1024. The Stop condition provides a Timer Enable/Disable function. The prescaled modes are scaled directly from the PCK2 clock.

##### WGM22 - Waveform Generation Mode

`#define WGM22_BIT 3`

`#define WGM22_MASK 8`

These bits control the counting sequence of the counter,the source for hte maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter), Clear Timer on Compare match (CTC)mode,and two types of Pulse Width Modulation (PWM)modes. Please refer to the manual for more information.

##### FOC2B - Force Output Compare B

`#define FOC2B_BIT 6`

`#define FOC2B_MASK 64`

Writing a logical one to this bit, forces a change in the compare match output pin PD7 (OC2) according to the values already set in COM21 and COM20. If the COM21 and COM20 bits are written in the same cycle as FOC2, the new settings will not take effect until next compare match or forced output compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM21 and COM20 happens as if a Compare Match had occurred, but no interrupt is generated, and the Timer/Counter will not be cleared even if CTC2 is set. The corresponding I/O pin must be set as an output pin for the FOC2 bit to have effect on the pin. The FOC2 bit will always be read as zero. Setting the FOC2 bit has no effect in PWM mode

##### FOC2A - Force Output Compare A

`#define FOC2A_BIT 7`

`#define FOC2A_MASK 128`

Writing a logical one to this bit, forces a change in the compare match output pin PD7 (OC2) according to the values already set in COM21 and COM20. If the COM21 and COM20 bits are written in the same cycle as FOC2, the new settings will not take effect until next compare match or forced output compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM21 and COM20 happens as if a Compare Match had occurred, but no interrupt is generated, and the Timer/Counter will not be cleared even if CTC2 is set. The corresponding I/O pin must be set as an output pin for the FOC2 bit to have effect on the pin. The FOC2 bit will always be read as zero. Setting the FOC2 bit has no effect in PWM mode

### TCNT2 - Timer/Counter2

`sfrb TCNT2 = $B2;`

##### TCNT2-0 - Timer/Counter 2 bit 0

`#define TCNT2-0_BIT 0`

`#define TCNT2-0_MASK 1`

##### TCNT2-1 - Timer/Counter 2 bit 1

`#define TCNT2-1_BIT 1`

`#define TCNT2-1_MASK 2`

##### TCNT2-2 - Timer/Counter 2 bit 2

`#define TCNT2-2_BIT 2`

`#define TCNT2-2_MASK 4`

##### TCNT2-3 - Timer/Counter 2 bit 3

`#define TCNT2-3_BIT 3`

`#define TCNT2-3_MASK 8`

##### TCNT2-4 - Timer/Counter 2 bit 4

`#define TCNT2-4_BIT 4`

`#define TCNT2-4_MASK 16`

##### TCNT2-5 - Timer/Counter 2 bit 5

`#define TCNT2-5_BIT 5`

`#define TCNT2-5_MASK 32`

##### TCNT2-6 - Timer/Counter 2 bit 6

`#define TCNT2-6_BIT 6`

`#define TCNT2-6_MASK 64`

##### TCNT2-7 - Timer/Counter 2 bit 7

`#define TCNT2-7_BIT 7`

`#define TCNT2-7_MASK 128`

### OCR2B - Timer/Counter2 Output Compare Register B

`sfrb OCR2B = $B4;`

##### OCR2-0 - Timer/Counter2 Output Compare Register Bit 0

`#define OCR2-0_BIT 0`

`#define OCR2-0_MASK 1`

##### OCR2-1 - Timer/Counter2 Output Compare Register Bit 1

`#define OCR2-1_BIT 1`

`#define OCR2-1_MASK 2`

##### OCR2-2 - Timer/Counter2 Output Compare Register Bit 2

`#define OCR2-2_BIT 2`

`#define OCR2-2_MASK 4`

##### OCR2-3 - Timer/Counter2 Output Compare Register Bit 3

`#define OCR2-3_BIT 3`

`#define OCR2-3_MASK 8`

##### OCR2-4 - Timer/Counter2 Output Compare Register Bit 4

`#define OCR2-4_BIT 4`

`#define OCR2-4_MASK 16`

##### OCR2-5 - Timer/Counter2 Output Compare Register Bit 5

`#define OCR2-5_BIT 5`

`#define OCR2-5_MASK 32`

##### OCR2-6 - Timer/Counter2 Output Compare Register Bit 6

`#define OCR2-6_BIT 6`

`#define OCR2-6_MASK 64`

##### OCR2-7 - Timer/Counter2 Output Compare Register Bit 7

`#define OCR2-7_BIT 7`

`#define OCR2-7_MASK 128`

### OCR2A - Timer/Counter2 Output Compare Register A

`sfrb OCR2A = $B3;`

##### OCR2-0 - Timer/Counter2 Output Compare Register Bit 0

`#define OCR2-0_BIT 0`

`#define OCR2-0_MASK 1`

##### OCR2-1 - Timer/Counter2 Output Compare Register Bit 1

`#define OCR2-1_BIT 1`

`#define OCR2-1_MASK 2`

##### OCR2-2 - Timer/Counter2 Output Compare Register Bit 2

`#define OCR2-2_BIT 2`

`#define OCR2-2_MASK 4`

##### OCR2-3 - Timer/Counter2 Output Compare Register Bit 3

`#define OCR2-3_BIT 3`

`#define OCR2-3_MASK 8`

##### OCR2-4 - Timer/Counter2 Output Compare Register Bit 4

`#define OCR2-4_BIT 4`

`#define OCR2-4_MASK 16`

##### OCR2-5 - Timer/Counter2 Output Compare Register Bit 5

`#define OCR2-5_BIT 5`

`#define OCR2-5_MASK 32`

##### OCR2-6 - Timer/Counter2 Output Compare Register Bit 6

`#define OCR2-6_BIT 6`

`#define OCR2-6_MASK 64`

##### OCR2-7 - Timer/Counter2 Output Compare Register Bit 7

`#define OCR2-7_BIT 7`

`#define OCR2-7_MASK 128`

### ASSR - Asynchronous Status Register

`sfrb ASSR = $B6;`

##### TCR2BUB - Timer/Counter Control Register2 Update Busy

`#define TCR2BUB_BIT 0`

`#define TCR2BUB_MASK 1`

When Timer/Counter2 operates asynchronously and TCCR2B is written, this bit becomes set. When TCCR2B has been updated from the temporary storage register, this bit is cleared by hardware. A logical zero in this bit indicates that TCCR2B is ready to be updated with a new value.

##### TCR2AUB - Timer/Counter Control Register2 Update Busy

`#define TCR2AUB_BIT 1`

`#define TCR2AUB_MASK 2`

When Timer/Counter2 operates asynchronously and TCCR2A is written, this bit becomes set. When TCCR2A has been updated from the temporary storage register, this bit is cleared by hardware. A logical zero in this bit indicates that TCCR2A is ready to be updated with a new value.

##### OCR2BUB - Output Compare Register 2 Update Busy

`#define OCR2BUB_BIT 2`

`#define OCR2BUB_MASK 4`

When Timer/Counter2 operates asynchronously and OCR2B is written, this bit becomes set. When OCR2B has been updated from the temporary storage register, this bit is cleared by hardware. A logical zero in this bit indicates that OCR2B is ready to be updated with a new value.

##### OCR2AUB - Output Compare Register2 Update Busy

`#define OCR2AUB_BIT 3`

`#define OCR2AUB_MASK 8`

When Timer/Counter2 operates asynchronously and OCR2A is written, this bit becomes set. When OCR2A has been updated from the temporary storage register, this bit is cleared by hardware. A logical zero in this bit indicates that OCR2A is ready to be updated with a new value.

##### TCN2UB - Timer/Counter2 Update Busy

`#define TCN2UB_BIT 4`

`#define TCN2UB_MASK 16`

When Timer/Counter2 operates asynchronously and TCNT2 is written, this bit becomes set. When TCNT2 has been updated from the temporary storage register, this bit is cleared by hardware. A logical zero in this bit indicates that TCNT2 is ready to be updated with a new value.

##### AS2 - Asynchronous Timer/Counter2

`#define AS2_BIT 5`

`#define AS2_MASK 32`

When AS2 is written to zero, Timer/Counter2 is clocked from the I/O clock, clkI/O. When AS2 is written to one, Timer/Counter2 is clocked from a crystal Oscillator connected to the Timer Oscillator 1 (TOSC1) pin. When the value of AS2 is changed, the contents of TCNT2, OCR2A, OCR2B, TCCR2A and TCCR2B might be corrupted.

##### EXCLK - Enable External Clock Input

`#define EXCLK_BIT 6`

`#define EXCLK_MASK 64`

When EXCLK is written to one, and asynchronous clock is selected, the external clock input buffer is enabled and an external clock can be input on Timer Oscillator 1 (TOSC1) pin instead of a 32 kHz crystal. Writing to EXCLK should be done before asynchronous operation is selected. Note that the crystal Oscillator will only run when this bit is zero.

### GTCCR - General Timer Counter Control register

`sfrb GTCCR = $23;`

##### PSRASY - Prescaler Reset Timer/Counter2

`#define PSRASY_BIT 1`

`#define PSRASY_MASK 2`

When this bit is one, the Timer/Counter2 prescaler will be reset. This bit is normally cleared immediately by hardware. If the bit is written when Timer/Counter2 is operating in asynchronous mode, the bit will remain one until the prescaler has been reset. The bit will not be cleared by hardware if the TSM bit is set. Refer to the description of the ?Bit 7 ? TSM: Timer/Counter Synchronization Mode? on page 107 for a description of the Timer/Counter Synchronization mode.

##### TSM - Timer/Counter Synchronization Mode

`#define TSM_BIT 7`

`#define TSM_MASK 128`

## WATCHDOG

### WDTCSR - Watchdog Timer Control Register

`sfrb WDTCSR = $60;`

##### WDP0 - Watch Dog Timer Prescaler bit 0

`#define WDP0_BIT 0`

`#define WDP0_MASK 1`

##### WDP1 - Watch Dog Timer Prescaler bit 1

`#define WDP1_BIT 1`

`#define WDP1_MASK 2`

##### WDP2 - Watch Dog Timer Prescaler bit 2

`#define WDP2_BIT 2`

`#define WDP2_MASK 4`

##### WDE - Watch Dog Enable

`#define WDE_BIT 3`

`#define WDE_MASK 8`

When the WDE is set (one) the Watchdog Timer is enabled, and if the WDE is cleared (zero) the Watchdog Timer function is disabled. WDE can only be cleared if the WDTOE bit is set(one). To disable an enabled watchdog timer, the following procedure must be followed: 1. In the same operation, write a logical one to WDTOE and WDE. A logical one must be written to WDE even though it is set to one before the disable operation starts. 2. Within the next four clock cycles, write a logical 0 to WDE. This disables the watchdog

##### WDCE - Watchdog Change Enable

`#define WDCE_BIT 4`

`#define WDCE_MASK 16`

##### WDP3 - Watchdog Timer Prescaler Bit 3

`#define WDP3_BIT 5`

`#define WDP3_MASK 32`

##### WDIE - Watchdog Timeout Interrupt Enable

`#define WDIE_BIT 6`

`#define WDIE_MASK 64`

##### WDIF - Watchdog Timeout Interrupt Flag

`#define WDIF_BIT 7`

`#define WDIF_MASK 128`

## USART1

The Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is a highly flexible serial communication device. The main features are: ? Full Duplex Operation (Independent Serial Receive and Transmit Registers) ? Asynchronous or Synchronous Operation ? Master or Slave Clocked Synchronous Operation ? High Resolution Baud Rate Generator ? Supports Serial Frames with 5, 6, 7, 8 or 9 Data Bits and 1 or 2 Stop Bits ? Odd or Even Parity Generation and Parity Check Supported by Hardware ? Data OverRun Detection ? Framing Error Detection ? Noise Filtering Includes False Start Bit Detection and Digital Low Pass Filter ? Three Separate Interrupts on TX Complete, TX Data Register Empty and RX Complete ? Multi-processor Communication Mode ? Double Speed Asynchronous Communica

### UDR1 - USART I/O Data Register

`sfrb UDR1 = $CE;`

##### UDR1-0 - USART I/O Data Register bit 0

`#define UDR1-0_BIT 0`

`#define UDR1-0_MASK 1`

##### UDR1-1 - USART I/O Data Register bit 1

`#define UDR1-1_BIT 1`

`#define UDR1-1_MASK 2`

##### UDR1-2 - USART I/O Data Register bit 2

`#define UDR1-2_BIT 2`

`#define UDR1-2_MASK 4`

##### UDR1-3 - USART I/O Data Register bit 3

`#define UDR1-3_BIT 3`

`#define UDR1-3_MASK 8`

##### UDR1-4 - USART I/O Data Register bit 4

`#define UDR1-4_BIT 4`

`#define UDR1-4_MASK 16`

##### UDR1-5 - USART I/O Data Register bit 5

`#define UDR1-5_BIT 5`

`#define UDR1-5_MASK 32`

##### UDR1-6 - USART I/O Data Register bit 6

`#define UDR1-6_BIT 6`

`#define UDR1-6_MASK 64`

##### UDR1-7 - USART I/O Data Register bit 7

`#define UDR1-7_BIT 7`

`#define UDR1-7_MASK 128`

### UCSR1A - USART Control and Status Register A

`sfrb UCSR1A = $C8;`

##### MPCM1 - Multi-processor Communication Mode

`#define MPCM1_BIT 0`

`#define MPCM1_MASK 1`

This bit enables the Multi-processor Communication Mode. When the MPCM bit is written to one, all the incoming frames received by the USART receiver that do not contain address information will be ignored. The transmitter is unaffected by the MPCM setting. For more detailed information see ?Multi-processor Communication Mode? on page 152.

##### U2X1 - Double the USART transmission speed

`#define U2X1_BIT 1`

`#define U2X1_MASK 2`

This bit only has effect for the asynchronous operation. Write this bit to zero when using synchronous operation. Writing this bit to one will reduce the divisor of the baud rate divider from 16 to 8 effectively doubling the transfer rate for asynchronous communication.

##### UPE1 - Parity Error

`#define UPE1_BIT 2`

`#define UPE1_MASK 4`

This bit is set if the next character in the receive buffer had a Parity Error when received and the parity checking was enabled at that point (UPM1 = 1). This bit is valid until the receive buffer (UDR0) is read. Always set this bit to zero when writing to UCSR0A.

##### DOR1 - Data overRun

`#define DOR1_BIT 3`

`#define DOR1_MASK 8`

This bit is set if an Overrun condition is detected, i.e. when a character already present in the UDRregister is not read before the next character has been shifted into the Receiver Shift register. The OR bit is buffered, which means that it will be set once the valid data still in UDR0E is read. The OR bit is cleared (zero) when data is received and transferred to UDR0.

##### FE1 - Framing Error

`#define FE1_BIT 4`

`#define FE1_MASK 16`

This bit is set if a Framing Error condition is detected, i.e. when the stop bit of an incoming character is zero. The FE bit is cleared when the stop bit of received data is one.

##### UDRE1 - USART Data Register Empty

`#define UDRE1_BIT 5`

`#define UDRE1_MASK 32`

This bit is set (one) when a character written to UDRis transferred to the Transmit shift register. Setting of this bit indicates that the transmitter is ready to receive a new character for transmission. When the UDR0IE bit in UCR is set, the USART Transmit Complete interrupt to be executed as long as UDR0E is set. UDR0E is cleared by writing UDR0. When interrupt-driven data transmittal is used, the USART Data Register Empty Interrupt routine must write UDRin order to clear UDR0E, otherwise a new interrupt will occur once the interrupt routine terminates. UDR0E is set (one) during reset to indicate that the transmitter is re

##### TXC1 - USART Transmitt Complete

`#define TXC1_BIT 6`

`#define TXC1_MASK 64`

This bit is set (one) when the entire character (including the stop bit) in the Transmit Shift register has been shifted out and no new data has been written to UDR0. This flag is especially useful in half-duplex communications interfaces, where a transmitting application must enter receive mode and free the communications bus immediately after completing the transmission. When the TXCIE bit in UCR is set, setting of TXC causes the USART Transmit Complete interrupt to be executed. TXC is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, the TXC bit is cleared (zero) by writing a logical one to the b

##### RXC1 - USART Receive Complete

`#define RXC1_BIT 7`

`#define RXC1_MASK 128`

This bit is set (one) when a received character is transferred from the Receiver Shift register to UDR0. The bit is set regard-less of any detected framing errors. When the RXCIE bit in UCR is set, the USART Receive Complete interrupt will be executed when RXC is set(one). RXC is cleared by reading UDR0. When interrupt-driven data reception is used, the USART Receive Complete Interrupt routine must read UDRin order to clear RXC, otherwise a new interrupt will occur once the interrupt routine terminates.

### UCSR1B - USART Control and Status Register B

`sfrb UCSR1B = $C9;`

##### TXB81 - Transmit Data Bit 8

`#define TXB81_BIT 0`

`#define TXB81_MASK 1`

TXB8 is the 9th data bit in the character to be transmitted when operating with serial frames with 9 data bits. Must be writ-ten before writing the low bits to UDR0.

##### RXB81 - Receive Data Bit 8

`#define RXB81_BIT 1`

`#define RXB81_MASK 2`

RXB8 is the 9th data bit of the received character when operating with serial frames with 9 data bits. Must be read before reading the low bits from UDR0.

##### UCSZ12 - Character Size

`#define UCSZ12_BIT 2`

`#define UCSZ12_MASK 4`

The UCSZ2 bits combined with the UCSZ1:0 bit in UCSR0C sets the number of data bits (character size) in a frame the receiver and transmitter use.

##### TXEN1 - Transmitter Enable

`#define TXEN1_BIT 3`

`#define TXEN1_MASK 8`

Writing this bit to one enables the USART transmitter. The transmitter will override normal port operation for the TxD pin when enabled. The disabling of the transmitter (writing TXEN to zero) will not become effective until ongoing and pending transmissions are completed, i.e. when the transmit shift register and transmit buffer register does not contain data to be transmitted. When disabled, the transmitter will no longer override the TxD port.

##### RXEN1 - Receiver Enable

`#define RXEN1_BIT 4`

`#define RXEN1_MASK 16`

Writing this bit to one enables the USART receiver. The receiver will override normal port operation for the RxD pin when enabled. Disabling the receiver will flush the receive buffer invalidating the FE, DOR and PE flags.

##### UDRIE1 - USART Data register Empty Interrupt Enable

`#define UDRIE1_BIT 5`

`#define UDRIE1_MASK 32`

Writing this bit to one enables interrupt on the UDR0E flag. A Data Register Empty interrupt will be generated only if the UDR0IE bit is written to one, the global interrupt flag in SREG is written to one and the UDR0E bit in UCSR0A is set.

##### TXCIE1 - TX Complete Interrupt Enable

`#define TXCIE1_BIT 6`

`#define TXCIE1_MASK 64`

Writing this bit to one enables interrupt on the TXC flag. A USART Transmit Complete interrupt will be generated only if the TXCIE bit is written to one, the global interrupt flag in SREG is written to one and the TXC bit in UCSR0A is set.

##### RXCIE1 - RX Complete Interrupt Enable

`#define RXCIE1_BIT 7`

`#define RXCIE1_MASK 128`

Writing this bit to one enables interrupt on the RXC flag. A USART Receive Complete interrupt will be generated only if the RXCIE bit is written to one, the global interrupt flag in SREG is written to one and the RXC bit in UCSR0A is set.

### UCSR1C - USART Control and Status Register C

`sfrb UCSR1C = $CA;`

##### UCPOL1 - Clock Polarity

`#define UCPOL1_BIT 0`

`#define UCPOL1_MASK 1`

This bit is used for synchronous mode only. Write this bit to zero when asynchronous mode is used. The UCPOL bit sets the relationship between data output change and data input sample, and the synchronous clock (XCK).

##### UCSZ10 - Character Size

`#define UCSZ10_BIT 1`

`#define UCSZ10_MASK 2`

Character Size: 0 0 0 = 5-bit. 0 0 1 = 6-bit. 0 1 0 = 7 bit. 0 1 1 = 8-bit. 1 1 1 = 9 bit.

##### UCSZ11 - Character Size

`#define UCSZ11_BIT 2`

`#define UCSZ11_MASK 4`

Character Size: 0 0 0 = 5-bit. 0 0 1 = 6-bit. 0 1 0 = 7 bit. 0 1 1 = 8-bit. 1 1 1 = 9 bit.

##### USBS1 - Stop Bit Select

`#define USBS1_BIT 3`

`#define USBS1_MASK 8`

0: 1-bit. 1: 2-bit.

##### UPM10 - Parity Mode Bit 0

`#define UPM10_BIT 4`

`#define UPM10_MASK 16`

This bit enable and set type of parity generation and check. If enabled, the transmitter will automatically generate and send the parity of the transmitted data bits within each frame. The receiver will generate a parity value for the incoming data and compare it to the UPM0 setting. If a mismatch is detected, the PE flag in UCSR0A will be set.

##### UPM11 - Parity Mode Bit 1

`#define UPM11_BIT 5`

`#define UPM11_MASK 32`

This bit enable and set type of parity generation and check. If enabled, the transmitter will automatically generate and send the parity of the transmitted data bits within each frame. The receiver will generate a parity value for the incoming data and compare it to the UPM0 setting. If a mismatch is detected, the PE flag in UCSR0A will be set.

##### UMSEL10 - USART Mode Select

`#define UMSEL10_BIT 6`

`#define UMSEL10_MASK 64`

##### UMSEL11 - USART Mode Select

`#define UMSEL11_BIT 7`

`#define UMSEL11_MASK 128`

### UBRR1H - USART Baud Rate Register High Byte

`sfrb UBRR1H = $CD;`

##### UBRR8 - USART Baud Rate Register bit 8

`#define UBRR8_BIT 0`

`#define UBRR8_MASK 1`

##### UBRR9 - USART Baud Rate Register bit 9

`#define UBRR9_BIT 1`

`#define UBRR9_MASK 2`

##### UBRR10 - USART Baud Rate Register bit 10

`#define UBRR10_BIT 2`

`#define UBRR10_MASK 4`

##### UBRR11 - USART Baud Rate Register bit 11

`#define UBRR11_BIT 3`

`#define UBRR11_MASK 8`

### UBRR1L - USART Baud Rate Register Low Byte

`sfrb UBRR1L = $CC;`

##### UBRR0 - USART Baud Rate Register bit 0

`#define UBRR0_BIT 0`

`#define UBRR0_MASK 1`

##### UBRR1 - USART Baud Rate Register bit 1

`#define UBRR1_BIT 1`

`#define UBRR1_MASK 2`

##### UBRR2 - USART Baud Rate Register bit 2

`#define UBRR2_BIT 2`

`#define UBRR2_MASK 4`

##### UBRR3 - USART Baud Rate Register bit 3

`#define UBRR3_BIT 3`

`#define UBRR3_MASK 8`

##### UBRR4 - USART Baud Rate Register bit 4

`#define UBRR4_BIT 4`

`#define UBRR4_MASK 16`

##### UBRR5 - USART Baud Rate Register bit 5

`#define UBRR5_BIT 5`

`#define UBRR5_MASK 32`

##### UBRR6 - USART Baud Rate Register bit 6

`#define UBRR6_BIT 6`

`#define UBRR6_MASK 64`

##### UBRR7 - USART Baud Rate Register bit 7

`#define UBRR7_BIT 7`

`#define UBRR7_MASK 128`

## EEPROM

EEPROM Read/Write Access. The EEPROM access registers are accessible in the I/O space. The write access time for the EEPROM is given in Table 1. A self-timing function, however, lets the user software detect when the next byte can be written. If the user code contains instructions that write the EEPROM, some precautions must be taken. In heavily filtered power supplies, V CC is likely to rise or fall slowly on power-up/down. This causes the device for some period of time to run at a voltage lower than specified as minimum for the clock frequency used. See ?Preventing EEPROM Corruption? on page 19. for details on how to avoid problems in these situations.In order to prevent unintentional EEPROM writes, a specific write procedure must be followed. Refer to the description of the EEPROM Control Register for details on this. When the EEPROM is read, the CPU is halted for four clock cycles before the next instruction is executed. When theEEPROM is written, the CPU is halted for two clock cycles before the next instruction is execute

### EEARH - EEPROM Address Register Low Byte

`sfrb EEARH = $22;`

##### EEAR8 - EEPROM Read/Write Access Bit 8

`#define EEAR8_BIT 0`

`#define EEAR8_MASK 1`

##### EEAR9 - EEPROM Read/Write Access Bit 9

`#define EEAR9_BIT 1`

`#define EEAR9_MASK 2`

##### EEAR10 - EEPROM Read/Write Access Bit 10

`#define EEAR10_BIT 2`

`#define EEAR10_MASK 4`

##### EEAR11 - EEPROM Read/Write Access Bit 11

`#define EEAR11_BIT 3`

`#define EEAR11_MASK 8`

### EEARL - EEPROM Address Register Low Byte

`sfrb EEARL = $21;`

##### EEAR0 - EEPROM Read/Write Access Bit 0

`#define EEAR0_BIT 0`

`#define EEAR0_MASK 1`

##### EEAR1 - EEPROM Read/Write Access Bit 1

`#define EEAR1_BIT 1`

`#define EEAR1_MASK 2`

##### EEAR2 - EEPROM Read/Write Access Bit 2

`#define EEAR2_BIT 2`

`#define EEAR2_MASK 4`

##### EEAR3 - EEPROM Read/Write Access Bit 3

`#define EEAR3_BIT 3`

`#define EEAR3_MASK 8`

##### EEAR4 - EEPROM Read/Write Access Bit 4

`#define EEAR4_BIT 4`

`#define EEAR4_MASK 16`

##### EEAR5 - EEPROM Read/Write Access Bit 5

`#define EEAR5_BIT 5`

`#define EEAR5_MASK 32`

##### EEAR6 - EEPROM Read/Write Access Bit 6

`#define EEAR6_BIT 6`

`#define EEAR6_MASK 64`

##### EEAR7 - EEPROM Read/Write Access Bit 7

`#define EEAR7_BIT 7`

`#define EEAR7_MASK 128`

### EEDR - EEPROM Data Register

`sfrb EEDR = $20;`

##### EEDR0 - EEPROM Data Register bit 0

`#define EEDR0_BIT 0`

`#define EEDR0_MASK 1`

##### EEDR1 - EEPROM Data Register bit 1

`#define EEDR1_BIT 1`

`#define EEDR1_MASK 2`

##### EEDR2 - EEPROM Data Register bit 2

`#define EEDR2_BIT 2`

`#define EEDR2_MASK 4`

##### EEDR3 - EEPROM Data Register bit 3

`#define EEDR3_BIT 3`

`#define EEDR3_MASK 8`

##### EEDR4 - EEPROM Data Register bit 4

`#define EEDR4_BIT 4`

`#define EEDR4_MASK 16`

##### EEDR5 - EEPROM Data Register bit 5

`#define EEDR5_BIT 5`

`#define EEDR5_MASK 32`

##### EEDR6 - EEPROM Data Register bit 6

`#define EEDR6_BIT 6`

`#define EEDR6_MASK 64`

##### EEDR7 - EEPROM Data Register bit 7

`#define EEDR7_BIT 7`

`#define EEDR7_MASK 128`

### EECR - EEPROM Control Register

`sfrb EECR = $1F;`

##### EERE - EEPROM Read Enable

`#define EERE_BIT 0`

`#define EERE_MASK 1`

The EEPROM Read Enable Signal EERE is the read strobe to the EEPROM. When the correct address is set up in the EEAR register, the EERE bit must be written to a logic one to trigger the EEPROM read. The EEPROM read access takes one instruction, and the requested data is available immediately. When the EEPROM is read, the CPU is halted for four cycles before the next instruction is executed. The user should poll the EEWE bit before starting the read operation. If a write operation is in progress, it is neither possible to read the EEPROM, nor to change the EEAR register. The calibrated oscillator is used to time the EEPROM accesses. Table 1 lists the typical programming time for EEPROM access from the CPU

##### EEPE - EEPROM Write Enable

`#define EEPE_BIT 1`

`#define EEPE_MASK 2`

The EEPROM Write Enable Signal EEWE is the write strobe to the EEPROM. When address and data are correctly set up, the EEWE bit must be set to write the value into the EEPROM. The EEMWE bit must be set when the logical one is written to EEWE, otherwise no EEPROM write takes place. The following procedure should be followed when writing the EEPROM (the order of steps 3 and 4 is not essential): 1. Wait until EEWE becomes zero. 2. Wait until SPMEN in SPMCR becomes zero. 3. Write new EEPROM address to EEAR (optional). 4. Write new EEPROM data to EEDR (optional). 5. Write a logical one to the EEMWE bit while writing a zero to EEWE in EECR. 6. Within four clock cycles after setting EEMWE, write a logical one to EEWE. The EEPROM can not be programmed during a CPU write to the Flash memory. The software must check that the Flash programming is completed before initiating a new EEPROM write. Step 2 is only relevant if the software contains a boot loader allowing the CPU to program the Flash. If the Flash is never being updated by the CPU, step 2 can be omitted. See ?Boot Loader Support - Read While Write self-programming? on page 228 for details about boot programming. Caution: An interrupt between step 5 and step 6 will make the write cycle fail, since the EEPROM Master Write Enable will time-out. If an interrupt routine accessing the EEPROM is interrupting another EEPROM access, the EEAR or EEDR regis-ter will be modified, causing the interrupted EEPROM access to fail. It is recommended to have the global interrupt flag cleared during the 4 last steps to avoid these problems. When the write access time has elapsed, the EEWE bit is cleared by hardware. The user software can poll this bit and wait for a zero before writing the next byte. When EEWE has been set, the CPU is halted for two cycles before the next instruc-tion is executed

##### EEMPE - EEPROM Master Write Enable

`#define EEMPE_BIT 2`

`#define EEMPE_MASK 4`

The EEMWE bit determines whether setting EEWE to one causes the EEPROM to be written. When EEMWE is written to one, writing EEWE to one within 4 clock cycles will write data to the EEPROM at the selected address. If EEMWE is zero, writing EEWE to one will have no effect. When EEMWE has been written to one by software, hardware clears the bit to zero after four clock cycles. See the description of the EEWE bit for an EEPROM write procedure.

##### EERIE - EEPROM Ready Interrupt Enable

`#define EERIE_BIT 3`

`#define EERIE_MASK 8`

EEPROM Ready Interrupt Enable Writing EERIE to one enables the EEPROM Ready Interrupt if the I bit in SREG is set. Writing EERIE to zero disables the interrupt. The EEPROM Ready interrupt generates a constant interrupt when EEWE is cleared.

##### EEPM0 - EEPROM Programming Mode Bit 0

`#define EEPM0_BIT 4`

`#define EEPM0_MASK 16`

The EEPROM Programming mode bit setting defines which programming action that will be triggered when writing EEPE. It is possible to program data in one atomic operation (erase the old value and program the new value) or to split the Erase and Write operations in two different operations. The Programming times for the different modes are shown in Table 2. While EEPE is set, any write to EEPMn will be ignored. During reset, the EEPMn bits will be reset to 0b00 unless the EEPROM is busy programming.

##### EEPM1 - EEPROM Programming Mode Bit 1

`#define EEPM1_BIT 5`

`#define EEPM1_MASK 32`

The EEPROM Programming mode bit setting defines which programming action that will be triggered when writing EEPE. It is possible to program data in one atomic operation (erase the old value and program the new value) or to split the Erase and Write operations in two different operations. The Programming times for the different modes are shown in Table 2. While EEPE is set, any write to EEPMn will be ignored. During reset, the EEPMn bits will be reset to 0b00 unless the EEPROM is busy programming.

## TIMER COUNTER 5

### TCCR5A - Timer/Counter5 Control Register A

`sfrb TCCR5A = $120;`

##### WGM50 - Waveform Generation Mode

`#define WGM50_BIT 0`

`#define WGM50_MASK 1`

Combined with the WGM53:2 bits found in the TCCR5B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### WGM51 - Waveform Generation Mode

`#define WGM51_BIT 1`

`#define WGM51_MASK 2`

Combined with the WGM53:2 bits found in the TCCR5B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### COM5C0 - Compare Output Mode 5C, bit 0

`#define COM5C0_BIT 2`

`#define COM5C0_MASK 4`

The COM5C1 and COM5C0 control bits determine any output pin action following a compare match in Timer/Counter5. Any output pin actions affect pin OC5B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM5C1 - Compare Output Mode 5C, bit 1

`#define COM5C1_BIT 3`

`#define COM5C1_MASK 8`

The COM5C1 and COM5C0 control bits determine any output pin action following a compare match in Timer/Counter5. Any output pin actions affect pin OC5B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM5B0 - Compare Output Mode 5B, bit 0

`#define COM5B0_BIT 4`

`#define COM5B0_MASK 16`

The COM5B1 and COM5B0 control bits determine any output pin action following a compare match in Timer/Counter5. Any output pin actions affect pin OC5B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM5B1 - Compare Output Mode 5B, bit 1

`#define COM5B1_BIT 5`

`#define COM5B1_MASK 32`

The COM5B1 and COM5B0 control bits determine any output pin action following a compare match in Timer/Counter5. Any output pin actions affect pin OC5B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM5A0 - Compare Output Mode 5A, bit 0

`#define COM5A0_BIT 6`

`#define COM5A0_MASK 64`

The COM5A1 and COM5A0 control bits determine any output pin action following a compare match in Timer/Counter5. Any output pin actions affect pin OC5A - Output CompareA. This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. The control configuration is shown in Table 10.

##### COM5A1 - Compare Output Mode 1A, bit 1

`#define COM5A1_BIT 7`

`#define COM5A1_MASK 128`

The COM5A1 and COM5A0 control bits determine any output pin action following a compare match in Timer/Counter5. Any output pin actions affect pin OC5A - Output CompareA. This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. The control configuration is shown in Table 10.

### TCCR5B - Timer/Counter5 Control Register B

`sfrb TCCR5B = $121;`

##### CS50 - Prescaler source of Timer/Counter 5

`#define CS50_BIT 0`

`#define CS50_MASK 1`

Select Prescaling Clock Source of Timer/Counter5. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T1, falling edge. (1:1:1) = External Pin 1, rising edge.

##### CS51 - Prescaler source of Timer/Counter 5

`#define CS51_BIT 1`

`#define CS51_MASK 2`

Select Prescaling Clock Source of Timer/Counter5. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T5, falling edge. (1:1:1) = External Pin 1, rising edge.

##### CS52 - Prescaler source of Timer/Counter 5

`#define CS52_BIT 2`

`#define CS52_MASK 4`

Select Prescaling Clock Source of Timer/Counter5. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T5, falling edge. (1:1:1) = External Pin 1, rising edge.

##### WGM52 - Waveform Generation Mode

`#define WGM52_BIT 3`

`#define WGM52_MASK 8`

Combined with the WGM53:2 bits found in the TCCR5B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### WGM53 - Waveform Generation Mode

`#define WGM53_BIT 4`

`#define WGM53_MASK 16`

Combined with the WGM53:2 bits found in the TCCR5B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### ICES5 - Input Capture 5 Edge Select

`#define ICES5_BIT 6`

`#define ICES5_MASK 64`

While the ICES5 bit is cleared (zero), the Timer/Counter5 contents are transferred to the Input Capture Register - ICR5 - on the falling edge of the input capture pin - ICP. While the ICES5 bit is set (one), the Timer/Counter5 contents are transferred to the Input Capture Register - ICR5 - on the rising edge of the input capture pin - ICP.

##### ICNC5 - Input Capture 5 Noise Canceler

`#define ICNC5_BIT 7`

`#define ICNC5_MASK 128`

When the ICNC5 bit is cleared (zero), the input capture trigger noise canceler function is disabled. The input capture is triggered at the first rising/falling edge sampled on the ICP - input capture pin - as specified. When the ICNC5 bit is set (one), four successive samples are measures on the ICP - input capture pin, and all samples must be high/low according to the input capture trigger specification in the ICES5 bit. The actual sampling frequency is XTAL clock frequency.

### TCCR5C - Timer/Counter 5 Control Register C

`sfrb TCCR5C = $122;`

##### FOC5C - Force Output Compare 5C

`#define FOC5C_BIT 5`

`#define FOC5C_MASK 32`

Writing a logical one to this bit, forces a change in the compare match output pin PD4 according to the values already set in COM5B1 and COM5B0.If the COM5B1 and COM5B0 bits are written in the same cycle as FOC5B,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM5B1 and COM5B0 happens as if a Compare Match had occurred, but no interrupt is generated. The corresponding I/O pin must be set as an output pin for the FOC5B bit to have effect on the pin. The FOC5B bit will always be read as zero. The setting of the FOC5B bit has no effect in PWM mo

##### FOC5B - Force Output Compare 5B

`#define FOC5B_BIT 6`

`#define FOC5B_MASK 64`

Writing a logical one to this bit, forces a change in the compare match output pin PD4 according to the values already set in COM5B1 and COM5B0.If the COM5B1 and COM5B0 bits are written in the same cycle as FOC5B,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM5B1 and COM5B0 happens as if a Compare Match had occurred, but no interrupt is generated. The corresponding I/O pin must be set as an output pin for the FOC5B bit to have effect on the pin. The FOC5B bit will always be read as zero. The setting of the FOC5B bit has no effect in PWM mo

##### FOC5A - Force Output Compare 5A

`#define FOC5A_BIT 7`

`#define FOC5A_MASK 128`

Writing a logical one to this bit, forces a change in the compare match output pin PD5 according to the values already set in COM5A1 and COM5A0.If the COM5A1 and COM5A0 bits are written in the same cycle as FOC5A,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM5A1 and COM5A0 happens as if a Compare Match had occurred, but no interrupt is generated and it will not clear the timer even if CTC5 in TCCR5B is set. The corresponding I/O pin must be set as an output pin for the FOC5A bit to have effect on the pin. The FOC5A bit will always be read as zero. The setting of the FOC5A bit has no effect in PWM m

### TCNT5H - Timer/Counter5 High Byte

`sfrb TCNT5H = $125;`

##### TCNT5H0 - Timer/Counter5 High Byte bit 0

`#define TCNT5H0_BIT 0`

`#define TCNT5H0_MASK 1`

##### TCNT5H1 - Timer/Counter5 High Byte bit 1

`#define TCNT5H1_BIT 1`

`#define TCNT5H1_MASK 2`

##### TCNT5H2 - Timer/Counter5 High Byte bit 2

`#define TCNT5H2_BIT 2`

`#define TCNT5H2_MASK 4`

##### TCNT5H3 - Timer/Counter5 High Byte bit 3

`#define TCNT5H3_BIT 3`

`#define TCNT5H3_MASK 8`

##### TCNT5H4 - Timer/Counter5 High Byte bit 4

`#define TCNT5H4_BIT 4`

`#define TCNT5H4_MASK 16`

##### TCNT5H5 - Timer/Counter5 High Byte bit 5

`#define TCNT5H5_BIT 5`

`#define TCNT5H5_MASK 32`

##### TCNT5H6 - Timer/Counter5 High Byte bit 6

`#define TCNT5H6_BIT 6`

`#define TCNT5H6_MASK 64`

##### TCNT5H7 - Timer/Counter5 High Byte bit 7

`#define TCNT5H7_BIT 7`

`#define TCNT5H7_MASK 128`

### TCNT5L - Timer/Counter5 Low Byte

`sfrb TCNT5L = $124;`

##### TCNT5L0 - Timer/Counter5 Low Byte bit 0

`#define TCNT5L0_BIT 0`

`#define TCNT5L0_MASK 1`

##### TCNT5L1 - Timer/Counter5 Low Byte bit 1

`#define TCNT5L1_BIT 1`

`#define TCNT5L1_MASK 2`

##### TCNT5L2 - Timer/Counter5 Low Byte bit 2

`#define TCNT5L2_BIT 2`

`#define TCNT5L2_MASK 4`

##### TCNT5L3 - Timer/Counter5 Low Byte bit 3

`#define TCNT5L3_BIT 3`

`#define TCNT5L3_MASK 8`

##### TCNT5L4 - Timer/Counter5 Low Byte bit 4

`#define TCNT5L4_BIT 4`

`#define TCNT5L4_MASK 16`

##### TCNT5L5 - Timer/Counter5 Low Byte bit 5

`#define TCNT5L5_BIT 5`

`#define TCNT5L5_MASK 32`

##### TCNT5L6 - Timer/Counter5 Low Byte bit 6

`#define TCNT5L6_BIT 6`

`#define TCNT5L6_MASK 64`

##### TCNT5L7 - Timer/Counter5 Low Byte bit 7

`#define TCNT5L7_BIT 7`

`#define TCNT5L7_MASK 128`

### OCR5AH - Timer/Counter5 Outbut Compare Register A High Byte

`sfrb OCR5AH = $129;`

##### OCR5AH0 - Timer/Counter5 Outbut Compare Register High Byte bit 0

`#define OCR5AH0_BIT 0`

`#define OCR5AH0_MASK 1`

##### OCR5AH1 - Timer/Counter5 Outbut Compare Register High Byte bit 1

`#define OCR5AH1_BIT 1`

`#define OCR5AH1_MASK 2`

##### OCR5AH2 - Timer/Counter5 Outbut Compare Register High Byte bit 2

`#define OCR5AH2_BIT 2`

`#define OCR5AH2_MASK 4`

##### OCR5AH3 - Timer/Counter5 Outbut Compare Register High Byte bit 3

`#define OCR5AH3_BIT 3`

`#define OCR5AH3_MASK 8`

##### OCR5AH4 - Timer/Counter5 Outbut Compare Register High Byte bit 4

`#define OCR5AH4_BIT 4`

`#define OCR5AH4_MASK 16`

##### OCR5AH5 - Timer/Counter5 Outbut Compare Register High Byte bit 5

`#define OCR5AH5_BIT 5`

`#define OCR5AH5_MASK 32`

##### OCR5AH6 - Timer/Counter5 Outbut Compare Register High Byte bit 6

`#define OCR5AH6_BIT 6`

`#define OCR5AH6_MASK 64`

##### OCR5AH7 - Timer/Counter5 Outbut Compare Register High Byte bit 7

`#define OCR5AH7_BIT 7`

`#define OCR5AH7_MASK 128`

### OCR5AL - Timer/Counter5 Outbut Compare Register A Low Byte

`sfrb OCR5AL = $128;`

##### OCR5AL0 - Timer/Counter5 Outbut Compare Register Low Byte Bit 0

`#define OCR5AL0_BIT 0`

`#define OCR5AL0_MASK 1`

##### OCR5AL1 - Timer/Counter5 Outbut Compare Register Low Byte Bit 1

`#define OCR5AL1_BIT 1`

`#define OCR5AL1_MASK 2`

##### OCR5AL2 - Timer/Counter5 Outbut Compare Register Low Byte Bit 2

`#define OCR5AL2_BIT 2`

`#define OCR5AL2_MASK 4`

##### OCR5AL3 - Timer/Counter5 Outbut Compare Register Low Byte Bit 3

`#define OCR5AL3_BIT 3`

`#define OCR5AL3_MASK 8`

##### OCR5AL4 - Timer/Counter5 Outbut Compare Register Low Byte Bit 4

`#define OCR5AL4_BIT 4`

`#define OCR5AL4_MASK 16`

##### OCR5AL5 - Timer/Counter5 Outbut Compare Register Low Byte Bit 5

`#define OCR5AL5_BIT 5`

`#define OCR5AL5_MASK 32`

##### OCR5AL6 - Timer/Counter5 Outbut Compare Register Low Byte Bit 6

`#define OCR5AL6_BIT 6`

`#define OCR5AL6_MASK 64`

##### OCR5AL7 - Timer/Counter5 Outbut Compare Register Low Byte Bit 7

`#define OCR5AL7_BIT 7`

`#define OCR5AL7_MASK 128`

### OCR5BH - Timer/Counter5 Output Compare Register B High Byte

`sfrb OCR5BH = $12B;`

##### OCR5BH0 - Timer/Counter5 Output Compare Register High Byte bit 0

`#define OCR5BH0_BIT 0`

`#define OCR5BH0_MASK 1`

##### OCR5BH1 - Timer/Counter5 Output Compare Register High Byte bit 1

`#define OCR5BH1_BIT 1`

`#define OCR5BH1_MASK 2`

##### OCR5BH2 - Timer/Counter5 Output Compare Register High Byte bit 2

`#define OCR5BH2_BIT 2`

`#define OCR5BH2_MASK 4`

##### OCR5BH3 - Timer/Counter5 Output Compare Register High Byte bit 3

`#define OCR5BH3_BIT 3`

`#define OCR5BH3_MASK 8`

##### OCR5BH4 - Timer/Counter5 Output Compare Register High Byte bit 4

`#define OCR5BH4_BIT 4`

`#define OCR5BH4_MASK 16`

##### OCR5BH5 - Timer/Counter5 Output Compare Register High Byte bit 5

`#define OCR5BH5_BIT 5`

`#define OCR5BH5_MASK 32`

##### OCR5BH6 - Timer/Counter5 Output Compare Register High Byte bit 6

`#define OCR5BH6_BIT 6`

`#define OCR5BH6_MASK 64`

##### OCR5BH7 - Timer/Counter5 Output Compare Register High Byte bit 7

`#define OCR5BH7_BIT 7`

`#define OCR5BH7_MASK 128`

### OCR5BL - Timer/Counter5 Output Compare Register B Low Byte

`sfrb OCR5BL = $12A;`

##### OCR5BL0 - Timer/Counter5 Output Compare Register Low Byte bit 0

`#define OCR5BL0_BIT 0`

`#define OCR5BL0_MASK 1`

##### OCR5BL1 - Timer/Counter5 Output Compare Register Low Byte bit 1

`#define OCR5BL1_BIT 1`

`#define OCR5BL1_MASK 2`

##### OCR5BL2 - Timer/Counter5 Output Compare Register Low Byte bit 2

`#define OCR5BL2_BIT 2`

`#define OCR5BL2_MASK 4`

##### OCR5BL3 - Timer/Counter5 Output Compare Register Low Byte bit 3

`#define OCR5BL3_BIT 3`

`#define OCR5BL3_MASK 8`

##### OCR5BL4 - Timer/Counter5 Output Compare Register Low Byte bit 4

`#define OCR5BL4_BIT 4`

`#define OCR5BL4_MASK 16`

##### OCR5BL5 - Timer/Counter5 Output Compare Register Low Byte bit 5

`#define OCR5BL5_BIT 5`

`#define OCR5BL5_MASK 32`

##### OCR5BL6 - Timer/Counter5 Output Compare Register Low Byte bit 6

`#define OCR5BL6_BIT 6`

`#define OCR5BL6_MASK 64`

##### OCR5BL7 - Timer/Counter5 Output Compare Register Low Byte bit 7

`#define OCR5BL7_BIT 7`

`#define OCR5BL7_MASK 128`

### OCR5CH - Timer/Counter5 Output Compare Register B High Byte

`sfrb OCR5CH = $12D;`

##### OCR5CH0 - Timer/Counter5 Output Compare Register High Byte bit 0

`#define OCR5CH0_BIT 0`

`#define OCR5CH0_MASK 1`

##### OCR5CH1 - Timer/Counter5 Output Compare Register High Byte bit 1

`#define OCR5CH1_BIT 1`

`#define OCR5CH1_MASK 2`

##### OCR5CH2 - Timer/Counter5 Output Compare Register High Byte bit 2

`#define OCR5CH2_BIT 2`

`#define OCR5CH2_MASK 4`

##### OCR5CH3 - Timer/Counter5 Output Compare Register High Byte bit 3

`#define OCR5CH3_BIT 3`

`#define OCR5CH3_MASK 8`

##### OCR5CH4 - Timer/Counter5 Output Compare Register High Byte bit 4

`#define OCR5CH4_BIT 4`

`#define OCR5CH4_MASK 16`

##### OCR5CH5 - Timer/Counter5 Output Compare Register High Byte bit 5

`#define OCR5CH5_BIT 5`

`#define OCR5CH5_MASK 32`

##### OCR5CH6 - Timer/Counter5 Output Compare Register High Byte bit 6

`#define OCR5CH6_BIT 6`

`#define OCR5CH6_MASK 64`

##### OCR5CH7 - Timer/Counter5 Output Compare Register High Byte bit 7

`#define OCR5CH7_BIT 7`

`#define OCR5CH7_MASK 128`

### OCR5CL - Timer/Counter5 Output Compare Register B Low Byte

`sfrb OCR5CL = $12C;`

##### OCR5CL0 - Timer/Counter5 Output Compare Register Low Byte bit 0

`#define OCR5CL0_BIT 0`

`#define OCR5CL0_MASK 1`

##### OCR5CL1 - Timer/Counter5 Output Compare Register Low Byte bit 1

`#define OCR5CL1_BIT 1`

`#define OCR5CL1_MASK 2`

##### OCR5CL2 - Timer/Counter5 Output Compare Register Low Byte bit 2

`#define OCR5CL2_BIT 2`

`#define OCR5CL2_MASK 4`

##### OCR5CL3 - Timer/Counter5 Output Compare Register Low Byte bit 3

`#define OCR5CL3_BIT 3`

`#define OCR5CL3_MASK 8`

##### OCR5CL4 - Timer/Counter5 Output Compare Register Low Byte bit 4

`#define OCR5CL4_BIT 4`

`#define OCR5CL4_MASK 16`

##### OCR5CL5 - Timer/Counter5 Output Compare Register Low Byte bit 5

`#define OCR5CL5_BIT 5`

`#define OCR5CL5_MASK 32`

##### OCR5CL6 - Timer/Counter5 Output Compare Register Low Byte bit 6

`#define OCR5CL6_BIT 6`

`#define OCR5CL6_MASK 64`

##### OCR5CL7 - Timer/Counter5 Output Compare Register Low Byte bit 7

`#define OCR5CL7_BIT 7`

`#define OCR5CL7_MASK 128`

### ICR5H - Timer/Counter5 Input Capture Register High Byte

`sfrb ICR5H = $127;`

##### ICR5H0 - Timer/Counter5 Input Capture Register High Byte bit 0

`#define ICR5H0_BIT 0`

`#define ICR5H0_MASK 1`

##### ICR5H1 - Timer/Counter5 Input Capture Register High Byte bit 1

`#define ICR5H1_BIT 1`

`#define ICR5H1_MASK 2`

##### ICR5H2 - Timer/Counter5 Input Capture Register High Byte bit 2

`#define ICR5H2_BIT 2`

`#define ICR5H2_MASK 4`

##### ICR5H3 - Timer/Counter5 Input Capture Register High Byte bit 3

`#define ICR5H3_BIT 3`

`#define ICR5H3_MASK 8`

##### ICR5H4 - Timer/Counter5 Input Capture Register High Byte bit 4

`#define ICR5H4_BIT 4`

`#define ICR5H4_MASK 16`

##### ICR5H5 - Timer/Counter5 Input Capture Register High Byte bit 5

`#define ICR5H5_BIT 5`

`#define ICR5H5_MASK 32`

##### ICR5H6 - Timer/Counter5 Input Capture Register High Byte bit 6

`#define ICR5H6_BIT 6`

`#define ICR5H6_MASK 64`

##### ICR5H7 - Timer/Counter5 Input Capture Register High Byte bit 7

`#define ICR5H7_BIT 7`

`#define ICR5H7_MASK 128`

### ICR5L - Timer/Counter5 Input Capture Register Low Byte

`sfrb ICR5L = $126;`

##### ICR5L0 - Timer/Counter5 Input Capture Register Low Byte bit 0

`#define ICR5L0_BIT 0`

`#define ICR5L0_MASK 1`

##### ICR5L1 - Timer/Counter5 Input Capture Register Low Byte bit 1

`#define ICR5L1_BIT 1`

`#define ICR5L1_MASK 2`

##### ICR5L2 - Timer/Counter5 Input Capture Register Low Byte bit 2

`#define ICR5L2_BIT 2`

`#define ICR5L2_MASK 4`

##### ICR5L3 - Timer/Counter5 Input Capture Register Low Byte bit 3

`#define ICR5L3_BIT 3`

`#define ICR5L3_MASK 8`

##### ICR5L4 - Timer/Counter5 Input Capture Register Low Byte bit 4

`#define ICR5L4_BIT 4`

`#define ICR5L4_MASK 16`

##### ICR5L5 - Timer/Counter5 Input Capture Register Low Byte bit 5

`#define ICR5L5_BIT 5`

`#define ICR5L5_MASK 32`

##### ICR5L6 - Timer/Counter5 Input Capture Register Low Byte bit 6

`#define ICR5L6_BIT 6`

`#define ICR5L6_MASK 64`

##### ICR5L7 - Timer/Counter5 Input Capture Register Low Byte bit 7

`#define ICR5L7_BIT 7`

`#define ICR5L7_MASK 128`

### TIMSK5 - Timer/Counter5 Interrupt Mask Register

`sfrb TIMSK5 = $73;`

##### TOIE5 - Timer/Counter5 Overflow Interrupt Enable

`#define TOIE5_BIT 0`

`#define TOIE5_MASK 1`

When the TOIE5 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter5 Overflow interrupt is enabled. The corresponding interrupt (at vector $006) is executed if an overflow in Timer/Counter5 occurs, i.e., when the TOV5 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE5A - Timer/Counter5 Output Compare A Match Interrupt Enable

`#define OCIE5A_BIT 1`

`#define OCIE5A_MASK 2`

When the OCIE5A bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter5 CompareA Match interrupt is enabled. The corresponding interrupt (at vector $004) is executed if a CompareA match in Timer/Counter5 occurs, i.e., when the OCF5A bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE5B - Timer/Counter5 Output Compare B Match Interrupt Enable

`#define OCIE5B_BIT 2`

`#define OCIE5B_MASK 4`

When the OCIE5B bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter5 CompareB Match interrupt is enabled. The corresponding interrupt (at vector $005) is executed if a CompareB match in Timer/Counter5 occurs, i.e., when the OCF5B bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE5C - Timer/Counter5 Output Compare C Match Interrupt Enable

`#define OCIE5C_BIT 3`

`#define OCIE5C_MASK 8`

When the OCIE5C bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter5 CompareB Match interrupt is enabled. The corresponding interrupt (at vector $005) is executed if a CompareB match in Timer/Counter5 occurs, i.e., when the OCF5B bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### ICIE5 - Timer/Counter5 Input Capture Interrupt Enable

`#define ICIE5_BIT 5`

`#define ICIE5_MASK 32`

When the TICIE5 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter5 Input Capture Event Interrupt is enabled. The corresponding interrupt (at vector $003) is executed if a capture-triggering event occurs on pin 31, ICP, i.e., when the ICF5 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

### TIFR5 - Timer/Counter5 Interrupt Flag register

`sfrb TIFR5 = $1A;`

##### TOV5 - Timer/Counter5 Overflow Flag

`#define TOV5_BIT 0`

`#define TOV5_MASK 1`

The TOV5 is set (one) when an overflow occurs in Timer/Counter5. TOV5 is cleared by hardware when executing the cor-responding interrupt handling vector. Alternatively, TOV5 is cleared by writing a logic one to the flag. When the I-bit in SREG, and TOIE5 (Timer/Counter5 Overflow Interrupt Enable), and TOV5 are set (one), the Timer/Counter5 Overflow Interrupt is executed. In PWM mode, this bit is set when Timer/Counter5 changes counting direction at $0000.

##### OCF5A - Output Compare Flag 5A

`#define OCF5A_BIT 1`

`#define OCF5A_MASK 2`

The OCF5A bit is set (one) when compare match occurs between the Timer/Counter5 and the data in OCR5A - Output Compare Register 5A. OCF5A is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF5A is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE5A (Timer/Counter5 Compare match InterruptA Enable), and the OCF5A are set (one), the Timer/Counter5 Compare A match Interrupt is executed.

##### OCF5B - Output Compare Flag 5B

`#define OCF5B_BIT 2`

`#define OCF5B_MASK 4`

The OCF5B bit is set (one) when compare match occurs between the Timer/Counter5 and the data in OCR5B - Output Compare Register 5B. OCF5B is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF5B is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE5B (Timer/Counter5 Compare match InterruptB Enable), and the OCF5B are set (one), the Timer/Counter5 Compare B match Interrupt is executed.

##### OCF5C - Output Compare Flag 5C

`#define OCF5C_BIT 3`

`#define OCF5C_MASK 8`

The OCF5C bit is set (one) when compare match occurs between the Timer/Counter5 and the data in OCR5B - Output Compare Register 5B. OCF5B is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF5B is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE5B (Timer/Counter5 Compare match InterruptB Enable), and the OCF5B are set (one), the Timer/Counter5 Compare B match Interrupt is executed.

##### ICF5 - Input Capture Flag 5

`#define ICF5_BIT 5`

`#define ICF5_MASK 32`

The ICF5 bit is set (one) to flag an input capture event, indicating that the Timer/Counter5 value has been transferred to the input capture register - ICR5. ICF5 is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, ICF5 is cleared by writing a logic one to the flag. When the SREG I-bit, and TICIE5 (Timer/Counter5 Input Capture Interrupt Enable), and ICF5 are set (one), the Timer/Counter5 Capture Interrupt is executed.

## TIMER COUNTER 4

### TCCR4A - Timer/Counter4 Control Register A

`sfrb TCCR4A = $A0;`

##### WGM40 - Waveform Generation Mode

`#define WGM40_BIT 0`

`#define WGM40_MASK 1`

Combined with the WGM43:2 bits found in the TCCR4B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### WGM41 - Waveform Generation Mode

`#define WGM41_BIT 1`

`#define WGM41_MASK 2`

Combined with the WGM43:2 bits found in the TCCR4B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### COM4C0 - Compare Output Mode 4C, bit 0

`#define COM4C0_BIT 2`

`#define COM4C0_MASK 4`

The COM4C1 and COM4C0 control bits determine any output pin action following a compare match in Timer/Counter4. Any output pin actions affect pin OC4B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM4C1 - Compare Output Mode 4C, bit 1

`#define COM4C1_BIT 3`

`#define COM4C1_MASK 8`

The COM4C1 and COM4C0 control bits determine any output pin action following a compare match in Timer/Counter4. Any output pin actions affect pin OC4B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM4B0 - Compare Output Mode 4B, bit 0

`#define COM4B0_BIT 4`

`#define COM4B0_MASK 16`

The COM4B1 and COM4B0 control bits determine any output pin action following a compare match in Timer/Counter4. Any output pin actions affect pin OC4B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM4B1 - Compare Output Mode 4B, bit 1

`#define COM4B1_BIT 5`

`#define COM4B1_MASK 32`

The COM4B1 and COM4B0 control bits determine any output pin action following a compare match in Timer/Counter4. Any output pin actions affect pin OC4B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM4A0 - Compare Output Mode 4A, bit 0

`#define COM4A0_BIT 6`

`#define COM4A0_MASK 64`

The COM4A1 and COM4A0 control bits determine any output pin action following a compare match in Timer/Counter4. Any output pin actions affect pin OC4A - Output CompareA. This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. The control configuration is shown in Table 10.

##### COM4A1 - Compare Output Mode 1A, bit 1

`#define COM4A1_BIT 7`

`#define COM4A1_MASK 128`

The COM4A1 and COM4A0 control bits determine any output pin action following a compare match in Timer/Counter4. Any output pin actions affect pin OC4A - Output CompareA. This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. The control configuration is shown in Table 10.

### TCCR4B - Timer/Counter4 Control Register B

`sfrb TCCR4B = $A1;`

##### CS40 - Prescaler source of Timer/Counter 4

`#define CS40_BIT 0`

`#define CS40_MASK 1`

Select Prescaling Clock Source of Timer/Counter4. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T1, falling edge. (1:1:1) = External Pin 1, rising edge.

##### CS41 - Prescaler source of Timer/Counter 4

`#define CS41_BIT 1`

`#define CS41_MASK 2`

Select Prescaling Clock Source of Timer/Counter4. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T4, falling edge. (1:1:1) = External Pin 1, rising edge.

##### CS42 - Prescaler source of Timer/Counter 4

`#define CS42_BIT 2`

`#define CS42_MASK 4`

Select Prescaling Clock Source of Timer/Counter4. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T4, falling edge. (1:1:1) = External Pin 1, rising edge.

##### WGM42 - Waveform Generation Mode

`#define WGM42_BIT 3`

`#define WGM42_MASK 8`

Combined with the WGM43:2 bits found in the TCCR4B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### WGM43 - Waveform Generation Mode

`#define WGM43_BIT 4`

`#define WGM43_MASK 16`

Combined with the WGM43:2 bits found in the TCCR4B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### ICES4 - Input Capture 4 Edge Select

`#define ICES4_BIT 6`

`#define ICES4_MASK 64`

While the ICES4 bit is cleared (zero), the Timer/Counter4 contents are transferred to the Input Capture Register - ICR4 - on the falling edge of the input capture pin - ICP. While the ICES4 bit is set (one), the Timer/Counter4 contents are transferred to the Input Capture Register - ICR4 - on the rising edge of the input capture pin - ICP.

##### ICNC4 - Input Capture 4 Noise Canceler

`#define ICNC4_BIT 7`

`#define ICNC4_MASK 128`

When the ICNC4 bit is cleared (zero), the input capture trigger noise canceler function is disabled. The input capture is triggered at the first rising/falling edge sampled on the ICP - input capture pin - as specified. When the ICNC4 bit is set (one), four successive samples are measures on the ICP - input capture pin, and all samples must be high/low according to the input capture trigger specification in the ICES4 bit. The actual sampling frequency is XTAL clock frequency.

### TCCR4C - Timer/Counter 4 Control Register C

`sfrb TCCR4C = $A2;`

##### FOC4C - Force Output Compare 4C

`#define FOC4C_BIT 5`

`#define FOC4C_MASK 32`

Writing a logical one to this bit, forces a change in the compare match output pin PD4 according to the values already set in COM4B1 and COM4B0.If the COM4B1 and COM4B0 bits are written in the same cycle as FOC4B,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM4B1 and COM4B0 happens as if a Compare Match had occurred, but no interrupt is generated. The corresponding I/O pin must be set as an output pin for the FOC4B bit to have effect on the pin. The FOC4B bit will always be read as zero. The setting of the FOC4B bit has no effect in PWM mo

##### FOC4B - Force Output Compare 4B

`#define FOC4B_BIT 6`

`#define FOC4B_MASK 64`

Writing a logical one to this bit, forces a change in the compare match output pin PD4 according to the values already set in COM4B1 and COM4B0.If the COM4B1 and COM4B0 bits are written in the same cycle as FOC4B,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM4B1 and COM4B0 happens as if a Compare Match had occurred, but no interrupt is generated. The corresponding I/O pin must be set as an output pin for the FOC4B bit to have effect on the pin. The FOC4B bit will always be read as zero. The setting of the FOC4B bit has no effect in PWM mo

##### FOC4A - Force Output Compare 4A

`#define FOC4A_BIT 7`

`#define FOC4A_MASK 128`

Writing a logical one to this bit, forces a change in the compare match output pin PD5 according to the values already set in COM4A1 and COM4A0.If the COM4A1 and COM4A0 bits are written in the same cycle as FOC4A,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM4A1 and COM4A0 happens as if a Compare Match had occurred, but no interrupt is generated and it will not clear the timer even if CTC4 in TCCR4B is set. The corresponding I/O pin must be set as an output pin for the FOC4A bit to have effect on the pin. The FOC4A bit will always be read as zero. The setting of the FOC4A bit has no effect in PWM m

### TCNT4H - Timer/Counter4 High Byte

`sfrb TCNT4H = $A5;`

##### TCNT4H0 - Timer/Counter4 High Byte bit 0

`#define TCNT4H0_BIT 0`

`#define TCNT4H0_MASK 1`

##### TCNT4H1 - Timer/Counter4 High Byte bit 1

`#define TCNT4H1_BIT 1`

`#define TCNT4H1_MASK 2`

##### TCNT4H2 - Timer/Counter4 High Byte bit 2

`#define TCNT4H2_BIT 2`

`#define TCNT4H2_MASK 4`

##### TCNT4H3 - Timer/Counter4 High Byte bit 3

`#define TCNT4H3_BIT 3`

`#define TCNT4H3_MASK 8`

##### TCNT4H4 - Timer/Counter4 High Byte bit 4

`#define TCNT4H4_BIT 4`

`#define TCNT4H4_MASK 16`

##### TCNT4H5 - Timer/Counter4 High Byte bit 5

`#define TCNT4H5_BIT 5`

`#define TCNT4H5_MASK 32`

##### TCNT4H6 - Timer/Counter4 High Byte bit 6

`#define TCNT4H6_BIT 6`

`#define TCNT4H6_MASK 64`

##### TCNT4H7 - Timer/Counter4 High Byte bit 7

`#define TCNT4H7_BIT 7`

`#define TCNT4H7_MASK 128`

### TCNT4L - Timer/Counter4 Low Byte

`sfrb TCNT4L = $A4;`

##### TCNT4L0 - Timer/Counter4 Low Byte bit 0

`#define TCNT4L0_BIT 0`

`#define TCNT4L0_MASK 1`

##### TCNT4L1 - Timer/Counter4 Low Byte bit 1

`#define TCNT4L1_BIT 1`

`#define TCNT4L1_MASK 2`

##### TCNT4L2 - Timer/Counter4 Low Byte bit 2

`#define TCNT4L2_BIT 2`

`#define TCNT4L2_MASK 4`

##### TCNT4L3 - Timer/Counter4 Low Byte bit 3

`#define TCNT4L3_BIT 3`

`#define TCNT4L3_MASK 8`

##### TCNT4L4 - Timer/Counter4 Low Byte bit 4

`#define TCNT4L4_BIT 4`

`#define TCNT4L4_MASK 16`

##### TCNT4L5 - Timer/Counter4 Low Byte bit 5

`#define TCNT4L5_BIT 5`

`#define TCNT4L5_MASK 32`

##### TCNT4L6 - Timer/Counter4 Low Byte bit 6

`#define TCNT4L6_BIT 6`

`#define TCNT4L6_MASK 64`

##### TCNT4L7 - Timer/Counter4 Low Byte bit 7

`#define TCNT4L7_BIT 7`

`#define TCNT4L7_MASK 128`

### OCR4AH - Timer/Counter4 Outbut Compare Register A High Byte

`sfrb OCR4AH = $A9;`

##### OCR4AH0 - Timer/Counter4 Outbut Compare Register High Byte bit 0

`#define OCR4AH0_BIT 0`

`#define OCR4AH0_MASK 1`

##### OCR4AH1 - Timer/Counter4 Outbut Compare Register High Byte bit 1

`#define OCR4AH1_BIT 1`

`#define OCR4AH1_MASK 2`

##### OCR4AH2 - Timer/Counter4 Outbut Compare Register High Byte bit 2

`#define OCR4AH2_BIT 2`

`#define OCR4AH2_MASK 4`

##### OCR4AH3 - Timer/Counter4 Outbut Compare Register High Byte bit 3

`#define OCR4AH3_BIT 3`

`#define OCR4AH3_MASK 8`

##### OCR4AH4 - Timer/Counter4 Outbut Compare Register High Byte bit 4

`#define OCR4AH4_BIT 4`

`#define OCR4AH4_MASK 16`

##### OCR4AH5 - Timer/Counter4 Outbut Compare Register High Byte bit 5

`#define OCR4AH5_BIT 5`

`#define OCR4AH5_MASK 32`

##### OCR4AH6 - Timer/Counter4 Outbut Compare Register High Byte bit 6

`#define OCR4AH6_BIT 6`

`#define OCR4AH6_MASK 64`

##### OCR4AH7 - Timer/Counter4 Outbut Compare Register High Byte bit 7

`#define OCR4AH7_BIT 7`

`#define OCR4AH7_MASK 128`

### OCR4AL - Timer/Counter4 Outbut Compare Register A Low Byte

`sfrb OCR4AL = $A8;`

##### OCR4AL0 - Timer/Counter4 Outbut Compare Register Low Byte Bit 0

`#define OCR4AL0_BIT 0`

`#define OCR4AL0_MASK 1`

##### OCR4AL1 - Timer/Counter4 Outbut Compare Register Low Byte Bit 1

`#define OCR4AL1_BIT 1`

`#define OCR4AL1_MASK 2`

##### OCR4AL2 - Timer/Counter4 Outbut Compare Register Low Byte Bit 2

`#define OCR4AL2_BIT 2`

`#define OCR4AL2_MASK 4`

##### OCR4AL3 - Timer/Counter4 Outbut Compare Register Low Byte Bit 3

`#define OCR4AL3_BIT 3`

`#define OCR4AL3_MASK 8`

##### OCR4AL4 - Timer/Counter4 Outbut Compare Register Low Byte Bit 4

`#define OCR4AL4_BIT 4`

`#define OCR4AL4_MASK 16`

##### OCR4AL5 - Timer/Counter4 Outbut Compare Register Low Byte Bit 5

`#define OCR4AL5_BIT 5`

`#define OCR4AL5_MASK 32`

##### OCR4AL6 - Timer/Counter4 Outbut Compare Register Low Byte Bit 6

`#define OCR4AL6_BIT 6`

`#define OCR4AL6_MASK 64`

##### OCR4AL7 - Timer/Counter4 Outbut Compare Register Low Byte Bit 7

`#define OCR4AL7_BIT 7`

`#define OCR4AL7_MASK 128`

### OCR4BH - Timer/Counter4 Output Compare Register B High Byte

`sfrb OCR4BH = $AB;`

##### OCR4BH0 - Timer/Counter4 Output Compare Register High Byte bit 0

`#define OCR4BH0_BIT 0`

`#define OCR4BH0_MASK 1`

##### OCR4BH1 - Timer/Counter4 Output Compare Register High Byte bit 1

`#define OCR4BH1_BIT 1`

`#define OCR4BH1_MASK 2`

##### OCR4BH2 - Timer/Counter4 Output Compare Register High Byte bit 2

`#define OCR4BH2_BIT 2`

`#define OCR4BH2_MASK 4`

##### OCR4BH3 - Timer/Counter4 Output Compare Register High Byte bit 3

`#define OCR4BH3_BIT 3`

`#define OCR4BH3_MASK 8`

##### OCR4BH4 - Timer/Counter4 Output Compare Register High Byte bit 4

`#define OCR4BH4_BIT 4`

`#define OCR4BH4_MASK 16`

##### OCR4BH5 - Timer/Counter4 Output Compare Register High Byte bit 5

`#define OCR4BH5_BIT 5`

`#define OCR4BH5_MASK 32`

##### OCR4BH6 - Timer/Counter4 Output Compare Register High Byte bit 6

`#define OCR4BH6_BIT 6`

`#define OCR4BH6_MASK 64`

##### OCR4BH7 - Timer/Counter4 Output Compare Register High Byte bit 7

`#define OCR4BH7_BIT 7`

`#define OCR4BH7_MASK 128`

### OCR4BL - Timer/Counter4 Output Compare Register B Low Byte

`sfrb OCR4BL = $AA;`

##### OCR4BL0 - Timer/Counter4 Output Compare Register Low Byte bit 0

`#define OCR4BL0_BIT 0`

`#define OCR4BL0_MASK 1`

##### OCR4BL1 - Timer/Counter4 Output Compare Register Low Byte bit 1

`#define OCR4BL1_BIT 1`

`#define OCR4BL1_MASK 2`

##### OCR4BL2 - Timer/Counter4 Output Compare Register Low Byte bit 2

`#define OCR4BL2_BIT 2`

`#define OCR4BL2_MASK 4`

##### OCR4BL3 - Timer/Counter4 Output Compare Register Low Byte bit 3

`#define OCR4BL3_BIT 3`

`#define OCR4BL3_MASK 8`

##### OCR4BL4 - Timer/Counter4 Output Compare Register Low Byte bit 4

`#define OCR4BL4_BIT 4`

`#define OCR4BL4_MASK 16`

##### OCR4BL5 - Timer/Counter4 Output Compare Register Low Byte bit 5

`#define OCR4BL5_BIT 5`

`#define OCR4BL5_MASK 32`

##### OCR4BL6 - Timer/Counter4 Output Compare Register Low Byte bit 6

`#define OCR4BL6_BIT 6`

`#define OCR4BL6_MASK 64`

##### OCR4BL7 - Timer/Counter4 Output Compare Register Low Byte bit 7

`#define OCR4BL7_BIT 7`

`#define OCR4BL7_MASK 128`

### OCR4CH - Timer/Counter4 Output Compare Register B High Byte

`sfrb OCR4CH = $AD;`

##### OCR4CH0 - Timer/Counter4 Output Compare Register High Byte bit 0

`#define OCR4CH0_BIT 0`

`#define OCR4CH0_MASK 1`

##### OCR4CH1 - Timer/Counter4 Output Compare Register High Byte bit 1

`#define OCR4CH1_BIT 1`

`#define OCR4CH1_MASK 2`

##### OCR4CH2 - Timer/Counter4 Output Compare Register High Byte bit 2

`#define OCR4CH2_BIT 2`

`#define OCR4CH2_MASK 4`

##### OCR4CH3 - Timer/Counter4 Output Compare Register High Byte bit 3

`#define OCR4CH3_BIT 3`

`#define OCR4CH3_MASK 8`

##### OCR4CH4 - Timer/Counter4 Output Compare Register High Byte bit 4

`#define OCR4CH4_BIT 4`

`#define OCR4CH4_MASK 16`

##### OCR4CH5 - Timer/Counter4 Output Compare Register High Byte bit 5

`#define OCR4CH5_BIT 5`

`#define OCR4CH5_MASK 32`

##### OCR4CH6 - Timer/Counter4 Output Compare Register High Byte bit 6

`#define OCR4CH6_BIT 6`

`#define OCR4CH6_MASK 64`

##### OCR4CH7 - Timer/Counter4 Output Compare Register High Byte bit 7

`#define OCR4CH7_BIT 7`

`#define OCR4CH7_MASK 128`

### OCR4CL - Timer/Counter4 Output Compare Register B Low Byte

`sfrb OCR4CL = $AC;`

##### OCR4CL0 - Timer/Counter4 Output Compare Register Low Byte bit 0

`#define OCR4CL0_BIT 0`

`#define OCR4CL0_MASK 1`

##### OCR4CL1 - Timer/Counter4 Output Compare Register Low Byte bit 1

`#define OCR4CL1_BIT 1`

`#define OCR4CL1_MASK 2`

##### OCR4CL2 - Timer/Counter4 Output Compare Register Low Byte bit 2

`#define OCR4CL2_BIT 2`

`#define OCR4CL2_MASK 4`

##### OCR4CL3 - Timer/Counter4 Output Compare Register Low Byte bit 3

`#define OCR4CL3_BIT 3`

`#define OCR4CL3_MASK 8`

##### OCR4CL4 - Timer/Counter4 Output Compare Register Low Byte bit 4

`#define OCR4CL4_BIT 4`

`#define OCR4CL4_MASK 16`

##### OCR4CL5 - Timer/Counter4 Output Compare Register Low Byte bit 5

`#define OCR4CL5_BIT 5`

`#define OCR4CL5_MASK 32`

##### OCR4CL6 - Timer/Counter4 Output Compare Register Low Byte bit 6

`#define OCR4CL6_BIT 6`

`#define OCR4CL6_MASK 64`

##### OCR4CL7 - Timer/Counter4 Output Compare Register Low Byte bit 7

`#define OCR4CL7_BIT 7`

`#define OCR4CL7_MASK 128`

### ICR4H - Timer/Counter4 Input Capture Register High Byte

`sfrb ICR4H = $A7;`

##### ICR4H0 - Timer/Counter4 Input Capture Register High Byte bit 0

`#define ICR4H0_BIT 0`

`#define ICR4H0_MASK 1`

##### ICR4H1 - Timer/Counter4 Input Capture Register High Byte bit 1

`#define ICR4H1_BIT 1`

`#define ICR4H1_MASK 2`

##### ICR4H2 - Timer/Counter4 Input Capture Register High Byte bit 2

`#define ICR4H2_BIT 2`

`#define ICR4H2_MASK 4`

##### ICR4H3 - Timer/Counter4 Input Capture Register High Byte bit 3

`#define ICR4H3_BIT 3`

`#define ICR4H3_MASK 8`

##### ICR4H4 - Timer/Counter4 Input Capture Register High Byte bit 4

`#define ICR4H4_BIT 4`

`#define ICR4H4_MASK 16`

##### ICR4H5 - Timer/Counter4 Input Capture Register High Byte bit 5

`#define ICR4H5_BIT 5`

`#define ICR4H5_MASK 32`

##### ICR4H6 - Timer/Counter4 Input Capture Register High Byte bit 6

`#define ICR4H6_BIT 6`

`#define ICR4H6_MASK 64`

##### ICR4H7 - Timer/Counter4 Input Capture Register High Byte bit 7

`#define ICR4H7_BIT 7`

`#define ICR4H7_MASK 128`

### ICR4L - Timer/Counter4 Input Capture Register Low Byte

`sfrb ICR4L = $A6;`

##### ICR4L0 - Timer/Counter4 Input Capture Register Low Byte bit 0

`#define ICR4L0_BIT 0`

`#define ICR4L0_MASK 1`

##### ICR4L1 - Timer/Counter4 Input Capture Register Low Byte bit 1

`#define ICR4L1_BIT 1`

`#define ICR4L1_MASK 2`

##### ICR4L2 - Timer/Counter4 Input Capture Register Low Byte bit 2

`#define ICR4L2_BIT 2`

`#define ICR4L2_MASK 4`

##### ICR4L3 - Timer/Counter4 Input Capture Register Low Byte bit 3

`#define ICR4L3_BIT 3`

`#define ICR4L3_MASK 8`

##### ICR4L4 - Timer/Counter4 Input Capture Register Low Byte bit 4

`#define ICR4L4_BIT 4`

`#define ICR4L4_MASK 16`

##### ICR4L5 - Timer/Counter4 Input Capture Register Low Byte bit 5

`#define ICR4L5_BIT 5`

`#define ICR4L5_MASK 32`

##### ICR4L6 - Timer/Counter4 Input Capture Register Low Byte bit 6

`#define ICR4L6_BIT 6`

`#define ICR4L6_MASK 64`

##### ICR4L7 - Timer/Counter4 Input Capture Register Low Byte bit 7

`#define ICR4L7_BIT 7`

`#define ICR4L7_MASK 128`

### TIMSK4 - Timer/Counter4 Interrupt Mask Register

`sfrb TIMSK4 = $72;`

##### TOIE4 - Timer/Counter4 Overflow Interrupt Enable

`#define TOIE4_BIT 0`

`#define TOIE4_MASK 1`

When the TOIE4 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter4 Overflow interrupt is enabled. The corresponding interrupt (at vector $006) is executed if an overflow in Timer/Counter4 occurs, i.e., when the TOV4 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE4A - Timer/Counter4 Output Compare A Match Interrupt Enable

`#define OCIE4A_BIT 1`

`#define OCIE4A_MASK 2`

When the OCIE4A bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter4 CompareA Match interrupt is enabled. The corresponding interrupt (at vector $004) is executed if a CompareA match in Timer/Counter4 occurs, i.e., when the OCF4A bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE4B - Timer/Counter4 Output Compare B Match Interrupt Enable

`#define OCIE4B_BIT 2`

`#define OCIE4B_MASK 4`

When the OCIE4B bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter4 CompareB Match interrupt is enabled. The corresponding interrupt (at vector $005) is executed if a CompareB match in Timer/Counter4 occurs, i.e., when the OCF4B bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE4C - Timer/Counter4 Output Compare C Match Interrupt Enable

`#define OCIE4C_BIT 3`

`#define OCIE4C_MASK 8`

When the OCIE4C bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter4 CompareB Match interrupt is enabled. The corresponding interrupt (at vector $005) is executed if a CompareB match in Timer/Counter4 occurs, i.e., when the OCF4B bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### ICIE4 - Timer/Counter4 Input Capture Interrupt Enable

`#define ICIE4_BIT 5`

`#define ICIE4_MASK 32`

When the TICIE4 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter4 Input Capture Event Interrupt is enabled. The corresponding interrupt (at vector $003) is executed if a capture-triggering event occurs on pin 31, ICP, i.e., when the ICF4 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

### TIFR4 - Timer/Counter4 Interrupt Flag register

`sfrb TIFR4 = $19;`

##### TOV4 - Timer/Counter4 Overflow Flag

`#define TOV4_BIT 0`

`#define TOV4_MASK 1`

The TOV4 is set (one) when an overflow occurs in Timer/Counter4. TOV4 is cleared by hardware when executing the cor-responding interrupt handling vector. Alternatively, TOV4 is cleared by writing a logic one to the flag. When the I-bit in SREG, and TOIE4 (Timer/Counter4 Overflow Interrupt Enable), and TOV4 are set (one), the Timer/Counter4 Overflow Interrupt is executed. In PWM mode, this bit is set when Timer/Counter4 changes counting direction at $0000.

##### OCF4A - Output Compare Flag 4A

`#define OCF4A_BIT 1`

`#define OCF4A_MASK 2`

The OCF4A bit is set (one) when compare match occurs between the Timer/Counter4 and the data in OCR4A - Output Compare Register 4A. OCF4A is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF4A is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE4A (Timer/Counter4 Compare match InterruptA Enable), and the OCF4A are set (one), the Timer/Counter4 Compare A match Interrupt is executed.

##### OCF4B - Output Compare Flag 4B

`#define OCF4B_BIT 2`

`#define OCF4B_MASK 4`

The OCF4B bit is set (one) when compare match occurs between the Timer/Counter4 and the data in OCR4B - Output Compare Register 4B. OCF4B is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF4B is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE4B (Timer/Counter4 Compare match InterruptB Enable), and the OCF4B are set (one), the Timer/Counter4 Compare B match Interrupt is executed.

##### OCF4C - Output Compare Flag 4C

`#define OCF4C_BIT 3`

`#define OCF4C_MASK 8`

The OCF4C bit is set (one) when compare match occurs between the Timer/Counter4 and the data in OCR4B - Output Compare Register 4B. OCF4B is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF4B is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE4B (Timer/Counter4 Compare match InterruptB Enable), and the OCF4B are set (one), the Timer/Counter4 Compare B match Interrupt is executed.

##### ICF4 - Input Capture Flag 4

`#define ICF4_BIT 5`

`#define ICF4_MASK 32`

The ICF4 bit is set (one) to flag an input capture event, indicating that the Timer/Counter4 value has been transferred to the input capture register - ICR4. ICF4 is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, ICF4 is cleared by writing a logic one to the flag. When the SREG I-bit, and TICIE4 (Timer/Counter4 Input Capture Interrupt Enable), and ICF4 are set (one), the Timer/Counter4 Capture Interrupt is executed.

## TIMER COUNTER 3

### TCCR3A - Timer/Counter3 Control Register A

`sfrb TCCR3A = $90;`

##### WGM30 - Waveform Generation Mode

`#define WGM30_BIT 0`

`#define WGM30_MASK 1`

Combined with the WGM33:2 bits found in the TCCR3B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### WGM31 - Waveform Generation Mode

`#define WGM31_BIT 1`

`#define WGM31_MASK 2`

Combined with the WGM33:2 bits found in the TCCR3B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### COM3C0 - Compare Output Mode 3C, bit 0

`#define COM3C0_BIT 2`

`#define COM3C0_MASK 4`

The COM3C1 and COM3C0 control bits determine any output pin action following a compare match in Timer/Counter3. Any output pin actions affect pin OC3B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM3C1 - Compare Output Mode 3C, bit 1

`#define COM3C1_BIT 3`

`#define COM3C1_MASK 8`

The COM3C1 and COM3C0 control bits determine any output pin action following a compare match in Timer/Counter3. Any output pin actions affect pin OC3B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM3B0 - Compare Output Mode 3B, bit 0

`#define COM3B0_BIT 4`

`#define COM3B0_MASK 16`

The COM3B1 and COM3B0 control bits determine any output pin action following a compare match in Timer/Counter3. Any output pin actions affect pin OC3B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM3B1 - Compare Output Mode 3B, bit 1

`#define COM3B1_BIT 5`

`#define COM3B1_MASK 32`

The COM3B1 and COM3B0 control bits determine any output pin action following a compare match in Timer/Counter3. Any output pin actions affect pin OC3B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM3A0 - Compare Output Mode 3A, bit 0

`#define COM3A0_BIT 6`

`#define COM3A0_MASK 64`

The COM3A1 and COM3A0 control bits determine any output pin action following a compare match in Timer/Counter3. Any output pin actions affect pin OC3A - Output CompareA. This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. The control configuration is shown in Table 10.

##### COM3A1 - Compare Output Mode 1A, bit 1

`#define COM3A1_BIT 7`

`#define COM3A1_MASK 128`

The COM3A1 and COM3A0 control bits determine any output pin action following a compare match in Timer/Counter3. Any output pin actions affect pin OC3A - Output CompareA. This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. The control configuration is shown in Table 10.

### TCCR3B - Timer/Counter3 Control Register B

`sfrb TCCR3B = $91;`

##### CS30 - Prescaler source of Timer/Counter 3

`#define CS30_BIT 0`

`#define CS30_MASK 1`

Select Prescaling Clock Source of Timer/Counter3. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T1, falling edge. (1:1:1) = External Pin 1, rising edge.

##### CS31 - Prescaler source of Timer/Counter 3

`#define CS31_BIT 1`

`#define CS31_MASK 2`

Select Prescaling Clock Source of Timer/Counter3. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T3, falling edge. (1:1:1) = External Pin 1, rising edge.

##### CS32 - Prescaler source of Timer/Counter 3

`#define CS32_BIT 2`

`#define CS32_MASK 4`

Select Prescaling Clock Source of Timer/Counter3. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T3, falling edge. (1:1:1) = External Pin 1, rising edge.

##### WGM32 - Waveform Generation Mode

`#define WGM32_BIT 3`

`#define WGM32_MASK 8`

Combined with the WGM33:2 bits found in the TCCR3B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### WGM33 - Waveform Generation Mode

`#define WGM33_BIT 4`

`#define WGM33_MASK 16`

Combined with the WGM33:2 bits found in the TCCR3B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### ICES3 - Input Capture 3 Edge Select

`#define ICES3_BIT 6`

`#define ICES3_MASK 64`

While the ICES3 bit is cleared (zero), the Timer/Counter3 contents are transferred to the Input Capture Register - ICR3 - on the falling edge of the input capture pin - ICP. While the ICES3 bit is set (one), the Timer/Counter3 contents are transferred to the Input Capture Register - ICR3 - on the rising edge of the input capture pin - ICP.

##### ICNC3 - Input Capture 3 Noise Canceler

`#define ICNC3_BIT 7`

`#define ICNC3_MASK 128`

When the ICNC3 bit is cleared (zero), the input capture trigger noise canceler function is disabled. The input capture is triggered at the first rising/falling edge sampled on the ICP - input capture pin - as specified. When the ICNC3 bit is set (one), four successive samples are measures on the ICP - input capture pin, and all samples must be high/low according to the input capture trigger specification in the ICES3 bit. The actual sampling frequency is XTAL clock frequency.

### TCCR3C - Timer/Counter 3 Control Register C

`sfrb TCCR3C = $92;`

##### FOC3C - Force Output Compare 3C

`#define FOC3C_BIT 5`

`#define FOC3C_MASK 32`

Writing a logical one to this bit, forces a change in the compare match output pin PD4 according to the values already set in COM3B1 and COM3B0.If the COM3B1 and COM3B0 bits are written in the same cycle as FOC3B,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM3B1 and COM3B0 happens as if a Compare Match had occurred, but no interrupt is generated. The corresponding I/O pin must be set as an output pin for the FOC3B bit to have effect on the pin. The FOC3B bit will always be read as zero. The setting of the FOC3B bit has no effect in PWM mo

##### FOC3B - Force Output Compare 3B

`#define FOC3B_BIT 6`

`#define FOC3B_MASK 64`

Writing a logical one to this bit, forces a change in the compare match output pin PD4 according to the values already set in COM3B1 and COM3B0.If the COM3B1 and COM3B0 bits are written in the same cycle as FOC3B,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM3B1 and COM3B0 happens as if a Compare Match had occurred, but no interrupt is generated. The corresponding I/O pin must be set as an output pin for the FOC3B bit to have effect on the pin. The FOC3B bit will always be read as zero. The setting of the FOC3B bit has no effect in PWM mo

##### FOC3A - Force Output Compare 3A

`#define FOC3A_BIT 7`

`#define FOC3A_MASK 128`

Writing a logical one to this bit, forces a change in the compare match output pin PD5 according to the values already set in COM3A1 and COM3A0.If the COM3A1 and COM3A0 bits are written in the same cycle as FOC3A,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM3A1 and COM3A0 happens as if a Compare Match had occurred, but no interrupt is generated and it will not clear the timer even if CTC3 in TCCR3B is set. The corresponding I/O pin must be set as an output pin for the FOC3A bit to have effect on the pin. The FOC3A bit will always be read as zero. The setting of the FOC3A bit has no effect in PWM m

### TCNT3H - Timer/Counter3 High Byte

`sfrb TCNT3H = $95;`

##### TCNT3H0 - Timer/Counter3 High Byte bit 0

`#define TCNT3H0_BIT 0`

`#define TCNT3H0_MASK 1`

##### TCNT3H1 - Timer/Counter3 High Byte bit 1

`#define TCNT3H1_BIT 1`

`#define TCNT3H1_MASK 2`

##### TCNT3H2 - Timer/Counter3 High Byte bit 2

`#define TCNT3H2_BIT 2`

`#define TCNT3H2_MASK 4`

##### TCNT3H3 - Timer/Counter3 High Byte bit 3

`#define TCNT3H3_BIT 3`

`#define TCNT3H3_MASK 8`

##### TCNT3H4 - Timer/Counter3 High Byte bit 4

`#define TCNT3H4_BIT 4`

`#define TCNT3H4_MASK 16`

##### TCNT3H5 - Timer/Counter3 High Byte bit 5

`#define TCNT3H5_BIT 5`

`#define TCNT3H5_MASK 32`

##### TCNT3H6 - Timer/Counter3 High Byte bit 6

`#define TCNT3H6_BIT 6`

`#define TCNT3H6_MASK 64`

##### TCNT3H7 - Timer/Counter3 High Byte bit 7

`#define TCNT3H7_BIT 7`

`#define TCNT3H7_MASK 128`

### TCNT3L - Timer/Counter3 Low Byte

`sfrb TCNT3L = $94;`

##### TCNT3L0 - Timer/Counter3 Low Byte bit 0

`#define TCNT3L0_BIT 0`

`#define TCNT3L0_MASK 1`

##### TCNT3L1 - Timer/Counter3 Low Byte bit 1

`#define TCNT3L1_BIT 1`

`#define TCNT3L1_MASK 2`

##### TCNT3L2 - Timer/Counter3 Low Byte bit 2

`#define TCNT3L2_BIT 2`

`#define TCNT3L2_MASK 4`

##### TCNT3L3 - Timer/Counter3 Low Byte bit 3

`#define TCNT3L3_BIT 3`

`#define TCNT3L3_MASK 8`

##### TCNT3L4 - Timer/Counter3 Low Byte bit 4

`#define TCNT3L4_BIT 4`

`#define TCNT3L4_MASK 16`

##### TCNT3L5 - Timer/Counter3 Low Byte bit 5

`#define TCNT3L5_BIT 5`

`#define TCNT3L5_MASK 32`

##### TCNT3L6 - Timer/Counter3 Low Byte bit 6

`#define TCNT3L6_BIT 6`

`#define TCNT3L6_MASK 64`

##### TCNT3L7 - Timer/Counter3 Low Byte bit 7

`#define TCNT3L7_BIT 7`

`#define TCNT3L7_MASK 128`

### OCR3AH - Timer/Counter3 Outbut Compare Register A High Byte

`sfrb OCR3AH = $99;`

##### OCR3AH0 - Timer/Counter3 Outbut Compare Register High Byte bit 0

`#define OCR3AH0_BIT 0`

`#define OCR3AH0_MASK 1`

##### OCR3AH1 - Timer/Counter3 Outbut Compare Register High Byte bit 1

`#define OCR3AH1_BIT 1`

`#define OCR3AH1_MASK 2`

##### OCR3AH2 - Timer/Counter3 Outbut Compare Register High Byte bit 2

`#define OCR3AH2_BIT 2`

`#define OCR3AH2_MASK 4`

##### OCR3AH3 - Timer/Counter3 Outbut Compare Register High Byte bit 3

`#define OCR3AH3_BIT 3`

`#define OCR3AH3_MASK 8`

##### OCR3AH4 - Timer/Counter3 Outbut Compare Register High Byte bit 4

`#define OCR3AH4_BIT 4`

`#define OCR3AH4_MASK 16`

##### OCR3AH5 - Timer/Counter3 Outbut Compare Register High Byte bit 5

`#define OCR3AH5_BIT 5`

`#define OCR3AH5_MASK 32`

##### OCR3AH6 - Timer/Counter3 Outbut Compare Register High Byte bit 6

`#define OCR3AH6_BIT 6`

`#define OCR3AH6_MASK 64`

##### OCR3AH7 - Timer/Counter3 Outbut Compare Register High Byte bit 7

`#define OCR3AH7_BIT 7`

`#define OCR3AH7_MASK 128`

### OCR3AL - Timer/Counter3 Outbut Compare Register A Low Byte

`sfrb OCR3AL = $98;`

##### OCR3AL0 - Timer/Counter3 Outbut Compare Register Low Byte Bit 0

`#define OCR3AL0_BIT 0`

`#define OCR3AL0_MASK 1`

##### OCR3AL1 - Timer/Counter3 Outbut Compare Register Low Byte Bit 1

`#define OCR3AL1_BIT 1`

`#define OCR3AL1_MASK 2`

##### OCR3AL2 - Timer/Counter3 Outbut Compare Register Low Byte Bit 2

`#define OCR3AL2_BIT 2`

`#define OCR3AL2_MASK 4`

##### OCR3AL3 - Timer/Counter3 Outbut Compare Register Low Byte Bit 3

`#define OCR3AL3_BIT 3`

`#define OCR3AL3_MASK 8`

##### OCR3AL4 - Timer/Counter3 Outbut Compare Register Low Byte Bit 4

`#define OCR3AL4_BIT 4`

`#define OCR3AL4_MASK 16`

##### OCR3AL5 - Timer/Counter3 Outbut Compare Register Low Byte Bit 5

`#define OCR3AL5_BIT 5`

`#define OCR3AL5_MASK 32`

##### OCR3AL6 - Timer/Counter3 Outbut Compare Register Low Byte Bit 6

`#define OCR3AL6_BIT 6`

`#define OCR3AL6_MASK 64`

##### OCR3AL7 - Timer/Counter3 Outbut Compare Register Low Byte Bit 7

`#define OCR3AL7_BIT 7`

`#define OCR3AL7_MASK 128`

### OCR3BH - Timer/Counter3 Output Compare Register B High Byte

`sfrb OCR3BH = $9B;`

##### OCR3BH0 - Timer/Counter3 Output Compare Register High Byte bit 0

`#define OCR3BH0_BIT 0`

`#define OCR3BH0_MASK 1`

##### OCR3BH1 - Timer/Counter3 Output Compare Register High Byte bit 1

`#define OCR3BH1_BIT 1`

`#define OCR3BH1_MASK 2`

##### OCR3BH2 - Timer/Counter3 Output Compare Register High Byte bit 2

`#define OCR3BH2_BIT 2`

`#define OCR3BH2_MASK 4`

##### OCR3BH3 - Timer/Counter3 Output Compare Register High Byte bit 3

`#define OCR3BH3_BIT 3`

`#define OCR3BH3_MASK 8`

##### OCR3BH4 - Timer/Counter3 Output Compare Register High Byte bit 4

`#define OCR3BH4_BIT 4`

`#define OCR3BH4_MASK 16`

##### OCR3BH5 - Timer/Counter3 Output Compare Register High Byte bit 5

`#define OCR3BH5_BIT 5`

`#define OCR3BH5_MASK 32`

##### OCR3BH6 - Timer/Counter3 Output Compare Register High Byte bit 6

`#define OCR3BH6_BIT 6`

`#define OCR3BH6_MASK 64`

##### OCR3BH7 - Timer/Counter3 Output Compare Register High Byte bit 7

`#define OCR3BH7_BIT 7`

`#define OCR3BH7_MASK 128`

### OCR3BL - Timer/Counter3 Output Compare Register B Low Byte

`sfrb OCR3BL = $9A;`

##### OCR3BL0 - Timer/Counter3 Output Compare Register Low Byte bit 0

`#define OCR3BL0_BIT 0`

`#define OCR3BL0_MASK 1`

##### OCR3BL1 - Timer/Counter3 Output Compare Register Low Byte bit 1

`#define OCR3BL1_BIT 1`

`#define OCR3BL1_MASK 2`

##### OCR3BL2 - Timer/Counter3 Output Compare Register Low Byte bit 2

`#define OCR3BL2_BIT 2`

`#define OCR3BL2_MASK 4`

##### OCR3BL3 - Timer/Counter3 Output Compare Register Low Byte bit 3

`#define OCR3BL3_BIT 3`

`#define OCR3BL3_MASK 8`

##### OCR3BL4 - Timer/Counter3 Output Compare Register Low Byte bit 4

`#define OCR3BL4_BIT 4`

`#define OCR3BL4_MASK 16`

##### OCR3BL5 - Timer/Counter3 Output Compare Register Low Byte bit 5

`#define OCR3BL5_BIT 5`

`#define OCR3BL5_MASK 32`

##### OCR3BL6 - Timer/Counter3 Output Compare Register Low Byte bit 6

`#define OCR3BL6_BIT 6`

`#define OCR3BL6_MASK 64`

##### OCR3BL7 - Timer/Counter3 Output Compare Register Low Byte bit 7

`#define OCR3BL7_BIT 7`

`#define OCR3BL7_MASK 128`

### OCR3CH - Timer/Counter3 Output Compare Register B High Byte

`sfrb OCR3CH = $9D;`

##### OCR3CH0 - Timer/Counter3 Output Compare Register High Byte bit 0

`#define OCR3CH0_BIT 0`

`#define OCR3CH0_MASK 1`

##### OCR3CH1 - Timer/Counter3 Output Compare Register High Byte bit 1

`#define OCR3CH1_BIT 1`

`#define OCR3CH1_MASK 2`

##### OCR3CH2 - Timer/Counter3 Output Compare Register High Byte bit 2

`#define OCR3CH2_BIT 2`

`#define OCR3CH2_MASK 4`

##### OCR3CH3 - Timer/Counter3 Output Compare Register High Byte bit 3

`#define OCR3CH3_BIT 3`

`#define OCR3CH3_MASK 8`

##### OCR3CH4 - Timer/Counter3 Output Compare Register High Byte bit 4

`#define OCR3CH4_BIT 4`

`#define OCR3CH4_MASK 16`

##### OCR3CH5 - Timer/Counter3 Output Compare Register High Byte bit 5

`#define OCR3CH5_BIT 5`

`#define OCR3CH5_MASK 32`

##### OCR3CH6 - Timer/Counter3 Output Compare Register High Byte bit 6

`#define OCR3CH6_BIT 6`

`#define OCR3CH6_MASK 64`

##### OCR3CH7 - Timer/Counter3 Output Compare Register High Byte bit 7

`#define OCR3CH7_BIT 7`

`#define OCR3CH7_MASK 128`

### OCR3CL - Timer/Counter3 Output Compare Register B Low Byte

`sfrb OCR3CL = $9C;`

##### OCR3CL0 - Timer/Counter3 Output Compare Register Low Byte bit 0

`#define OCR3CL0_BIT 0`

`#define OCR3CL0_MASK 1`

##### OCR3CL1 - Timer/Counter3 Output Compare Register Low Byte bit 1

`#define OCR3CL1_BIT 1`

`#define OCR3CL1_MASK 2`

##### OCR3CL2 - Timer/Counter3 Output Compare Register Low Byte bit 2

`#define OCR3CL2_BIT 2`

`#define OCR3CL2_MASK 4`

##### OCR3CL3 - Timer/Counter3 Output Compare Register Low Byte bit 3

`#define OCR3CL3_BIT 3`

`#define OCR3CL3_MASK 8`

##### OCR3CL4 - Timer/Counter3 Output Compare Register Low Byte bit 4

`#define OCR3CL4_BIT 4`

`#define OCR3CL4_MASK 16`

##### OCR3CL5 - Timer/Counter3 Output Compare Register Low Byte bit 5

`#define OCR3CL5_BIT 5`

`#define OCR3CL5_MASK 32`

##### OCR3CL6 - Timer/Counter3 Output Compare Register Low Byte bit 6

`#define OCR3CL6_BIT 6`

`#define OCR3CL6_MASK 64`

##### OCR3CL7 - Timer/Counter3 Output Compare Register Low Byte bit 7

`#define OCR3CL7_BIT 7`

`#define OCR3CL7_MASK 128`

### ICR3H - Timer/Counter3 Input Capture Register High Byte

`sfrb ICR3H = $97;`

##### ICR3H0 - Timer/Counter3 Input Capture Register High Byte bit 0

`#define ICR3H0_BIT 0`

`#define ICR3H0_MASK 1`

##### ICR3H1 - Timer/Counter3 Input Capture Register High Byte bit 1

`#define ICR3H1_BIT 1`

`#define ICR3H1_MASK 2`

##### ICR3H2 - Timer/Counter3 Input Capture Register High Byte bit 2

`#define ICR3H2_BIT 2`

`#define ICR3H2_MASK 4`

##### ICR3H3 - Timer/Counter3 Input Capture Register High Byte bit 3

`#define ICR3H3_BIT 3`

`#define ICR3H3_MASK 8`

##### ICR3H4 - Timer/Counter3 Input Capture Register High Byte bit 4

`#define ICR3H4_BIT 4`

`#define ICR3H4_MASK 16`

##### ICR3H5 - Timer/Counter3 Input Capture Register High Byte bit 5

`#define ICR3H5_BIT 5`

`#define ICR3H5_MASK 32`

##### ICR3H6 - Timer/Counter3 Input Capture Register High Byte bit 6

`#define ICR3H6_BIT 6`

`#define ICR3H6_MASK 64`

##### ICR3H7 - Timer/Counter3 Input Capture Register High Byte bit 7

`#define ICR3H7_BIT 7`

`#define ICR3H7_MASK 128`

### ICR3L - Timer/Counter3 Input Capture Register Low Byte

`sfrb ICR3L = $96;`

##### ICR3L0 - Timer/Counter3 Input Capture Register Low Byte bit 0

`#define ICR3L0_BIT 0`

`#define ICR3L0_MASK 1`

##### ICR3L1 - Timer/Counter3 Input Capture Register Low Byte bit 1

`#define ICR3L1_BIT 1`

`#define ICR3L1_MASK 2`

##### ICR3L2 - Timer/Counter3 Input Capture Register Low Byte bit 2

`#define ICR3L2_BIT 2`

`#define ICR3L2_MASK 4`

##### ICR3L3 - Timer/Counter3 Input Capture Register Low Byte bit 3

`#define ICR3L3_BIT 3`

`#define ICR3L3_MASK 8`

##### ICR3L4 - Timer/Counter3 Input Capture Register Low Byte bit 4

`#define ICR3L4_BIT 4`

`#define ICR3L4_MASK 16`

##### ICR3L5 - Timer/Counter3 Input Capture Register Low Byte bit 5

`#define ICR3L5_BIT 5`

`#define ICR3L5_MASK 32`

##### ICR3L6 - Timer/Counter3 Input Capture Register Low Byte bit 6

`#define ICR3L6_BIT 6`

`#define ICR3L6_MASK 64`

##### ICR3L7 - Timer/Counter3 Input Capture Register Low Byte bit 7

`#define ICR3L7_BIT 7`

`#define ICR3L7_MASK 128`

### TIMSK3 - Timer/Counter3 Interrupt Mask Register

`sfrb TIMSK3 = $71;`

##### TOIE3 - Timer/Counter3 Overflow Interrupt Enable

`#define TOIE3_BIT 0`

`#define TOIE3_MASK 1`

When the TOIE3 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter3 Overflow interrupt is enabled. The corresponding interrupt (at vector $006) is executed if an overflow in Timer/Counter3 occurs, i.e., when the TOV3 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE3A - Timer/Counter3 Output Compare A Match Interrupt Enable

`#define OCIE3A_BIT 1`

`#define OCIE3A_MASK 2`

When the OCIE3A bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter3 CompareA Match interrupt is enabled. The corresponding interrupt (at vector $004) is executed if a CompareA match in Timer/Counter3 occurs, i.e., when the OCF3A bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE3B - Timer/Counter3 Output Compare B Match Interrupt Enable

`#define OCIE3B_BIT 2`

`#define OCIE3B_MASK 4`

When the OCIE3B bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter3 CompareB Match interrupt is enabled. The corresponding interrupt (at vector $005) is executed if a CompareB match in Timer/Counter3 occurs, i.e., when the OCF3B bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE3C - Timer/Counter3 Output Compare C Match Interrupt Enable

`#define OCIE3C_BIT 3`

`#define OCIE3C_MASK 8`

When the OCIE3C bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter3 CompareB Match interrupt is enabled. The corresponding interrupt (at vector $005) is executed if a CompareB match in Timer/Counter3 occurs, i.e., when the OCF3B bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### ICIE3 - Timer/Counter3 Input Capture Interrupt Enable

`#define ICIE3_BIT 5`

`#define ICIE3_MASK 32`

When the TICIE3 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter3 Input Capture Event Interrupt is enabled. The corresponding interrupt (at vector $003) is executed if a capture-triggering event occurs on pin 31, ICP, i.e., when the ICF3 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

### TIFR3 - Timer/Counter3 Interrupt Flag register

`sfrb TIFR3 = $18;`

##### TOV3 - Timer/Counter3 Overflow Flag

`#define TOV3_BIT 0`

`#define TOV3_MASK 1`

The TOV3 is set (one) when an overflow occurs in Timer/Counter3. TOV3 is cleared by hardware when executing the cor-responding interrupt handling vector. Alternatively, TOV3 is cleared by writing a logic one to the flag. When the I-bit in SREG, and TOIE3 (Timer/Counter3 Overflow Interrupt Enable), and TOV3 are set (one), the Timer/Counter3 Overflow Interrupt is executed. In PWM mode, this bit is set when Timer/Counter3 changes counting direction at $0000.

##### OCF3A - Output Compare Flag 3A

`#define OCF3A_BIT 1`

`#define OCF3A_MASK 2`

The OCF3A bit is set (one) when compare match occurs between the Timer/Counter3 and the data in OCR3A - Output Compare Register 3A. OCF3A is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF3A is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE3A (Timer/Counter3 Compare match InterruptA Enable), and the OCF3A are set (one), the Timer/Counter3 Compare A match Interrupt is executed.

##### OCF3B - Output Compare Flag 3B

`#define OCF3B_BIT 2`

`#define OCF3B_MASK 4`

The OCF3B bit is set (one) when compare match occurs between the Timer/Counter3 and the data in OCR3B - Output Compare Register 3B. OCF3B is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF3B is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE3B (Timer/Counter3 Compare match InterruptB Enable), and the OCF3B are set (one), the Timer/Counter3 Compare B match Interrupt is executed.

##### OCF3C - Output Compare Flag 3C

`#define OCF3C_BIT 3`

`#define OCF3C_MASK 8`

The OCF3C bit is set (one) when compare match occurs between the Timer/Counter3 and the data in OCR3B - Output Compare Register 3B. OCF3B is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF3B is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE3B (Timer/Counter3 Compare match InterruptB Enable), and the OCF3B are set (one), the Timer/Counter3 Compare B match Interrupt is executed.

##### ICF3 - Input Capture Flag 3

`#define ICF3_BIT 5`

`#define ICF3_MASK 32`

The ICF3 bit is set (one) to flag an input capture event, indicating that the Timer/Counter3 value has been transferred to the input capture register - ICR3. ICF3 is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, ICF3 is cleared by writing a logic one to the flag. When the SREG I-bit, and TICIE3 (Timer/Counter3 Input Capture Interrupt Enable), and ICF3 are set (one), the Timer/Counter3 Capture Interrupt is executed.

## TIMER COUNTER 1

### TCCR1A - Timer/Counter1 Control Register A

`sfrb TCCR1A = $80;`

##### WGM10 - Waveform Generation Mode

`#define WGM10_BIT 0`

`#define WGM10_MASK 1`

Combined with the WGM13:2 bits found in the TCCR1B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### WGM11 - Waveform Generation Mode

`#define WGM11_BIT 1`

`#define WGM11_MASK 2`

Combined with the WGM13:2 bits found in the TCCR1B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### COM1C0 - Compare Output Mode 1C, bit 0

`#define COM1C0_BIT 2`

`#define COM1C0_MASK 4`

The COM1C1 and COM1C0 control bits determine any output pin action following a compare match in Timer/Counter1. Any output pin actions affect pin OC1B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM1C1 - Compare Output Mode 1C, bit 1

`#define COM1C1_BIT 3`

`#define COM1C1_MASK 8`

The COM1C1 and COM1C0 control bits determine any output pin action following a compare match in Timer/Counter1. Any output pin actions affect pin OC1B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM1B0 - Compare Output Mode 1B, bit 0

`#define COM1B0_BIT 4`

`#define COM1B0_MASK 16`

The COM1B1 and COM1B0 control bits determine any output pin action following a compare match in Timer/Counter1. Any output pin actions affect pin OC1B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM1B1 - Compare Output Mode 1B, bit 1

`#define COM1B1_BIT 5`

`#define COM1B1_MASK 32`

The COM1B1 and COM1B0 control bits determine any output pin action following a compare match in Timer/Counter1. Any output pin actions affect pin OC1B - Output CompareB. This is an alternative function to an I/O port, and the corre-sponding direction control bit must be set (one) to control an output pin.

##### COM1A0 - Compare Output Mode 1A, bit 0

`#define COM1A0_BIT 6`

`#define COM1A0_MASK 64`

The COM1A1 and COM1A0 control bits determine any output pin action following a compare match in Timer/Counter1. Any output pin actions affect pin OC1A - Output CompareA. This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. The control configuration is shown in Table 10.

##### COM1A1 - Compare Output Mode 1A, bit 1

`#define COM1A1_BIT 7`

`#define COM1A1_MASK 128`

The COM1A1 and COM1A0 control bits determine any output pin action following a compare match in Timer/Counter1. Any output pin actions affect pin OC1A - Output CompareA. This is an alternative function to an I/O port, and the corresponding direction control bit must be set (one) to control an output pin. The control configuration is shown in Table 10.

### TCCR1B - Timer/Counter1 Control Register B

`sfrb TCCR1B = $81;`

##### CS10 - Prescaler source of Timer/Counter 1

`#define CS10_BIT 0`

`#define CS10_MASK 1`

Select Prescaling Clock Source of Timer/Counter1. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T1, falling edge. (1:1:1) = External Pin 1, rising edge.

##### CS11 - Prescaler source of Timer/Counter 1

`#define CS11_BIT 1`

`#define CS11_MASK 2`

Select Prescaling Clock Source of Timer/Counter1. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T1, falling edge. (1:1:1) = External Pin 1, rising edge.

##### CS12 - Prescaler source of Timer/Counter 1

`#define CS12_BIT 2`

`#define CS12_MASK 4`

Select Prescaling Clock Source of Timer/Counter1. (0:0:0) = Stop. (0:0:1) = CK. (0:1:0) = CK / 8. (0:1:1) = CK / 64. (1:0:0) = CK / 256. (1:0:1) = CK / 1024. (1:1:0) = External Pin T1, falling edge. (1:1:1) = External Pin 1, rising edge.

##### WGM12 - Waveform Generation Mode

`#define WGM12_BIT 3`

`#define WGM12_MASK 8`

Combined with the WGM13:2 bits found in the TCCR1B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### WGM13 - Waveform Generation Mode

`#define WGM13_BIT 4`

`#define WGM13_MASK 16`

Combined with the WGM13:2 bits found in the TCCR1B register,these bits control the counting sequence of the counter, the source for maximum (TOP)counter value,and what type of waveform generation to be used.Modes of operation supported by the timer/counter unit are:Normal mode (counter),Clear Timer on Compare match (CTC)mode,and three types of Pulse Width Modulation (PWM)modes. PLease refer to the manual for a Mode Bit Description Table.

##### ICES1 - Input Capture 1 Edge Select

`#define ICES1_BIT 6`

`#define ICES1_MASK 64`

While the ICES1 bit is cleared (zero), the Timer/Counter1 contents are transferred to the Input Capture Register - ICR1 - on the falling edge of the input capture pin - ICP. While the ICES1 bit is set (one), the Timer/Counter1 contents are transferred to the Input Capture Register - ICR1 - on the rising edge of the input capture pin - ICP.

##### ICNC1 - Input Capture 1 Noise Canceler

`#define ICNC1_BIT 7`

`#define ICNC1_MASK 128`

When the ICNC1 bit is cleared (zero), the input capture trigger noise canceler function is disabled. The input capture is triggered at the first rising/falling edge sampled on the ICP - input capture pin - as specified. When the ICNC1 bit is set (one), four successive samples are measures on the ICP - input capture pin, and all samples must be high/low according to the input capture trigger specification in the ICES1 bit. The actual sampling frequency is XTAL clock frequency.

### TCCR1C - Timer/Counter 1 Control Register C

`sfrb TCCR1C = $82;`

##### FOC1C - Force Output Compare 1C

`#define FOC1C_BIT 5`

`#define FOC1C_MASK 32`

Writing a logical one to this bit, forces a change in the compare match output pin PD4 according to the values already set in COM1B1 and COM1B0.If the COM1B1 and COM1B0 bits are written in the same cycle as FOC1B,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM1B1 and COM1B0 happens as if a Compare Match had occurred, but no interrupt is generated. The corresponding I/O pin must be set as an output pin for the FOC1B bit to have effect on the pin. The FOC1B bit will always be read as zero. The setting of the FOC1B bit has no effect in PWM mo

##### FOC1B - Force Output Compare 1B

`#define FOC1B_BIT 6`

`#define FOC1B_MASK 64`

Writing a logical one to this bit, forces a change in the compare match output pin PD4 according to the values already set in COM1B1 and COM1B0.If the COM1B1 and COM1B0 bits are written in the same cycle as FOC1B,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM1B1 and COM1B0 happens as if a Compare Match had occurred, but no interrupt is generated. The corresponding I/O pin must be set as an output pin for the FOC1B bit to have effect on the pin. The FOC1B bit will always be read as zero. The setting of the FOC1B bit has no effect in PWM mo

##### FOC1A - Force Output Compare 1A

`#define FOC1A_BIT 7`

`#define FOC1A_MASK 128`

Writing a logical one to this bit, forces a change in the compare match output pin PD5 according to the values already set in COM1A1 and COM1A0.If the COM1A1 and COM1A0 bits are written in the same cycle as FOC1A,the new settings will not take effect until next compare match or forced compare match occurs. The Force Output Compare bit can be used to change the output pin without waiting for a compare match in the timer. The automatic action programmed in COM1A1 and COM1A0 happens as if a Compare Match had occurred, but no interrupt is generated and it will not clear the timer even if CTC1 in TCCR1B is set. The corresponding I/O pin must be set as an output pin for the FOC1A bit to have effect on the pin. The FOC1A bit will always be read as zero. The setting of the FOC1A bit has no effect in PWM m

### TCNT1H - Timer/Counter1 High Byte

`sfrb TCNT1H = $85;`

##### TCNT1H0 - Timer/Counter1 High Byte bit 0

`#define TCNT1H0_BIT 0`

`#define TCNT1H0_MASK 1`

##### TCNT1H1 - Timer/Counter1 High Byte bit 1

`#define TCNT1H1_BIT 1`

`#define TCNT1H1_MASK 2`

##### TCNT1H2 - Timer/Counter1 High Byte bit 2

`#define TCNT1H2_BIT 2`

`#define TCNT1H2_MASK 4`

##### TCNT1H3 - Timer/Counter1 High Byte bit 3

`#define TCNT1H3_BIT 3`

`#define TCNT1H3_MASK 8`

##### TCNT1H4 - Timer/Counter1 High Byte bit 4

`#define TCNT1H4_BIT 4`

`#define TCNT1H4_MASK 16`

##### TCNT1H5 - Timer/Counter1 High Byte bit 5

`#define TCNT1H5_BIT 5`

`#define TCNT1H5_MASK 32`

##### TCNT1H6 - Timer/Counter1 High Byte bit 6

`#define TCNT1H6_BIT 6`

`#define TCNT1H6_MASK 64`

##### TCNT1H7 - Timer/Counter1 High Byte bit 7

`#define TCNT1H7_BIT 7`

`#define TCNT1H7_MASK 128`

### TCNT1L - Timer/Counter1 Low Byte

`sfrb TCNT1L = $84;`

##### TCNT1L0 - Timer/Counter1 Low Byte bit 0

`#define TCNT1L0_BIT 0`

`#define TCNT1L0_MASK 1`

##### TCNT1L1 - Timer/Counter1 Low Byte bit 1

`#define TCNT1L1_BIT 1`

`#define TCNT1L1_MASK 2`

##### TCNT1L2 - Timer/Counter1 Low Byte bit 2

`#define TCNT1L2_BIT 2`

`#define TCNT1L2_MASK 4`

##### TCNT1L3 - Timer/Counter1 Low Byte bit 3

`#define TCNT1L3_BIT 3`

`#define TCNT1L3_MASK 8`

##### TCNT1L4 - Timer/Counter1 Low Byte bit 4

`#define TCNT1L4_BIT 4`

`#define TCNT1L4_MASK 16`

##### TCNT1L5 - Timer/Counter1 Low Byte bit 5

`#define TCNT1L5_BIT 5`

`#define TCNT1L5_MASK 32`

##### TCNT1L6 - Timer/Counter1 Low Byte bit 6

`#define TCNT1L6_BIT 6`

`#define TCNT1L6_MASK 64`

##### TCNT1L7 - Timer/Counter1 Low Byte bit 7

`#define TCNT1L7_BIT 7`

`#define TCNT1L7_MASK 128`

### OCR1AH - Timer/Counter1 Outbut Compare Register A High Byte

`sfrb OCR1AH = $89;`

##### OCR1AH0 - Timer/Counter1 Outbut Compare Register High Byte bit 0

`#define OCR1AH0_BIT 0`

`#define OCR1AH0_MASK 1`

##### OCR1AH1 - Timer/Counter1 Outbut Compare Register High Byte bit 1

`#define OCR1AH1_BIT 1`

`#define OCR1AH1_MASK 2`

##### OCR1AH2 - Timer/Counter1 Outbut Compare Register High Byte bit 2

`#define OCR1AH2_BIT 2`

`#define OCR1AH2_MASK 4`

##### OCR1AH3 - Timer/Counter1 Outbut Compare Register High Byte bit 3

`#define OCR1AH3_BIT 3`

`#define OCR1AH3_MASK 8`

##### OCR1AH4 - Timer/Counter1 Outbut Compare Register High Byte bit 4

`#define OCR1AH4_BIT 4`

`#define OCR1AH4_MASK 16`

##### OCR1AH5 - Timer/Counter1 Outbut Compare Register High Byte bit 5

`#define OCR1AH5_BIT 5`

`#define OCR1AH5_MASK 32`

##### OCR1AH6 - Timer/Counter1 Outbut Compare Register High Byte bit 6

`#define OCR1AH6_BIT 6`

`#define OCR1AH6_MASK 64`

##### OCR1AH7 - Timer/Counter1 Outbut Compare Register High Byte bit 7

`#define OCR1AH7_BIT 7`

`#define OCR1AH7_MASK 128`

### OCR1AL - Timer/Counter1 Outbut Compare Register A Low Byte

`sfrb OCR1AL = $88;`

##### OCR1AL0 - Timer/Counter1 Outbut Compare Register Low Byte Bit 0

`#define OCR1AL0_BIT 0`

`#define OCR1AL0_MASK 1`

##### OCR1AL1 - Timer/Counter1 Outbut Compare Register Low Byte Bit 1

`#define OCR1AL1_BIT 1`

`#define OCR1AL1_MASK 2`

##### OCR1AL2 - Timer/Counter1 Outbut Compare Register Low Byte Bit 2

`#define OCR1AL2_BIT 2`

`#define OCR1AL2_MASK 4`

##### OCR1AL3 - Timer/Counter1 Outbut Compare Register Low Byte Bit 3

`#define OCR1AL3_BIT 3`

`#define OCR1AL3_MASK 8`

##### OCR1AL4 - Timer/Counter1 Outbut Compare Register Low Byte Bit 4

`#define OCR1AL4_BIT 4`

`#define OCR1AL4_MASK 16`

##### OCR1AL5 - Timer/Counter1 Outbut Compare Register Low Byte Bit 5

`#define OCR1AL5_BIT 5`

`#define OCR1AL5_MASK 32`

##### OCR1AL6 - Timer/Counter1 Outbut Compare Register Low Byte Bit 6

`#define OCR1AL6_BIT 6`

`#define OCR1AL6_MASK 64`

##### OCR1AL7 - Timer/Counter1 Outbut Compare Register Low Byte Bit 7

`#define OCR1AL7_BIT 7`

`#define OCR1AL7_MASK 128`

### OCR1BH - Timer/Counter1 Output Compare Register B High Byte

`sfrb OCR1BH = $8B;`

##### OCR1BH0 - Timer/Counter1 Output Compare Register High Byte bit 0

`#define OCR1BH0_BIT 0`

`#define OCR1BH0_MASK 1`

##### OCR1BH1 - Timer/Counter1 Output Compare Register High Byte bit 1

`#define OCR1BH1_BIT 1`

`#define OCR1BH1_MASK 2`

##### OCR1BH2 - Timer/Counter1 Output Compare Register High Byte bit 2

`#define OCR1BH2_BIT 2`

`#define OCR1BH2_MASK 4`

##### OCR1BH3 - Timer/Counter1 Output Compare Register High Byte bit 3

`#define OCR1BH3_BIT 3`

`#define OCR1BH3_MASK 8`

##### OCR1BH4 - Timer/Counter1 Output Compare Register High Byte bit 4

`#define OCR1BH4_BIT 4`

`#define OCR1BH4_MASK 16`

##### OCR1BH5 - Timer/Counter1 Output Compare Register High Byte bit 5

`#define OCR1BH5_BIT 5`

`#define OCR1BH5_MASK 32`

##### OCR1BH6 - Timer/Counter1 Output Compare Register High Byte bit 6

`#define OCR1BH6_BIT 6`

`#define OCR1BH6_MASK 64`

##### OCR1BH7 - Timer/Counter1 Output Compare Register High Byte bit 7

`#define OCR1BH7_BIT 7`

`#define OCR1BH7_MASK 128`

### OCR1BL - Timer/Counter1 Output Compare Register B Low Byte

`sfrb OCR1BL = $8A;`

##### OCR1BL0 - Timer/Counter1 Output Compare Register Low Byte bit 0

`#define OCR1BL0_BIT 0`

`#define OCR1BL0_MASK 1`

##### OCR1BL1 - Timer/Counter1 Output Compare Register Low Byte bit 1

`#define OCR1BL1_BIT 1`

`#define OCR1BL1_MASK 2`

##### OCR1BL2 - Timer/Counter1 Output Compare Register Low Byte bit 2

`#define OCR1BL2_BIT 2`

`#define OCR1BL2_MASK 4`

##### OCR1BL3 - Timer/Counter1 Output Compare Register Low Byte bit 3

`#define OCR1BL3_BIT 3`

`#define OCR1BL3_MASK 8`

##### OCR1BL4 - Timer/Counter1 Output Compare Register Low Byte bit 4

`#define OCR1BL4_BIT 4`

`#define OCR1BL4_MASK 16`

##### OCR1BL5 - Timer/Counter1 Output Compare Register Low Byte bit 5

`#define OCR1BL5_BIT 5`

`#define OCR1BL5_MASK 32`

##### OCR1BL6 - Timer/Counter1 Output Compare Register Low Byte bit 6

`#define OCR1BL6_BIT 6`

`#define OCR1BL6_MASK 64`

##### OCR1BL7 - Timer/Counter1 Output Compare Register Low Byte bit 7

`#define OCR1BL7_BIT 7`

`#define OCR1BL7_MASK 128`

### OCR1CH - Timer/Counter1 Output Compare Register B High Byte

`sfrb OCR1CH = $8D;`

##### OCR1CH0 - Timer/Counter1 Output Compare Register High Byte bit 0

`#define OCR1CH0_BIT 0`

`#define OCR1CH0_MASK 1`

##### OCR1CH1 - Timer/Counter1 Output Compare Register High Byte bit 1

`#define OCR1CH1_BIT 1`

`#define OCR1CH1_MASK 2`

##### OCR1CH2 - Timer/Counter1 Output Compare Register High Byte bit 2

`#define OCR1CH2_BIT 2`

`#define OCR1CH2_MASK 4`

##### OCR1CH3 - Timer/Counter1 Output Compare Register High Byte bit 3

`#define OCR1CH3_BIT 3`

`#define OCR1CH3_MASK 8`

##### OCR1CH4 - Timer/Counter1 Output Compare Register High Byte bit 4

`#define OCR1CH4_BIT 4`

`#define OCR1CH4_MASK 16`

##### OCR1CH5 - Timer/Counter1 Output Compare Register High Byte bit 5

`#define OCR1CH5_BIT 5`

`#define OCR1CH5_MASK 32`

##### OCR1CH6 - Timer/Counter1 Output Compare Register High Byte bit 6

`#define OCR1CH6_BIT 6`

`#define OCR1CH6_MASK 64`

##### OCR1CH7 - Timer/Counter1 Output Compare Register High Byte bit 7

`#define OCR1CH7_BIT 7`

`#define OCR1CH7_MASK 128`

### OCR1CL - Timer/Counter1 Output Compare Register B Low Byte

`sfrb OCR1CL = $8C;`

##### OCR1CL0 - Timer/Counter1 Output Compare Register Low Byte bit 0

`#define OCR1CL0_BIT 0`

`#define OCR1CL0_MASK 1`

##### OCR1CL1 - Timer/Counter1 Output Compare Register Low Byte bit 1

`#define OCR1CL1_BIT 1`

`#define OCR1CL1_MASK 2`

##### OCR1CL2 - Timer/Counter1 Output Compare Register Low Byte bit 2

`#define OCR1CL2_BIT 2`

`#define OCR1CL2_MASK 4`

##### OCR1CL3 - Timer/Counter1 Output Compare Register Low Byte bit 3

`#define OCR1CL3_BIT 3`

`#define OCR1CL3_MASK 8`

##### OCR1CL4 - Timer/Counter1 Output Compare Register Low Byte bit 4

`#define OCR1CL4_BIT 4`

`#define OCR1CL4_MASK 16`

##### OCR1CL5 - Timer/Counter1 Output Compare Register Low Byte bit 5

`#define OCR1CL5_BIT 5`

`#define OCR1CL5_MASK 32`

##### OCR1CL6 - Timer/Counter1 Output Compare Register Low Byte bit 6

`#define OCR1CL6_BIT 6`

`#define OCR1CL6_MASK 64`

##### OCR1CL7 - Timer/Counter1 Output Compare Register Low Byte bit 7

`#define OCR1CL7_BIT 7`

`#define OCR1CL7_MASK 128`

### ICR1H - Timer/Counter1 Input Capture Register High Byte

`sfrb ICR1H = $87;`

##### ICR1H0 - Timer/Counter1 Input Capture Register High Byte bit 0

`#define ICR1H0_BIT 0`

`#define ICR1H0_MASK 1`

##### ICR1H1 - Timer/Counter1 Input Capture Register High Byte bit 1

`#define ICR1H1_BIT 1`

`#define ICR1H1_MASK 2`

##### ICR1H2 - Timer/Counter1 Input Capture Register High Byte bit 2

`#define ICR1H2_BIT 2`

`#define ICR1H2_MASK 4`

##### ICR1H3 - Timer/Counter1 Input Capture Register High Byte bit 3

`#define ICR1H3_BIT 3`

`#define ICR1H3_MASK 8`

##### ICR1H4 - Timer/Counter1 Input Capture Register High Byte bit 4

`#define ICR1H4_BIT 4`

`#define ICR1H4_MASK 16`

##### ICR1H5 - Timer/Counter1 Input Capture Register High Byte bit 5

`#define ICR1H5_BIT 5`

`#define ICR1H5_MASK 32`

##### ICR1H6 - Timer/Counter1 Input Capture Register High Byte bit 6

`#define ICR1H6_BIT 6`

`#define ICR1H6_MASK 64`

##### ICR1H7 - Timer/Counter1 Input Capture Register High Byte bit 7

`#define ICR1H7_BIT 7`

`#define ICR1H7_MASK 128`

### ICR1L - Timer/Counter1 Input Capture Register Low Byte

`sfrb ICR1L = $86;`

##### ICR1L0 - Timer/Counter1 Input Capture Register Low Byte bit 0

`#define ICR1L0_BIT 0`

`#define ICR1L0_MASK 1`

##### ICR1L1 - Timer/Counter1 Input Capture Register Low Byte bit 1

`#define ICR1L1_BIT 1`

`#define ICR1L1_MASK 2`

##### ICR1L2 - Timer/Counter1 Input Capture Register Low Byte bit 2

`#define ICR1L2_BIT 2`

`#define ICR1L2_MASK 4`

##### ICR1L3 - Timer/Counter1 Input Capture Register Low Byte bit 3

`#define ICR1L3_BIT 3`

`#define ICR1L3_MASK 8`

##### ICR1L4 - Timer/Counter1 Input Capture Register Low Byte bit 4

`#define ICR1L4_BIT 4`

`#define ICR1L4_MASK 16`

##### ICR1L5 - Timer/Counter1 Input Capture Register Low Byte bit 5

`#define ICR1L5_BIT 5`

`#define ICR1L5_MASK 32`

##### ICR1L6 - Timer/Counter1 Input Capture Register Low Byte bit 6

`#define ICR1L6_BIT 6`

`#define ICR1L6_MASK 64`

##### ICR1L7 - Timer/Counter1 Input Capture Register Low Byte bit 7

`#define ICR1L7_BIT 7`

`#define ICR1L7_MASK 128`

### TIMSK1 - Timer/Counter1 Interrupt Mask Register

`sfrb TIMSK1 = $6F;`

##### TOIE1 - Timer/Counter1 Overflow Interrupt Enable

`#define TOIE1_BIT 0`

`#define TOIE1_MASK 1`

When the TOIE1 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Overflow interrupt is enabled. The corresponding interrupt (at vector $006) is executed if an overflow in Timer/Counter1 occurs, i.e., when the TOV1 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE1A - Timer/Counter1 Output Compare A Match Interrupt Enable

`#define OCIE1A_BIT 1`

`#define OCIE1A_MASK 2`

When the OCIE1A bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 CompareA Match interrupt is enabled. The corresponding interrupt (at vector $004) is executed if a CompareA match in Timer/Counter1 occurs, i.e., when the OCF1A bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE1B - Timer/Counter1 Output Compare B Match Interrupt Enable

`#define OCIE1B_BIT 2`

`#define OCIE1B_MASK 4`

When the OCIE1B bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 CompareB Match interrupt is enabled. The corresponding interrupt (at vector $005) is executed if a CompareB match in Timer/Counter1 occurs, i.e., when the OCF1B bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### OCIE1C - Timer/Counter1 Output Compare C Match Interrupt Enable

`#define OCIE1C_BIT 3`

`#define OCIE1C_MASK 8`

When the OCIE1C bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 CompareB Match interrupt is enabled. The corresponding interrupt (at vector $005) is executed if a CompareB match in Timer/Counter1 occurs, i.e., when the OCF1B bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

##### ICIE1 - Timer/Counter1 Input Capture Interrupt Enable

`#define ICIE1_BIT 5`

`#define ICIE1_MASK 32`

When the TICIE1 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter1 Input Capture Event Interrupt is enabled. The corresponding interrupt (at vector $003) is executed if a capture-triggering event occurs on pin 31, ICP, i.e., when the ICF1 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

### TIFR1 - Timer/Counter1 Interrupt Flag register

`sfrb TIFR1 = $16;`

##### TOV1 - Timer/Counter1 Overflow Flag

`#define TOV1_BIT 0`

`#define TOV1_MASK 1`

The TOV1 is set (one) when an overflow occurs in Timer/Counter1. TOV1 is cleared by hardware when executing the cor-responding interrupt handling vector. Alternatively, TOV1 is cleared by writing a logic one to the flag. When the I-bit in SREG, and TOIE1 (Timer/Counter1 Overflow Interrupt Enable), and TOV1 are set (one), the Timer/Counter1 Overflow Interrupt is executed. In PWM mode, this bit is set when Timer/Counter1 changes counting direction at $0000.

##### OCF1A - Output Compare Flag 1A

`#define OCF1A_BIT 1`

`#define OCF1A_MASK 2`

The OCF1A bit is set (one) when compare match occurs between the Timer/Counter1 and the data in OCR1A - Output Compare Register 1A. OCF1A is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF1A is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE1A (Timer/Counter1 Compare match InterruptA Enable), and the OCF1A are set (one), the Timer/Counter1 Compare A match Interrupt is executed.

##### OCF1B - Output Compare Flag 1B

`#define OCF1B_BIT 2`

`#define OCF1B_MASK 4`

The OCF1B bit is set (one) when compare match occurs between the Timer/Counter1 and the data in OCR1B - Output Compare Register 1B. OCF1B is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF1B is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE1B (Timer/Counter1 Compare match InterruptB Enable), and the OCF1B are set (one), the Timer/Counter1 Compare B match Interrupt is executed.

##### OCF1C - Output Compare Flag 1C

`#define OCF1C_BIT 3`

`#define OCF1C_MASK 8`

The OCF1C bit is set (one) when compare match occurs between the Timer/Counter1 and the data in OCR1B - Output Compare Register 1B. OCF1B is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF1B is cleared by writing a logic one to the flag. When the I-bit in SREG, and OCIE1B (Timer/Counter1 Compare match InterruptB Enable), and the OCF1B are set (one), the Timer/Counter1 Compare B match Interrupt is executed.

##### ICF1 - Input Capture Flag 1

`#define ICF1_BIT 5`

`#define ICF1_MASK 32`

The ICF1 bit is set (one) to flag an input capture event, indicating that the Timer/Counter1 value has been transferred to the input capture register - ICR1. ICF1 is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, ICF1 is cleared by writing a logic one to the flag. When the SREG I-bit, and TICIE1 (Timer/Counter1 Input Capture Interrupt Enable), and ICF1 are set (one), the Timer/Counter1 Capture Interrupt is executed.

## JTAG

JTAG Features: JTAG (IEEE std. 1149.1 compliant) Interface. Boundary-Scan Capabilities According to the IEEE std. 1149.1 (JTAG) Standard. Debugger Access to: ? All Internal Peripheral Units ? Internal and External RAM ? The Internal Register File ?Program Counter ? EEPROM and Flash Memories. Extensive On-Chip Debug Support for Break Conditions, Including: ?AVR Break Instruction ? Break on Change of Program Memory Flow ?Single Step Break ?Program Memory Breakpoints on Single Address or Address Range ? Data Memory Breakpoints on Single Address or Address Range. Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG Interface. On-Chip Debugging Supported by AVR Stu

### OCDR - On-Chip Debug Related Register in I/O Memory

`sfrb OCDR = $31;`

##### OCDR0 - On-Chip Debug Register Bit 0

`#define OCDR0_BIT 0`

`#define OCDR0_MASK 1`

##### OCDR1 - On-Chip Debug Register Bit 1

`#define OCDR1_BIT 1`

`#define OCDR1_MASK 2`

##### OCDR2 - On-Chip Debug Register Bit 2

`#define OCDR2_BIT 2`

`#define OCDR2_MASK 4`

##### OCDR3 - On-Chip Debug Register Bit 3

`#define OCDR3_BIT 3`

`#define OCDR3_MASK 8`

##### OCDR4 - On-Chip Debug Register Bit 4

`#define OCDR4_BIT 4`

`#define OCDR4_MASK 16`

##### OCDR5 - On-Chip Debug Register Bit 5

`#define OCDR5_BIT 5`

`#define OCDR5_MASK 32`

##### OCDR6 - On-Chip Debug Register Bit 6

`#define OCDR6_BIT 6`

`#define OCDR6_MASK 64`

##### OCDR7 - On-Chip Debug Register Bit 7

`#define OCDR7_BIT 7`

`#define OCDR7_MASK 128`

### MCUCR - MCU Control Register

`sfrb MCUCR = $35;`

##### JTD - JTAG Interface Disable

`#define JTD_BIT 7`

`#define JTD_MASK 128`

When this bit is written to zero, the JTAG interface is enabled if the JTAGEN fuse is programmed. If this bit is written to one, the JTAG interface is disabled. In order to avoid unintentional disabling or enabling of the JTAG interface, a timed sequence must be followed: The application software must write this to the desired value twice within four cycles to change the bit.

### MCUSR - MCU Status Register

`sfrb MCUSR = $34;`

##### JTRF - JTAG Reset Flag

`#define JTRF_BIT 4`

`#define JTRF_MASK 16`

This bit is set if a reset is being caused by a logic one in the JTAG Reset Register selected by the JTAG instruction AVR_RESET.This bit is reset by a Power-on reset,or by writing a logic zero to the flag.

## EXTERNAL INTERRUPT

The external interrupts are triggered by the INT7:0 pins. Observe that, if enabled, the interrupts will trigger even if the INT7:0 pins are configured as outputs. This feature provides a way of generating a software interrupt. The external inter-rupts can be triggered by a falling or rising edge or a low level. This is set up as indicated in the specification for the Exter-nal Interrupt Control Registers - EICRA (INT3:0) and EICRB (INT7:4). When the external interrupt is enabled and is configured as level triggered, the interrupt will trigger as long as the pin is held low. Note that recognition of falling or rising edge interrupts on INT7:4 requires the presence of an I/O clock, described in ?Clock Systems and their Distribution? on page 29. Low level interrupts and the edge interrupt on INT3:0 are detected asynchronously. This implies that these inter-rupts can be used for waking the part also from sleep modes other than Idle mode. The I/O clock is halted in all sleep modes except Idle mode. Note that if a level triggered interrupt is used for wake-up from Power Down Mode, the changed level must be held for some time to wake up the MCU. This makes the MCU less sensitive to noise. The changed level is sampled twice by the watchdog oscillator clock. The period of the watchdog oscillator is 1 µs (nominal) at 5.0V and 25°C. The frequency of the watchdog oscillator is voltage dependent as shown in the Electrical Characteristics section. The MCU will wake up if the input has the required level during this sampling or if it is held until the end of the start-up time. The start-up time is defined by the SUT fuses as described in ?Clock Systems and their Distribution? on page 29. If the level is sampled twice by the watchdog oscillator clock but disappears before the end of the start-up time, the MCU will still wake up, but no interrupt will be generated. The required level must be held long enough for the MCU to complete the wake up to trigger the level interrupt

### EICRA - External Interrupt Control Register A

`sfrb EICRA = $69;`

##### ISC00 - External Interrupt Sense Control Bit

`#define ISC00_BIT 0`

`#define ISC00_MASK 1`

##### ISC01 - External Interrupt Sense Control Bit

`#define ISC01_BIT 1`

`#define ISC01_MASK 2`

##### ISC10 - External Interrupt Sense Control Bit

`#define ISC10_BIT 2`

`#define ISC10_MASK 4`

##### ISC11 - External Interrupt Sense Control Bit

`#define ISC11_BIT 3`

`#define ISC11_MASK 8`

##### ISC20 - External Interrupt Sense Control Bit

`#define ISC20_BIT 4`

`#define ISC20_MASK 16`

##### ISC21 - External Interrupt Sense Control Bit

`#define ISC21_BIT 5`

`#define ISC21_MASK 32`

##### ISC30 - External Interrupt Sense Control Bit

`#define ISC30_BIT 6`

`#define ISC30_MASK 64`

##### ISC31 - External Interrupt Sense Control Bit

`#define ISC31_BIT 7`

`#define ISC31_MASK 128`

### EICRB - External Interrupt Control Register B

`sfrb EICRB = $6A;`

##### ISC40 - External Interrupt 7-4 Sense Control Bit

`#define ISC40_BIT 0`

`#define ISC40_MASK 1`

##### ISC41 - External Interrupt 7-4 Sense Control Bit

`#define ISC41_BIT 1`

`#define ISC41_MASK 2`

##### ISC50 - External Interrupt 7-4 Sense Control Bit

`#define ISC50_BIT 2`

`#define ISC50_MASK 4`

##### ISC51 - External Interrupt 7-4 Sense Control Bit

`#define ISC51_BIT 3`

`#define ISC51_MASK 8`

##### ISC60 - External Interrupt 7-4 Sense Control Bit

`#define ISC60_BIT 4`

`#define ISC60_MASK 16`

##### ISC61 - External Interrupt 7-4 Sense Control Bit

`#define ISC61_BIT 5`

`#define ISC61_MASK 32`

##### ISC70 - External Interrupt 7-4 Sense Control Bit

`#define ISC70_BIT 6`

`#define ISC70_MASK 64`

##### ISC71 - External Interrupt 7-4 Sense Control Bit

`#define ISC71_BIT 7`

`#define ISC71_MASK 128`

### EIMSK - External Interrupt Mask Register

`sfrb EIMSK = $1D;`

##### INT0 - External Interrupt Request 0 Enable

`#define INT0_BIT 0`

`#define INT0_MASK 1`

##### INT1 - External Interrupt Request 1 Enable

`#define INT1_BIT 1`

`#define INT1_MASK 2`

##### INT2 - External Interrupt Request 2 Enable

`#define INT2_BIT 2`

`#define INT2_MASK 4`

##### INT3 - External Interrupt Request 3 Enable

`#define INT3_BIT 3`

`#define INT3_MASK 8`

##### INT4 - External Interrupt Request 4 Enable

`#define INT4_BIT 4`

`#define INT4_MASK 16`

##### INT5 - External Interrupt Request 5 Enable

`#define INT5_BIT 5`

`#define INT5_MASK 32`

##### INT6 - External Interrupt Request 6 Enable

`#define INT6_BIT 6`

`#define INT6_MASK 64`

##### INT7 - External Interrupt Request 7 Enable

`#define INT7_BIT 7`

`#define INT7_MASK 128`

### EIFR - External Interrupt Flag Register

`sfrb EIFR = $1C;`

##### INTF0 - External Interrupt Flag 0

`#define INTF0_BIT 0`

`#define INTF0_MASK 1`

##### INTF1 - External Interrupt Flag 1

`#define INTF1_BIT 1`

`#define INTF1_MASK 2`

##### INTF2 - External Interrupt Flag 2

`#define INTF2_BIT 2`

`#define INTF2_MASK 4`

##### INTF3 - External Interrupt Flag 3

`#define INTF3_BIT 3`

`#define INTF3_MASK 8`

##### INTF4 - External Interrupt Flag 4

`#define INTF4_BIT 4`

`#define INTF4_MASK 16`

##### INTF5 - External Interrupt Flag 5

`#define INTF5_BIT 5`

`#define INTF5_MASK 32`

##### INTF6 - External Interrupt Flag 6

`#define INTF6_BIT 6`

`#define INTF6_MASK 64`

##### INTF7 - External Interrupt Flag 7

`#define INTF7_BIT 7`

`#define INTF7_MASK 128`

### PCMSK2 - Pin Change Mask Register 2

`sfrb PCMSK2 = $6D;`

##### PCINT16 - Pin Change Enable Mask 16

`#define PCINT16_BIT 0`

`#define PCINT16_MASK 1`

##### PCINT17 - Pin Change Enable Mask 17

`#define PCINT17_BIT 1`

`#define PCINT17_MASK 2`

##### PCINT18 - Pin Change Enable Mask 18

`#define PCINT18_BIT 2`

`#define PCINT18_MASK 4`

##### PCINT19 - Pin Change Enable Mask 19

`#define PCINT19_BIT 3`

`#define PCINT19_MASK 8`

##### PCINT20 - Pin Change Enable Mask 20

`#define PCINT20_BIT 4`

`#define PCINT20_MASK 16`

##### PCINT21 - Pin Change Enable Mask 21

`#define PCINT21_BIT 5`

`#define PCINT21_MASK 32`

##### PCINT22 - Pin Change Enable Mask 22

`#define PCINT22_BIT 6`

`#define PCINT22_MASK 64`

##### PCINT23 - Pin Change Enable Mask 23

`#define PCINT23_BIT 7`

`#define PCINT23_MASK 128`

### PCMSK1 - Pin Change Mask Register 1

`sfrb PCMSK1 = $6C;`

##### PCINT8 - Pin Change Enable Mask 8

`#define PCINT8_BIT 0`

`#define PCINT8_MASK 1`

##### PCINT9 - Pin Change Enable Mask 9

`#define PCINT9_BIT 1`

`#define PCINT9_MASK 2`

##### PCINT10 - Pin Change Enable Mask 10

`#define PCINT10_BIT 2`

`#define PCINT10_MASK 4`

##### PCINT11 - Pin Change Enable Mask 11

`#define PCINT11_BIT 3`

`#define PCINT11_MASK 8`

##### PCINT12 - Pin Change Enable Mask 12

`#define PCINT12_BIT 4`

`#define PCINT12_MASK 16`

##### PCINT13 - Pin Change Enable Mask 13

`#define PCINT13_BIT 5`

`#define PCINT13_MASK 32`

##### PCINT14 - Pin Change Enable Mask 14

`#define PCINT14_BIT 6`

`#define PCINT14_MASK 64`

##### PCINT15 - Pin Change Enable Mask 15

`#define PCINT15_BIT 7`

`#define PCINT15_MASK 128`

### PCMSK0 - Pin Change Mask Register 0

`sfrb PCMSK0 = 0x6B;`

##### PCINT0 - Pin Change Enable Mask 0

`#define PCINT0_BIT 0`

`#define PCINT0_MASK 1`

##### PCINT1 - Pin Change Enable Mask 1

`#define PCINT1_BIT 1`

`#define PCINT1_MASK 2`

##### PCINT2 - Pin Change Enable Mask 2

`#define PCINT2_BIT 2`

`#define PCINT2_MASK 4`

##### PCINT3 - Pin Change Enable Mask 3

`#define PCINT3_BIT 3`

`#define PCINT3_MASK 8`

##### PCINT4 - Pin Change Enable Mask 4

`#define PCINT4_BIT 4`

`#define PCINT4_MASK 16`

##### PCINT5 - Pin Change Enable Mask 5

`#define PCINT5_BIT 5`

`#define PCINT5_MASK 32`

##### PCINT6 - Pin Change Enable Mask 6

`#define PCINT6_BIT 6`

`#define PCINT6_MASK 64`

##### PCINT7 - Pin Change Enable Mask 7

`#define PCINT7_BIT 7`

`#define PCINT7_MASK 128`

### PCIFR - Pin Change Interrupt Flag Register

`sfrb PCIFR = $1B;`

##### PCIF0 - Pin Change Interrupt Flag 0

`#define PCIF0_BIT 0`

`#define PCIF0_MASK 1`

When a logic change on any PCINT7..0 pin triggers an interrupt request, PCIF0 becomes set (one). If the I-bit in SREG and the PCIE0 bit in PCICR are set (one), the MCU will jump to the corresponding Interrupt Vector. The flag is cleared when the interrupt routine is executed. Alternatively, the flag can be cleared by writing a logical one to it.

##### PCIF1 - Pin Change Interrupt Flag 1

`#define PCIF1_BIT 1`

`#define PCIF1_MASK 2`

When a logic change on any PCINT14..8 pin triggers an interrupt request, PCIF1 becomes set (one). If the I-bit in SREG and the PCIE1 bit in PCICR are set (one), the MCU will jump to the corresponding Interrupt Vector. The flag is cleared when the interrupt routine is executed. Alternatively, the flag can be cleared by writing a logical one to it.

##### PCIF2 - Pin Change Interrupt Flag 2

`#define PCIF2_BIT 2`

`#define PCIF2_MASK 4`

When a logic change on any PCINT23..16 pin triggers an interrupt request, PCIF2 becomes set (one). If the I-bit in SREG and the PCIE2 bit in PCICR are set (one), the MCU will jump to the corresponding Interrupt Vector. The flag is cleared when the interrupt routine is executed. Alternatively, the flag can be cleared by writing a logical one to it.

### PCICR - Pin Change Interrupt Control Register

`sfrb PCICR = $68;`

##### PCIE0 - Pin Change Interrupt Enable 0

`#define PCIE0_BIT 0`

`#define PCIE0_MASK 1`

##### PCIE1 - Pin Change Interrupt Enable 1

`#define PCIE1_BIT 1`

`#define PCIE1_MASK 2`

##### PCIE2 - Pin Change Interrupt Enable 2

`#define PCIE2_BIT 2`

`#define PCIE2_MASK 4`

## CPU

### SREG - Status Register

`sfrb SREG = $3F;`

### SPH - Stack Pointer High

`sfrb SPH = $3E;`

##### SP8 - Stack pointer bit 8

`#define SP8_BIT 0`

`#define SP8_MASK 1`

##### SP9 - Stack pointer bit 9

`#define SP9_BIT 1`

`#define SP9_MASK 2`

##### SP10 - Stack pointer bit 10

`#define SP10_BIT 2`

`#define SP10_MASK 4`

##### SP11 - Stack pointer bit 11

`#define SP11_BIT 3`

`#define SP11_MASK 8`

##### SP12

`#define SP12_BIT 4`

`#define SP12_MASK 16`

##### SP13 - Stack pointer bit 13

`#define SP13_BIT 5`

`#define SP13_MASK 32`

##### SP14 - Stack pointer bit 14

`#define SP14_BIT 6`

`#define SP14_MASK 64`

##### SP15 - Stack pointer bit 15

`#define SP15_BIT 7`

`#define SP15_MASK 128`

### SPL - Stack Pointer Low

`sfrb SPL = $3D;`

##### SP0 - Stack pointer bit 0

`#define SP0_BIT 0`

`#define SP0_MASK 1`

##### SP1 - Stack pointer bit 1

`#define SP1_BIT 1`

`#define SP1_MASK 2`

##### SP2 - Stack pointer bit 2

`#define SP2_BIT 2`

`#define SP2_MASK 4`

##### SP3 - Stack pointer bit 3

`#define SP3_BIT 3`

`#define SP3_MASK 8`

##### SP4

`#define SP4_BIT 4`

`#define SP4_MASK 16`

##### SP5 - Stack pointer bit 5

`#define SP5_BIT 5`

`#define SP5_MASK 32`

##### SP6 - Stack pointer bit 6

`#define SP6_BIT 6`

`#define SP6_MASK 64`

##### SP7 - Stack pointer bit 7

`#define SP7_BIT 7`

`#define SP7_MASK 128`

### MCUCR - MCU Control Register

`sfrb MCUCR = $35;`

##### IVCE - Interrupt Vector Change Enable

`#define IVCE_BIT 0`

`#define IVCE_MASK 1`

The IVCE bit must be written to logic one to enable change of the IVSEL bit.IVCE is cleared by hardware four cycles after it is written or when IVSEL is written.Setting the IVCE bit will disable interrupts.

##### IVSEL - Interrupt Vector Select

`#define IVSEL_BIT 1`

`#define IVSEL_MASK 2`

When the IVSEL bit is cleared (zero),the interrupt vectors are placed at the start of the Flash memory.When this bit is set (one),the interrupt vectors are moved to the beginning of the Boot Loader section of the flash.The actual address of the start of the boot flash section is determined by the BOOTSZ fuses.

##### PUD - Pull-up disable

`#define PUD_BIT 4`

`#define PUD_MASK 16`

When this bit is written to one,the pull-ups in the I/O ports are disabled even if the DDxn and PORTxn registers are configured to enable the pull-ups ({DDxn,PORTxn}=0b01).

##### JTD - JTAG Interface Disable

`#define JTD_BIT 7`

`#define JTD_MASK 128`

When this bit is zero, the JTAG interface is enabled if the JTAGEN Fuse is programmed.

### MCUSR - MCU Status Register

`sfrb MCUSR = $34;`

##### PORF - Power-on reset flag

`#define PORF_BIT 0`

`#define PORF_MASK 1`

This bit is set if a power-on reset occurs. The bit is reset only by writing a logic zero to the flag. To make use of the reset flags to identify a reset condition, the user should read and then reset the MCUCSR as early as possible in the program. If the register is cleared before another reset occurs, the source of the reset can be found by examining the reset flags.

##### EXTRF - External Reset Flag

`#define EXTRF_BIT 1`

`#define EXTRF_MASK 2`

This bit is set if an external reset occurs. The bit is reset by a power-on reset, or by writing a logic zero to the flag.

##### BORF - Brown-out Reset Flag

`#define BORF_BIT 2`

`#define BORF_MASK 4`

This bit is set if a brown-out reset occurs. The bit is reset by a power-on reset, or by writing a logic zero to the flag.

##### WDRF - Watchdog Reset Flag

`#define WDRF_BIT 3`

`#define WDRF_MASK 8`

This bit is set if a watchdog reset occurs. The bit is reset by a power-on reset, or by writing a logic zero to the flag.

##### JTRF - JTAG Reset Flag

`#define JTRF_BIT 4`

`#define JTRF_MASK 16`

This bit is set if a reset is being caused by a logic one in the JTAG Reset Register selected by the JTAG instruction AVR_RESET. This bit is reset by a Power-on reset, or by writing a logic zero to the flag. ? Bit 3 - WDRF: Watchdog Reset Flag

### XMCRA - External Memory Control Register A

`sfrb XMCRA = $74;`

##### SRW00 - Wait state select bit lower page

`#define SRW00_BIT 0`

`#define SRW00_MASK 1`

##### SRW01 - Wait state select bit lower page

`#define SRW01_BIT 1`

`#define SRW01_MASK 2`

##### SRW10 - Wait state select bit upper page

`#define SRW10_BIT 2`

`#define SRW10_MASK 4`

##### SRW11 - Wait state select bit upper page

`#define SRW11_BIT 3`

`#define SRW11_MASK 8`

##### SRL0 - Wait state page limit

`#define SRL0_BIT 4`

`#define SRL0_MASK 16`

It is possible to configure different wait-states for different external memory addresses.

##### SRL1 - Wait state page limit

`#define SRL1_BIT 5`

`#define SRL1_MASK 32`

It is possible to configure different wait-states for different external memory addresses.

##### SRL2 - Wait state page limit

`#define SRL2_BIT 6`

`#define SRL2_MASK 64`

It is possible to configure different wait-states for different external memory addresses.

##### SRE - External SRAM Enable

`#define SRE_BIT 7`

`#define SRE_MASK 128`

Writing SRE to one enables the External Memory Interface.

### XMCRB - External Memory Control Register B

`sfrb XMCRB = $75;`

##### XMM0 - External Memory High Mask

`#define XMM0_BIT 0`

`#define XMM0_MASK 1`

Port C pins released.

##### XMM1 - External Memory High Mask

`#define XMM1_BIT 1`

`#define XMM1_MASK 2`

Port C pins released.

##### XMM2 - External Memory High Mask

`#define XMM2_BIT 2`

`#define XMM2_MASK 4`

Port C pins released.

##### XMBK - External Memory Bus Keeper Enable

`#define XMBK_BIT 7`

`#define XMBK_MASK 128`

Port C pins release command.

### OSCCAL - Oscillator Calibration Value

`sfrb OSCCAL = $66;`

##### CAL0 - Oscillator Calibration Value Bit0

`#define CAL0_BIT 0`

`#define CAL0_MASK 1`

##### CAL1 - Oscillator Calibration Value Bit1

`#define CAL1_BIT 1`

`#define CAL1_MASK 2`

##### CAL2 - Oscillator Calibration Value Bit2

`#define CAL2_BIT 2`

`#define CAL2_MASK 4`

##### CAL3 - Oscillator Calibration Value Bit3

`#define CAL3_BIT 3`

`#define CAL3_MASK 8`

##### CAL4 - Oscillator Calibration Value Bit4

`#define CAL4_BIT 4`

`#define CAL4_MASK 16`

##### CAL5 - Oscillator Calibration Value Bit5

`#define CAL5_BIT 5`

`#define CAL5_MASK 32`

##### CAL6 - Oscillator Calibration Value Bit6

`#define CAL6_BIT 6`

`#define CAL6_MASK 64`

##### CAL7 - Oscillator Calibration Value Bit7

`#define CAL7_BIT 7`

`#define CAL7_MASK 128`

### CLKPR -

`sfrb CLKPR = $61;`

##### CLKPS0

`#define CLKPS0_BIT 0`

`#define CLKPS0_MASK 1`

##### CLKPS1

`#define CLKPS1_BIT 1`

`#define CLKPS1_MASK 2`

##### CLKPS2

`#define CLKPS2_BIT 2`

`#define CLKPS2_MASK 4`

##### CLKPS3

`#define CLKPS3_BIT 3`

`#define CLKPS3_MASK 8`

##### CLKPCE

`#define CLKPCE_BIT 7`

`#define CLKPCE_MASK 128`

### SMCR - Sleep Mode Control Register

`sfrb SMCR = $33;`

##### SE - Sleep Enable

`#define SE_BIT 0`

`#define SE_MASK 1`

The SE bit must be written to logic one to make the MCU enter the sleep mode when the SLEEP instruction is executed.To

##### SM0 - Sleep Mode Select bit 0

`#define SM0_BIT 1`

`#define SM0_MASK 2`

These bits select between the five available sleep modes.

##### SM1 - Sleep Mode Select bit 1

`#define SM1_BIT 2`

`#define SM1_MASK 4`

These bits select between the five available sleep modes.

##### SM2 - Sleep Mode Select bit 2

`#define SM2_BIT 3`

`#define SM2_MASK 8`

These bits select between the five available sleep modes.

### EIND - Extended Indirect Register

`sfrb EIND = $3C;`

##### EIND0 - Bit 0

`#define EIND0_BIT 0`

`#define EIND0_MASK 1`

For EICALL/EIJMP instructions.

### RAMPZ - RAM Page Z Select Register

`sfrb RAMPZ = $3B;`

##### RAMPZ0 - RAM Page Z Select Register Bit 0

`#define RAMPZ0_BIT 0`

`#define RAMPZ0_MASK 1`

The RAMPZ register is normally used to select which 64K RAM Page is accessed by the Z pointer.

##### RAMPZ1 - RAM Page Z Select Register Bit 1

`#define RAMPZ1_BIT 1`

`#define RAMPZ1_MASK 2`

The RAMPZ register is normally used to select which 64K RAM Page is accessed by the Z pointer.

### GPIOR2 - General Purpose IO Register 2

`sfrb GPIOR2 = $2B;`

##### GPIOR20 - General Purpose IO Register 2 bit 0

`#define GPIOR20_BIT 0`

`#define GPIOR20_MASK 1`

##### GPIOR21 - General Purpose IO Register 2 bit 1

`#define GPIOR21_BIT 1`

`#define GPIOR21_MASK 2`

##### GPIOR22 - General Purpose IO Register 2 bit 2

`#define GPIOR22_BIT 2`

`#define GPIOR22_MASK 4`

##### GPIOR23 - General Purpose IO Register 2 bit 3

`#define GPIOR23_BIT 3`

`#define GPIOR23_MASK 8`

##### GPIOR24 - General Purpose IO Register 2 bit 4

`#define GPIOR24_BIT 4`

`#define GPIOR24_MASK 16`

##### GPIOR25 - General Purpose IO Register 2 bit 5

`#define GPIOR25_BIT 5`

`#define GPIOR25_MASK 32`

##### GPIOR26 - General Purpose IO Register 2 bit 6

`#define GPIOR26_BIT 6`

`#define GPIOR26_MASK 64`

##### GPIOR27 - General Purpose IO Register 2 bit 7

`#define GPIOR27_BIT 7`

`#define GPIOR27_MASK 128`

### GPIOR1 - General Purpose IO Register 1

`sfrb GPIOR1 = $2A;`

##### GPIOR10 - General Purpose IO Register 1 bit 0

`#define GPIOR10_BIT 0`

`#define GPIOR10_MASK 1`

##### GPIOR11 - General Purpose IO Register 1 bit 1

`#define GPIOR11_BIT 1`

`#define GPIOR11_MASK 2`

##### GPIOR12 - General Purpose IO Register 1 bit 2

`#define GPIOR12_BIT 2`

`#define GPIOR12_MASK 4`

##### GPIOR13 - General Purpose IO Register 1 bit 3

`#define GPIOR13_BIT 3`

`#define GPIOR13_MASK 8`

##### GPIOR14 - General Purpose IO Register 1 bit 4

`#define GPIOR14_BIT 4`

`#define GPIOR14_MASK 16`

##### GPIOR15 - General Purpose IO Register 1 bit 5

`#define GPIOR15_BIT 5`

`#define GPIOR15_MASK 32`

##### GPIOR16 - General Purpose IO Register 1 bit 6

`#define GPIOR16_BIT 6`

`#define GPIOR16_MASK 64`

##### GPIOR17 - General Purpose IO Register 1 bit 7

`#define GPIOR17_BIT 7`

`#define GPIOR17_MASK 128`

### GPIOR0 - General Purpose IO Register 0

`sfrb GPIOR0 = $1E;`

##### GPIOR00 - General Purpose IO Register 0 bit 0

`#define GPIOR00_BIT 0`

`#define GPIOR00_MASK 1`

##### GPIOR01 - General Purpose IO Register 0 bit 1

`#define GPIOR01_BIT 1`

`#define GPIOR01_MASK 2`

##### GPIOR02 - General Purpose IO Register 0 bit 2

`#define GPIOR02_BIT 2`

`#define GPIOR02_MASK 4`

##### GPIOR03 - General Purpose IO Register 0 bit 3

`#define GPIOR03_BIT 3`

`#define GPIOR03_MASK 8`

##### GPIOR04 - General Purpose IO Register 0 bit 4

`#define GPIOR04_BIT 4`

`#define GPIOR04_MASK 16`

##### GPIOR05 - General Purpose IO Register 0 bit 5

`#define GPIOR05_BIT 5`

`#define GPIOR05_MASK 32`

##### GPIOR06 - General Purpose IO Register 0 bit 6

`#define GPIOR06_BIT 6`

`#define GPIOR06_MASK 64`

##### GPIOR07 - General Purpose IO Register 0 bit 7

`#define GPIOR07_BIT 7`

`#define GPIOR07_MASK 128`

### PRR1 - Power Reduction Register1

`sfrb PRR1 = $65;`

##### PRUSART1 - Power Reduction USART1

`#define PRUSART1_BIT 0`

`#define PRUSART1_MASK 1`

##### PRUSART2 - Power Reduction USART2

`#define PRUSART2_BIT 1`

`#define PRUSART2_MASK 2`

##### PRUSART3 - Power Reduction USART3

`#define PRUSART3_BIT 2`

`#define PRUSART3_MASK 4`

##### PRTIM3 - Power Reduction Timer/Counter3

`#define PRTIM3_BIT 3`

`#define PRTIM3_MASK 8`

##### PRTIM4 - Power Reduction Timer/Counter4

`#define PRTIM4_BIT 4`

`#define PRTIM4_MASK 16`

##### PRTIM5 - Power Reduction Timer/Counter5

`#define PRTIM5_BIT 5`

`#define PRTIM5_MASK 32`

### PRR0 - Power Reduction Register0

`sfrb PRR0 = $64;`

##### PRADC - Power Reduction ADC

`#define PRADC_BIT 0`

`#define PRADC_MASK 1`

##### PRUSART0 - Power Reduction USART

`#define PRUSART0_BIT 1`

`#define PRUSART0_MASK 2`

##### PRSPI - Power Reduction Serial Peripheral Interface

`#define PRSPI_BIT 2`

`#define PRSPI_MASK 4`

##### PRTIM1 - Power Reduction Timer/Counter1

`#define PRTIM1_BIT 3`

`#define PRTIM1_MASK 8`

##### PRTIM0 - Power Reduction Timer/Counter0

`#define PRTIM0_BIT 5`

`#define PRTIM0_MASK 32`

##### PRTIM2 - Power Reduction Timer/Counter2

`#define PRTIM2_BIT 6`

`#define PRTIM2_MASK 64`

##### PRTWI - Power Reduction TWI

`#define PRTWI_BIT 7`

`#define PRTWI_MASK 128`

## AD CONVERTER

AD Converter Feature list: 10-bit Resolution. 0.5 LSB Integral Non-Linearity. +-2 LSB Absolute Accuracy. TBD - 260 µs Conversion Time. Up to TBD kSPS at maximum resolution. 8 Multiplexed Single Ended Input Channels. 7 Differential input channels (TQFP package only). 2 Differential input channels with optional gain of 10x and 200x (TQFP package only). Optional left adjustment for ADC result readout. 0 - VCC ADC Input Voltage Range. Selectable 2.56 V ADC reference voltage. Free Running or Single Conversion Mode. Interrupt on ADC Conversion Complete. Sleep Mode No

### ADMUX - The ADC multiplexer Selection Register

`sfrb ADMUX = $7C;`

##### MUX0 - Analog Channel and Gain Selection Bits

`#define MUX0_BIT 0`

`#define MUX0_MASK 1`

The value of these bits selects which combination of analog inputs are connected to the ADC. These bits also select the gain for the differential channels. See Table 92 for details. If these bits are changed during a conversion, the change will not go in effect until this conversion is complete (ADIF in ADCSR is set).

##### MUX1 - Analog Channel and Gain Selection Bits

`#define MUX1_BIT 1`

`#define MUX1_MASK 2`

The value of these bits selects which combination of analog inputs are connected to the ADC. These bits also select the gain for the differential channels. See Table 92 for details. If these bits are changed during a conversion, the change will not go in effect until this conversion is complete (ADIF in ADCSR is set).

##### MUX2 - Analog Channel and Gain Selection Bits

`#define MUX2_BIT 2`

`#define MUX2_MASK 4`

The value of these bits selects which combination of analog inputs are connected to the ADC. These bits also select the gain for the differential channels. See Table 92 for details. If these bits are changed during a conversion, the change will not go in effect until this conversion is complete (ADIF in ADCSR is set).

##### MUX3 - Analog Channel and Gain Selection Bits

`#define MUX3_BIT 3`

`#define MUX3_MASK 8`

The value of these bits selects which combination of analog inputs are connected to the ADC. These bits also select the gain for the differential channels. See Table 92 for details. If these bits are changed during a conversion, the change will not go in effect until this conversion is complete (ADIF in ADCSR is set).

##### MUX4 - Analog Channel and Gain Selection Bits

`#define MUX4_BIT 4`

`#define MUX4_MASK 16`

The value of these bits selects which combination of analog inputs are connected to the ADC. These bits also select the gain for the differential channels. See Table 92 for details. If these bits are changed during a conversion, the change will not go in effect until this conversion is complete (ADIF in ADCSR is set).

##### ADLAR - Left Adjust Result

`#define ADLAR_BIT 5`

`#define ADLAR_MASK 32`

The ADLAR bit affects the presentation of the ADC conversion result in the ADC data register. If ADLAR is cleared, the result is right adjusted. If ADLAR is set, the result is left adjusted. Changing the ADLAR bit will affect the ADC data register immediately, regardless of any ongoing conversions. For a complete description of this bit, see ?The ADC Data Register -ADCL and ADCH? on page 198.

##### REFS0 - Reference Selection Bit 0

`#define REFS0_BIT 6`

`#define REFS0_MASK 64`

These bits select the voltage reference for the ADC, as shown in Table 91. If these bits are changed during a conversion, the change will not go in effect until this conversion is complete (ADIF in ADCSR is set). If differential channels are used, the selected reference should not be closer to AV CC than indicated in Table 94 on page 200. The internal voltage reference options may not be used if an external reference voltage is being applied to the AREF pin.

##### REFS1 - Reference Selection Bit 1

`#define REFS1_BIT 7`

`#define REFS1_MASK 128`

These bits select the voltage reference for the ADC, as shown in Table 91. If these bits are changed during a conversion, the change will not go in effect until this conversion is complete (ADIF in ADCSR is set). If differential channels are used, the selected reference should not be closer to AV CC than indicated in Table 94 on page 200. The internal voltage reference options may not be used if an external reference voltage is being applied to the AREF pin.

### ADCH - ADC Data Register High Byte

`sfrb ADCH = $79;`

##### ADCH0 - ADC Data Register High Byte Bit 0

`#define ADCH0_BIT 0`

`#define ADCH0_MASK 1`

##### ADCH1 - ADC Data Register High Byte Bit 1

`#define ADCH1_BIT 1`

`#define ADCH1_MASK 2`

##### ADCH2 - ADC Data Register High Byte Bit 2

`#define ADCH2_BIT 2`

`#define ADCH2_MASK 4`

##### ADCH3 - ADC Data Register High Byte Bit 3

`#define ADCH3_BIT 3`

`#define ADCH3_MASK 8`

##### ADCH4 - ADC Data Register High Byte Bit 4

`#define ADCH4_BIT 4`

`#define ADCH4_MASK 16`

##### ADCH5 - ADC Data Register High Byte Bit 5

`#define ADCH5_BIT 5`

`#define ADCH5_MASK 32`

##### ADCH6 - ADC Data Register High Byte Bit 6

`#define ADCH6_BIT 6`

`#define ADCH6_MASK 64`

##### ADCH7 - ADC Data Register High Byte Bit 7

`#define ADCH7_BIT 7`

`#define ADCH7_MASK 128`

### ADCL - ADC Data Register Low Byte

`sfrb ADCL = $78;`

##### ADCL0 - ADC Data Register Low Byte Bit 0

`#define ADCL0_BIT 0`

`#define ADCL0_MASK 1`

##### ADCL1 - ADC Data Register Low Byte Bit 1

`#define ADCL1_BIT 1`

`#define ADCL1_MASK 2`

##### ADCL2 - ADC Data Register Low Byte Bit 2

`#define ADCL2_BIT 2`

`#define ADCL2_MASK 4`

##### ADCL3 - ADC Data Register Low Byte Bit 3

`#define ADCL3_BIT 3`

`#define ADCL3_MASK 8`

##### ADCL4 - ADC Data Register Low Byte Bit 4

`#define ADCL4_BIT 4`

`#define ADCL4_MASK 16`

##### ADCL5 - ADC Data Register Low Byte Bit 5

`#define ADCL5_BIT 5`

`#define ADCL5_MASK 32`

##### ADCL6 - ADC Data Register Low Byte Bit 6

`#define ADCL6_BIT 6`

`#define ADCL6_MASK 64`

##### ADCL7 - ADC Data Register Low Byte Bit 7

`#define ADCL7_BIT 7`

`#define ADCL7_MASK 128`

### ADCSRA - The ADC Control and Status register A

`sfrb ADCSRA = $7A;`

##### ADPS0 - ADC Prescaler Select Bits

`#define ADPS0_BIT 0`

`#define ADPS0_MASK 1`

These bits determine the division factor between the XTAL frequency and the input clock to the ADC.

##### ADPS1 - ADC Prescaler Select Bits

`#define ADPS1_BIT 1`

`#define ADPS1_MASK 2`

These bits determine the division factor between the XTAL frequency and the input clock to the ADC.

##### ADPS2 - ADC Prescaler Select Bits

`#define ADPS2_BIT 2`

`#define ADPS2_MASK 4`

These bits determine the division factor between the XTAL frequency and the input clock to the ADC.

##### ADIE - ADC Interrupt Enable

`#define ADIE_BIT 3`

`#define ADIE_MASK 8`

When this bit is set (one) and the I-bit in SREG is set (one), the ADC Conversion Complete Interrupt is activated.

##### ADIF - ADC Interrupt Flag

`#define ADIF_BIT 4`

`#define ADIF_MASK 16`

This bit is set (one) when an ADC conversion completes and the data registers are updated. The ADC Conversion Complete Interrupt is executed if the ADIE bit and the I-bit in SREG are set (one). ADIF is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, ADIF is cleared by writing a logical one to the flag. Beware that if doing a read-modify-write on ADCSR, a pending interrupt can be disabled. This also applies if the SBI and CBI instructions are used.

##### ADATE - ADC Auto Trigger Enable

`#define ADATE_BIT 5`

`#define ADATE_MASK 32`

When this bit is written to one, Auto Triggering of the ADC is enabled. The ADC will start a conversion on a positive edge of the selected trigger signal. The trigger source is selected by setting the ADC Trigger Select bits, ADTS in ADCSRB.

##### ADSC - ADC Start Conversion

`#define ADSC_BIT 6`

`#define ADSC_MASK 64`

In Single Conversion Mode, a logical ?1? must be written to this bit to start each conversion. In Free Running Mode, a logical ?1? must be written to this bit to start the first conversion. The first time ADSC has been written after the ADC has been enabled, or if ADSC is written at the same time as the ADC is enabled, an extended conversion will result. This extended conversion performs initialization of the ADC. ADSC will read as one as long as a conversion is in progress. When the conversion is complete, it returns to zero. When a dummy conversion precedes a real conversion, ADSC will stay high until the real conversion completes. Writing a 0 to this bit has no effect

##### ADEN - ADC Enable

`#define ADEN_BIT 7`

`#define ADEN_MASK 128`

Writing a logical ?1? to this bit enables the ADC. By clearing this bit to zero, the ADC is turned off. Turning the ADC off while a conversion is in progress, will terminate this conversion.

### ADCSRB - The ADC Control and Status register B

`sfrb ADCSRB = $7B;`

##### ADTS0 - ADC Auto Trigger Source bit 0

`#define ADTS0_BIT 0`

`#define ADTS0_MASK 1`

Please refer to table on page 240 in datasheet for trigger selection.

##### ADTS1 - ADC Auto Trigger Source bit 1

`#define ADTS1_BIT 1`

`#define ADTS1_MASK 2`

Please refer to table on page 240 in datasheet for trigger selection.

##### ADTS2 - ADC Auto Trigger Source bit 2

`#define ADTS2_BIT 2`

`#define ADTS2_MASK 4`

Please refer to table on page 240 in datasheet for trigger selection.

##### MUX5 - Analog Channel and Gain Selection Bits

`#define MUX5_BIT 3`

`#define MUX5_MASK 8`

The value of these bits selects which combination of analog inputs are connected to the ADC. These bits also select the gain for the differential channels. See Table 92 for details. If these bits are changed during a conversion, the change will not go in effect until this conversion is complete (ADIF in ADCSR is set).

##### ACME

`#define ACME_BIT 6`

`#define ACME_MASK 64`

### DIDR2 - Digital Input Disable Register

`sfrb DIDR2 = $7D;`

##### ADC8D

`#define ADC8D_BIT 0`

`#define ADC8D_MASK 1`

##### ADC9D

`#define ADC9D_BIT 1`

`#define ADC9D_MASK 2`

##### ADC10D

`#define ADC10D_BIT 2`

`#define ADC10D_MASK 4`

##### ADC11D

`#define ADC11D_BIT 3`

`#define ADC11D_MASK 8`

##### ADC12D

`#define ADC12D_BIT 4`

`#define ADC12D_MASK 16`

##### ADC13D

`#define ADC13D_BIT 5`

`#define ADC13D_MASK 32`

##### ADC14D

`#define ADC14D_BIT 6`

`#define ADC14D_MASK 64`

##### ADC15D

`#define ADC15D_BIT 7`

`#define ADC15D_MASK 128`

### DIDR0 - Digital Input Disable Register

`sfrb DIDR0 = $7E;`

##### ADC0D

`#define ADC0D_BIT 0`

`#define ADC0D_MASK 1`

##### ADC1D

`#define ADC1D_BIT 1`

`#define ADC1D_MASK 2`

##### ADC2D

`#define ADC2D_BIT 2`

`#define ADC2D_MASK 4`

##### ADC3D

`#define ADC3D_BIT 3`

`#define ADC3D_MASK 8`

##### ADC4D

`#define ADC4D_BIT 4`

`#define ADC4D_MASK 16`

##### ADC5D

`#define ADC5D_BIT 5`

`#define ADC5D_MASK 32`

##### ADC6D

`#define ADC6D_BIT 6`

`#define ADC6D_MASK 64`

##### ADC7D

`#define ADC7D_BIT 7`

`#define ADC7D_MASK 128`

## BOOT LOAD

The Boot Loader Support provides a real Read While Write self-programming mechanism for downloading and uploading program code by the MCU itself. This feature allows flexible application software updates controlled by the MCU using a Flash-resident Boot Loader program. The Boot Loader program can use any available data interface and associated proto-col to read code and write (program) that code into the Flash memory, or read the code from the program memory. The program code within the Boot Loader section has the capability to write into the entire Flash, including the Boot Loader Memory. The Boot Loader can thus even modify itself, and it can also erase itself from the code if the feature is not needed anymore. The size of the Boot Loader Memory is configurable with fuses and the Boot Loader has two separate sets of Boot Lock Bits which can be set independently. This gives the user a unique flexibility to select different levels of protection. Boot Loader Features: Read While Write self-programming. Flexibl Boot Memory size. High security (separate Boot Lock bits for a flexible protection). Separate fuse to select reset vector Optimized page (1) size. Code efficient algorithm Efficient read-modify-write suppor

### SPMCSR - Store Program Memory Control Register

`sfrb SPMCSR = $37;`

##### SPMEN - Store Program Memory Enable

`#define SPMEN_BIT 0`

`#define SPMEN_MASK 1`

This bit enables the SPM instruction for the next four clock cycles. If written to one together with either RWWSRE, BLB-SET, PGWRT or PGERS, the following SPM instruction will have a special meaning, see description above. If only SPMEN is written, the following SPM instruction will store the value in R1:R0 in the temporary page buffer addressed by the Z pointer. The LSB of the Z pointer is ignored. The SPMEN bit will auto-clear upon completion of an SPM instruction, or if no SPM instruction is executed within four clock cycles. During page erase and page write, the SPMEN bit remain high until the operation is completed. Writing any other combination than ?10001?, "01001", "00101", "00011" or "00001" in the lower five bits will have no effec

##### PGERS - Page Erase

`#define PGERS_BIT 1`

`#define PGERS_MASK 2`

If this bit is written to one at the same time as SPMEN, the next SPM instruction within four clock cycles executes page erase. The page address is taken from the high part of the Z pointer. The data in R1 and R0 are ignored. The PGERS bit will auto-clear upon completion of a page erase, or if no SPM instruction is executed within four clock cycles. The CPU is halted during the entire page write operation if the NRWW section is addressed.

##### PGWRT - Page Write

`#define PGWRT_BIT 2`

`#define PGWRT_MASK 4`

If this bit is written to one at the same time as SPMEN, the next SPM instruction within four clock cycles executes page write, with the data stored in the temporary buffer. The page address is taken from the high part of the Z pointer. The data in R1 and R0 are ignored. The PGWRT bit will auto-clear upon completion of a page write, or if no SPM instruction is exe-cuted within four clock cycles. The CPU is halted during the entire page write operation if the NRWW section is addressed.

##### BLBSET - Boot Lock Bit Set

`#define BLBSET_BIT 3`

`#define BLBSET_MASK 8`

If this bit is written to one at the same time as SPMEN, the next SPM instruction within four clock cycles sets Boot Lock bits, according to the data in R0. The data in R1 and the address in the Z pointer are ignored. The BLBSET bit will automatically be cleared upon completion of the lock bit set, or if no SPM instruction is executed within four clock cycles. An LPM instruction within three cycles after BLBSET and SPMEN are set in the SPMCR register, will read either the Lock-bits or the Fuse bits (depending on Z0 in the Z pointer) into the destination register. See ?Reading the Fuse and Lock Bits from Software? on page 235 for details

##### RWWSRE - Read While Write section read enable

`#define RWWSRE_BIT 4`

`#define RWWSRE_MASK 16`

When programming (page erase or page write) to the RWW section, the RWW section is blocked for reading (the RWWSB will be set by hardware). To re-enable the RWW section, the user software must wait until the programming is completed (SPMEN will be cleared). Then, if the RWWSRE bit is written to one at the same time as SPMEN, the next SPM instruction within four clock cycles re-enables the RWW section. The RWW section cannot be re-enabled while Flash is busy with a page erase or a page write (SPMEN is set). If the RWWSRE bit is written while the Flash is being loaded, the Flash load operation will abort and the data loaded will be lo

##### SIGRD - Signature Row Read

`#define SIGRD_BIT 5`

`#define SIGRD_MASK 32`

If this bit is written to one at the same time as SPMEN, the next LPM instruction within three clock cycles will read a byte from the signature row into the destination register. see ?Reading the Signature Row from Software? in the datasheet for details. An SPM instruction within four cycles after SIGRD and SPMEN are set will have no effect. This operation is reserved for future use and should not be used.

##### RWWSB - Read While Write Section Busy

`#define RWWSB_BIT 6`

`#define RWWSB_MASK 64`

When a self-programming (page erase or page write) operation to the RWW section is initiated, the RWWSB will be set (one) by hardware. When the RWWSB bit is set, the RWW section cannot be accessed. The RWWSB bit will be cleared if the RWWSRE bit is written to one after a self-programming operation is completed. Alternatively the RWWSB bit will auto-matically be cleared if a page load operation is initiated.

##### SPMIE - SPM Interrupt Enable

`#define SPMIE_BIT 7`

`#define SPMIE_MASK 128`

When the SPMIE bit is written to one, and the I-bit in the Status Register is set (one), the SPM ready interrupt will be enabled. The SPM ready Interrupt will be executed as long as the SPMEN bit in the SPMCR register is cleared.

## USART2

The Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is a highly flexible serial communication device. The main features are: ? Full Duplex Operation (Independent Serial Receive and Transmit Registers) ? Asynchronous or Synchronous Operation ? Master or Slave Clocked Synchronous Operation ? High Resolution Baud Rate Generator ? Supports Serial Frames with 5, 6, 7, 8 or 9 Data Bits and 1 or 2 Stop Bits ? Odd or Even Parity Generation and Parity Check Supported by Hardware ? Data OverRun Detection ? Framing Error Detection ? Noise Filtering Includes False Start Bit Detection and Digital Low Pass Filter ? Three Separate Interrupts on TX Complete, TX Data Register Empty and RX Complete ? Multi-processor Communication Mode ? Double Speed Asynchronous Communica

### UDR2 - USART I/O Data Register

`sfrb UDR2 = $D6;`

##### UDR2-0 - USART I/O Data Register bit 0

`#define UDR2-0_BIT 0`

`#define UDR2-0_MASK 1`

##### UDR2-1 - USART I/O Data Register bit 1

`#define UDR2-1_BIT 1`

`#define UDR2-1_MASK 2`

##### UDR2-2 - USART I/O Data Register bit 2

`#define UDR2-2_BIT 2`

`#define UDR2-2_MASK 4`

##### UDR2-3 - USART I/O Data Register bit 3

`#define UDR2-3_BIT 3`

`#define UDR2-3_MASK 8`

##### UDR2-4 - USART I/O Data Register bit 4

`#define UDR2-4_BIT 4`

`#define UDR2-4_MASK 16`

##### UDR2-5 - USART I/O Data Register bit 5

`#define UDR2-5_BIT 5`

`#define UDR2-5_MASK 32`

##### UDR2-6 - USART I/O Data Register bit 6

`#define UDR2-6_BIT 6`

`#define UDR2-6_MASK 64`

##### UDR2-7 - USART I/O Data Register bit 7

`#define UDR2-7_BIT 7`

`#define UDR2-7_MASK 128`

### UCSR2A - USART Control and Status Register A

`sfrb UCSR2A = $D0;`

##### MPCM2 - Multi-processor Communication Mode

`#define MPCM2_BIT 0`

`#define MPCM2_MASK 1`

This bit enables the Multi-processor Communication Mode. When the MPCM bit is written to one, all the incoming frames received by the USART receiver that do not contain address information will be ignored. The transmitter is unaffected by the MPCM setting. For more detailed information see ?Multi-processor Communication Mode? on page 152.

##### U2X2 - Double the USART transmission speed

`#define U2X2_BIT 1`

`#define U2X2_MASK 2`

This bit only has effect for the asynchronous operation. Write this bit to zero when using synchronous operation. Writing this bit to one will reduce the divisor of the baud rate divider from 16 to 8 effectively doubling the transfer rate for asynchronous communication.

##### UPE2 - Parity Error

`#define UPE2_BIT 2`

`#define UPE2_MASK 4`

This bit is set if the next character in the receive buffer had a Parity Error when received and the parity checking was enabled at that point (UPM1 = 1). This bit is valid until the receive buffer (UDR0) is read. Always set this bit to zero when writing to UCSR0A.

##### DOR2 - Data overRun

`#define DOR2_BIT 3`

`#define DOR2_MASK 8`

This bit is set if an Overrun condition is detected, i.e. when a character already present in the UDRregister is not read before the next character has been shifted into the Receiver Shift register. The OR bit is buffered, which means that it will be set once the valid data still in UDR0E is read. The OR bit is cleared (zero) when data is received and transferred to UDR0.

##### FE2 - Framing Error

`#define FE2_BIT 4`

`#define FE2_MASK 16`

This bit is set if a Framing Error condition is detected, i.e. when the stop bit of an incoming character is zero. The FE bit is cleared when the stop bit of received data is one.

##### UDRE2 - USART Data Register Empty

`#define UDRE2_BIT 5`

`#define UDRE2_MASK 32`

This bit is set (one) when a character written to UDRis transferred to the Transmit shift register. Setting of this bit indicates that the transmitter is ready to receive a new character for transmission. When the UDR0IE bit in UCR is set, the USART Transmit Complete interrupt to be executed as long as UDR0E is set. UDR0E is cleared by writing UDR0. When interrupt-driven data transmittal is used, the USART Data Register Empty Interrupt routine must write UDRin order to clear UDR0E, otherwise a new interrupt will occur once the interrupt routine terminates. UDR0E is set (one) during reset to indicate that the transmitter is re

##### TXC2 - USART Transmitt Complete

`#define TXC2_BIT 6`

`#define TXC2_MASK 64`

This bit is set (one) when the entire character (including the stop bit) in the Transmit Shift register has been shifted out and no new data has been written to UDR0. This flag is especially useful in half-duplex communications interfaces, where a transmitting application must enter receive mode and free the communications bus immediately after completing the transmission. When the TXCIE bit in UCR is set, setting of TXC causes the USART Transmit Complete interrupt to be executed. TXC is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, the TXC bit is cleared (zero) by writing a logical one to the b

##### RXC2 - USART Receive Complete

`#define RXC2_BIT 7`

`#define RXC2_MASK 128`

This bit is set (one) when a received character is transferred from the Receiver Shift register to UDR0. The bit is set regard-less of any detected framing errors. When the RXCIE bit in UCR is set, the USART Receive Complete interrupt will be executed when RXC is set(one). RXC is cleared by reading UDR0. When interrupt-driven data reception is used, the USART Receive Complete Interrupt routine must read UDRin order to clear RXC, otherwise a new interrupt will occur once the interrupt routine terminates.

### UCSR2B - USART Control and Status Register B

`sfrb UCSR2B = $D1;`

##### TXB82 - Transmit Data Bit 8

`#define TXB82_BIT 0`

`#define TXB82_MASK 1`

TXB8 is the 9th data bit in the character to be transmitted when operating with serial frames with 9 data bits. Must be writ-ten before writing the low bits to UDR0.

##### RXB82 - Receive Data Bit 8

`#define RXB82_BIT 1`

`#define RXB82_MASK 2`

RXB8 is the 9th data bit of the received character when operating with serial frames with 9 data bits. Must be read before reading the low bits from UDR0.

##### UCSZ22 - Character Size

`#define UCSZ22_BIT 2`

`#define UCSZ22_MASK 4`

The UCSZ2 bits combined with the UCSZ1:0 bit in UCSR0C sets the number of data bits (character size) in a frame the receiver and transmitter use.

##### TXEN2 - Transmitter Enable

`#define TXEN2_BIT 3`

`#define TXEN2_MASK 8`

Writing this bit to one enables the USART transmitter. The transmitter will override normal port operation for the TxD pin when enabled. The disabling of the transmitter (writing TXEN to zero) will not become effective until ongoing and pending transmissions are completed, i.e. when the transmit shift register and transmit buffer register does not contain data to be transmitted. When disabled, the transmitter will no longer override the TxD port.

##### RXEN2 - Receiver Enable

`#define RXEN2_BIT 4`

`#define RXEN2_MASK 16`

Writing this bit to one enables the USART receiver. The receiver will override normal port operation for the RxD pin when enabled. Disabling the receiver will flush the receive buffer invalidating the FE, DOR and PE flags.

##### UDRIE2 - USART Data register Empty Interrupt Enable

`#define UDRIE2_BIT 5`

`#define UDRIE2_MASK 32`

Writing this bit to one enables interrupt on the UDR0E flag. A Data Register Empty interrupt will be generated only if the UDR0IE bit is written to one, the global interrupt flag in SREG is written to one and the UDR0E bit in UCSR0A is set.

##### TXCIE2 - TX Complete Interrupt Enable

`#define TXCIE2_BIT 6`

`#define TXCIE2_MASK 64`

Writing this bit to one enables interrupt on the TXC flag. A USART Transmit Complete interrupt will be generated only if the TXCIE bit is written to one, the global interrupt flag in SREG is written to one and the TXC bit in UCSR0A is set.

##### RXCIE2 - RX Complete Interrupt Enable

`#define RXCIE2_BIT 7`

`#define RXCIE2_MASK 128`

Writing this bit to one enables interrupt on the RXC flag. A USART Receive Complete interrupt will be generated only if the RXCIE bit is written to one, the global interrupt flag in SREG is written to one and the RXC bit in UCSR0A is set.

### UCSR2C - USART Control and Status Register C

`sfrb UCSR2C = $D2;`

##### UCPOL2 - Clock Polarity

`#define UCPOL2_BIT 0`

`#define UCPOL2_MASK 1`

This bit is used for synchronous mode only. Write this bit to zero when asynchronous mode is used. The UCPOL bit sets the relationship between data output change and data input sample, and the synchronous clock (XCK).

##### UCSZ20 - Character Size

`#define UCSZ20_BIT 1`

`#define UCSZ20_MASK 2`

Character Size: 0 0 0 = 5-bit. 0 0 1 = 6-bit. 0 1 0 = 7 bit. 0 1 1 = 8-bit. 1 1 1 = 9 bit.

##### UCSZ21 - Character Size

`#define UCSZ21_BIT 2`

`#define UCSZ21_MASK 4`

Character Size: 0 0 0 = 5-bit. 0 0 1 = 6-bit. 0 1 0 = 7 bit. 0 1 1 = 8-bit. 1 1 1 = 9 bit.

##### USBS2 - Stop Bit Select

`#define USBS2_BIT 3`

`#define USBS2_MASK 8`

0: 1-bit. 1: 2-bit.

##### UPM20 - Parity Mode Bit 0

`#define UPM20_BIT 4`

`#define UPM20_MASK 16`

This bit enable and set type of parity generation and check. If enabled, the transmitter will automatically generate and send the parity of the transmitted data bits within each frame. The receiver will generate a parity value for the incoming data and compare it to the UPM0 setting. If a mismatch is detected, the PE flag in UCSR0A will be set.

##### UPM21 - Parity Mode Bit 1

`#define UPM21_BIT 5`

`#define UPM21_MASK 32`

This bit enable and set type of parity generation and check. If enabled, the transmitter will automatically generate and send the parity of the transmitted data bits within each frame. The receiver will generate a parity value for the incoming data and compare it to the UPM0 setting. If a mismatch is detected, the PE flag in UCSR0A will be set.

##### UMSEL20 - USART Mode Select

`#define UMSEL20_BIT 6`

`#define UMSEL20_MASK 64`

##### UMSEL21 - USART Mode Select

`#define UMSEL21_BIT 7`

`#define UMSEL21_MASK 128`

### UBRR2H - USART Baud Rate Register High Byte

`sfrb UBRR2H = $D5;`

##### UBRR8 - USART Baud Rate Register bit 8

`#define UBRR8_BIT 0`

`#define UBRR8_MASK 1`

##### UBRR9 - USART Baud Rate Register bit 9

`#define UBRR9_BIT 1`

`#define UBRR9_MASK 2`

##### UBRR10 - USART Baud Rate Register bit 10

`#define UBRR10_BIT 2`

`#define UBRR10_MASK 4`

##### UBRR11 - USART Baud Rate Register bit 11

`#define UBRR11_BIT 3`

`#define UBRR11_MASK 8`

### UBRR2L - USART Baud Rate Register Low Byte

`sfrb UBRR2L = $D4;`

##### UBRR0 - USART Baud Rate Register bit 0

`#define UBRR0_BIT 0`

`#define UBRR0_MASK 1`

##### UBRR1 - USART Baud Rate Register bit 1

`#define UBRR1_BIT 1`

`#define UBRR1_MASK 2`

##### UBRR2 - USART Baud Rate Register bit 2

`#define UBRR2_BIT 2`

`#define UBRR2_MASK 4`

##### UBRR3 - USART Baud Rate Register bit 3

`#define UBRR3_BIT 3`

`#define UBRR3_MASK 8`

##### UBRR4 - USART Baud Rate Register bit 4

`#define UBRR4_BIT 4`

`#define UBRR4_MASK 16`

##### UBRR5 - USART Baud Rate Register bit 5

`#define UBRR5_BIT 5`

`#define UBRR5_MASK 32`

##### UBRR6 - USART Baud Rate Register bit 6

`#define UBRR6_BIT 6`

`#define UBRR6_MASK 64`

##### UBRR7 - USART Baud Rate Register bit 7

`#define UBRR7_BIT 7`

`#define UBRR7_MASK 128`

## USART3

The Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is a highly flexible serial communication device. The main features are: ? Full Duplex Operation (Independent Serial Receive and Transmit Registers) ? Asynchronous or Synchronous Operation ? Master or Slave Clocked Synchronous Operation ? High Resolution Baud Rate Generator ? Supports Serial Frames with 5, 6, 7, 8 or 9 Data Bits and 1 or 2 Stop Bits ? Odd or Even Parity Generation and Parity Check Supported by Hardware ? Data OverRun Detection ? Framing Error Detection ? Noise Filtering Includes False Start Bit Detection and Digital Low Pass Filter ? Three Separate Interrupts on TX Complete, TX Data Register Empty and RX Complete ? Multi-processor Communication Mode ? Double Speed Asynchronous Communica

### UDR3 - USART I/O Data Register

`sfrb UDR3 = $136;`

##### UDR3-0 - USART I/O Data Register bit 0

`#define UDR3-0_BIT 0`

`#define UDR3-0_MASK 1`

##### UDR3-1 - USART I/O Data Register bit 1

`#define UDR3-1_BIT 1`

`#define UDR3-1_MASK 2`

##### UDR3-2 - USART I/O Data Register bit 2

`#define UDR3-2_BIT 2`

`#define UDR3-2_MASK 4`

##### UDR3-3 - USART I/O Data Register bit 3

`#define UDR3-3_BIT 3`

`#define UDR3-3_MASK 8`

##### UDR3-4 - USART I/O Data Register bit 4

`#define UDR3-4_BIT 4`

`#define UDR3-4_MASK 16`

##### UDR3-5 - USART I/O Data Register bit 5

`#define UDR3-5_BIT 5`

`#define UDR3-5_MASK 32`

##### UDR3-6 - USART I/O Data Register bit 6

`#define UDR3-6_BIT 6`

`#define UDR3-6_MASK 64`

##### UDR3-7 - USART I/O Data Register bit 7

`#define UDR3-7_BIT 7`

`#define UDR3-7_MASK 128`

### UCSR3A - USART Control and Status Register A

`sfrb UCSR3A = $130;`

##### MPCM3 - Multi-processor Communication Mode

`#define MPCM3_BIT 0`

`#define MPCM3_MASK 1`

This bit enables the Multi-processor Communication Mode. When the MPCM bit is written to one, all the incoming frames received by the USART receiver that do not contain address information will be ignored. The transmitter is unaffected by the MPCM setting. For more detailed information see ?Multi-processor Communication Mode? on page 152.

##### U2X3 - Double the USART transmission speed

`#define U2X3_BIT 1`

`#define U2X3_MASK 2`

This bit only has effect for the asynchronous operation. Write this bit to zero when using synchronous operation. Writing this bit to one will reduce the divisor of the baud rate divider from 16 to 8 effectively doubling the transfer rate for asynchronous communication.

##### UPE3 - Parity Error

`#define UPE3_BIT 2`

`#define UPE3_MASK 4`

This bit is set if the next character in the receive buffer had a Parity Error when received and the parity checking was enabled at that point (UPM1 = 1). This bit is valid until the receive buffer (UDR0) is read. Always set this bit to zero when writing to UCSR0A.

##### DOR3 - Data overRun

`#define DOR3_BIT 3`

`#define DOR3_MASK 8`

This bit is set if an Overrun condition is detected, i.e. when a character already present in the UDRregister is not read before the next character has been shifted into the Receiver Shift register. The OR bit is buffered, which means that it will be set once the valid data still in UDR0E is read. The OR bit is cleared (zero) when data is received and transferred to UDR0.

##### FE3 - Framing Error

`#define FE3_BIT 4`

`#define FE3_MASK 16`

This bit is set if a Framing Error condition is detected, i.e. when the stop bit of an incoming character is zero. The FE bit is cleared when the stop bit of received data is one.

##### UDRE3 - USART Data Register Empty

`#define UDRE3_BIT 5`

`#define UDRE3_MASK 32`

This bit is set (one) when a character written to UDRis transferred to the Transmit shift register. Setting of this bit indicates that the transmitter is ready to receive a new character for transmission. When the UDR0IE bit in UCR is set, the USART Transmit Complete interrupt to be executed as long as UDR0E is set. UDR0E is cleared by writing UDR0. When interrupt-driven data transmittal is used, the USART Data Register Empty Interrupt routine must write UDRin order to clear UDR0E, otherwise a new interrupt will occur once the interrupt routine terminates. UDR0E is set (one) during reset to indicate that the transmitter is re

##### TXC3 - USART Transmitt Complete

`#define TXC3_BIT 6`

`#define TXC3_MASK 64`

This bit is set (one) when the entire character (including the stop bit) in the Transmit Shift register has been shifted out and no new data has been written to UDR0. This flag is especially useful in half-duplex communications interfaces, where a transmitting application must enter receive mode and free the communications bus immediately after completing the transmission. When the TXCIE bit in UCR is set, setting of TXC causes the USART Transmit Complete interrupt to be executed. TXC is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, the TXC bit is cleared (zero) by writing a logical one to the b

##### RXC3 - USART Receive Complete

`#define RXC3_BIT 7`

`#define RXC3_MASK 128`

This bit is set (one) when a received character is transferred from the Receiver Shift register to UDR0. The bit is set regard-less of any detected framing errors. When the RXCIE bit in UCR is set, the USART Receive Complete interrupt will be executed when RXC is set(one). RXC is cleared by reading UDR0. When interrupt-driven data reception is used, the USART Receive Complete Interrupt routine must read UDRin order to clear RXC, otherwise a new interrupt will occur once the interrupt routine terminates.

### UCSR3B - USART Control and Status Register B

`sfrb UCSR3B = $131;`

##### TXB83 - Transmit Data Bit 8

`#define TXB83_BIT 0`

`#define TXB83_MASK 1`

TXB8 is the 9th data bit in the character to be transmitted when operating with serial frames with 9 data bits. Must be writ-ten before writing the low bits to UDR0.

##### RXB83 - Receive Data Bit 8

`#define RXB83_BIT 1`

`#define RXB83_MASK 2`

RXB8 is the 9th data bit of the received character when operating with serial frames with 9 data bits. Must be read before reading the low bits from UDR0.

##### UCSZ32 - Character Size

`#define UCSZ32_BIT 2`

`#define UCSZ32_MASK 4`

The UCSZ3 bits combined with the UCSZ1:0 bit in UCSR0C sets the number of data bits (character size) in a frame the receiver and transmitter use.

##### TXEN3 - Transmitter Enable

`#define TXEN3_BIT 3`

`#define TXEN3_MASK 8`

Writing this bit to one enables the USART transmitter. The transmitter will override normal port operation for the TxD pin when enabled. The disabling of the transmitter (writing TXEN to zero) will not become effective until ongoing and pending transmissions are completed, i.e. when the transmit shift register and transmit buffer register does not contain data to be transmitted. When disabled, the transmitter will no longer override the TxD port.

##### RXEN3 - Receiver Enable

`#define RXEN3_BIT 4`

`#define RXEN3_MASK 16`

Writing this bit to one enables the USART receiver. The receiver will override normal port operation for the RxD pin when enabled. Disabling the receiver will flush the receive buffer invalidating the FE, DOR and PE flags.

##### UDRIE3 - USART Data register Empty Interrupt Enable

`#define UDRIE3_BIT 5`

`#define UDRIE3_MASK 32`

Writing this bit to one enables interrupt on the UDR0E flag. A Data Register Empty interrupt will be generated only if the UDR0IE bit is written to one, the global interrupt flag in SREG is written to one and the UDR0E bit in UCSR0A is set.

##### TXCIE3 - TX Complete Interrupt Enable

`#define TXCIE3_BIT 6`

`#define TXCIE3_MASK 64`

Writing this bit to one enables interrupt on the TXC flag. A USART Transmit Complete interrupt will be generated only if the TXCIE bit is written to one, the global interrupt flag in SREG is written to one and the TXC bit in UCSR0A is set.

##### RXCIE3 - RX Complete Interrupt Enable

`#define RXCIE3_BIT 7`

`#define RXCIE3_MASK 128`

Writing this bit to one enables interrupt on the RXC flag. A USART Receive Complete interrupt will be generated only if the RXCIE bit is written to one, the global interrupt flag in SREG is written to one and the RXC bit in UCSR0A is set.

### UCSR3C - USART Control and Status Register C

`sfrb UCSR3C = $132;`

##### UCPOL3 - Clock Polarity

`#define UCPOL3_BIT 0`

`#define UCPOL3_MASK 1`

This bit is used for synchronous mode only. Write this bit to zero when asynchronous mode is used. The UCPOL bit sets the relationship between data output change and data input sample, and the synchronous clock (XCK).

##### UCSZ30 - Character Size

`#define UCSZ30_BIT 1`

`#define UCSZ30_MASK 2`

Character Size: 0 0 0 = 5-bit. 0 0 1 = 6-bit. 0 1 0 = 7 bit. 0 1 1 = 8-bit. 1 1 1 = 9 bit.

##### UCSZ31 - Character Size

`#define UCSZ31_BIT 2`

`#define UCSZ31_MASK 4`

Character Size: 0 0 0 = 5-bit. 0 0 1 = 6-bit. 0 1 0 = 7 bit. 0 1 1 = 8-bit. 1 1 1 = 9 bit.

##### USBS3 - Stop Bit Select

`#define USBS3_BIT 3`

`#define USBS3_MASK 8`

0: 1-bit. 1: 2-bit.

##### UPM30 - Parity Mode Bit 0

`#define UPM30_BIT 4`

`#define UPM30_MASK 16`

This bit enable and set type of parity generation and check. If enabled, the transmitter will automatically generate and send the parity of the transmitted data bits within each frame. The receiver will generate a parity value for the incoming data and compare it to the UPM0 setting. If a mismatch is detected, the PE flag in UCSR0A will be set.

##### UPM31 - Parity Mode Bit 1

`#define UPM31_BIT 5`

`#define UPM31_MASK 32`

This bit enable and set type of parity generation and check. If enabled, the transmitter will automatically generate and send the parity of the transmitted data bits within each frame. The receiver will generate a parity value for the incoming data and compare it to the UPM0 setting. If a mismatch is detected, the PE flag in UCSR0A will be set.

##### UMSEL30 - USART Mode Select

`#define UMSEL30_BIT 6`

`#define UMSEL30_MASK 64`

##### UMSEL31 - USART Mode Select

`#define UMSEL31_BIT 7`

`#define UMSEL31_MASK 128`

### UBRR3H - USART Baud Rate Register High Byte

`sfrb UBRR3H = $135;`

##### UBRR8 - USART Baud Rate Register bit 8

`#define UBRR8_BIT 0`

`#define UBRR8_MASK 1`

##### UBRR9 - USART Baud Rate Register bit 9

`#define UBRR9_BIT 1`

`#define UBRR9_MASK 2`

##### UBRR10 - USART Baud Rate Register bit 10

`#define UBRR10_BIT 2`

`#define UBRR10_MASK 4`

##### UBRR11 - USART Baud Rate Register bit 11

`#define UBRR11_BIT 3`

`#define UBRR11_MASK 8`

### UBRR3L - USART Baud Rate Register Low Byte

`sfrb UBRR3L = $134;`

##### UBRR0 - USART Baud Rate Register bit 0

`#define UBRR0_BIT 0`

`#define UBRR0_MASK 1`

##### UBRR1 - USART Baud Rate Register bit 1

`#define UBRR1_BIT 1`

`#define UBRR1_MASK 2`

##### UBRR2 - USART Baud Rate Register bit 2

`#define UBRR2_BIT 2`

`#define UBRR2_MASK 4`

##### UBRR3 - USART Baud Rate Register bit 3

`#define UBRR3_BIT 3`

`#define UBRR3_MASK 8`

##### UBRR4 - USART Baud Rate Register bit 4

`#define UBRR4_BIT 4`

`#define UBRR4_MASK 16`

##### UBRR5 - USART Baud Rate Register bit 5

`#define UBRR5_BIT 5`

`#define UBRR5_MASK 32`

##### UBRR6 - USART Baud Rate Register bit 6

`#define UBRR6_BIT 6`

`#define UBRR6_MASK 64`

##### UBRR7 - USART Baud Rate Register bit 7

`#define UBRR7_BIT 7`

`#define UBRR7_MASK 128`