This documentation was generated automatically from the AVR Studio part description file `ATmega8515.pdf`.

## ANALOG COMPARATOR

### ACSR - Analog Comparator Control And Status Register

`sfrb ACSR = $08;`

##### 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.

## USART

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

### UDR - USART I/O Data Register

`sfrb UDR = $0C;`

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

`#define UDR0_BIT 0`

`#define UDR0_MASK 1`

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

`#define UDR1_BIT 1`

`#define UDR1_MASK 2`

##### UDR2 - USART I/O Data Register bit 2

`#define UDR2_BIT 2`

`#define UDR2_MASK 4`

##### UDR3 - USART I/O Data Register bit 3

`#define UDR3_BIT 3`

`#define UDR3_MASK 8`

##### UDR4 - USART I/O Data Register bit 4

`#define UDR4_BIT 4`

`#define UDR4_MASK 16`

##### UDR5 - USART I/O Data Register bit 5

`#define UDR5_BIT 5`

`#define UDR5_MASK 32`

##### UDR6 - USART I/O Data Register bit 6

`#define UDR6_BIT 6`

`#define UDR6_MASK 64`

##### UDR7 - USART I/O Data Register bit 7

`#define UDR7_BIT 7`

`#define UDR7_MASK 128`

### UCSRA - USART Control and Status Register A

`sfrb UCSRA = $0B;`

##### MPCM - Multi-processor Communication Mode

`#define MPCM_BIT 0`

`#define MPCM_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.

##### U2X - Double the USART transmission speed

`#define U2X_BIT 1`

`#define U2X_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.

##### UPE - Parity Error

`#define UPE_BIT 2`

`#define UPE_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.

##### DOR - Data overRun

`#define DOR_BIT 3`

`#define DOR_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.

##### FE - Framing Error

`#define FE_BIT 4`

`#define FE_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.

##### UDRE - USART Data Register Empty

`#define UDRE_BIT 5`

`#define UDRE_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 rea

##### TXC - USART Transmitt Complete

`#define TXC_BIT 6`

`#define TXC_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 bi

##### RXC - USART Receive Complete

`#define RXC_BIT 7`

`#define RXC_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.

### UCSRB - USART Control and Status Register B

`sfrb UCSRB = $0A;`

##### TXB8 - Transmit Data Bit 8

`#define TXB8_BIT 0`

`#define TXB8_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.

##### RXB8 - Receive Data Bit 8

`#define RXB8_BIT 1`

`#define RXB8_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.

##### UCSZ2 - Character Size Bit 2

`#define UCSZ2_BIT 2`

`#define UCSZ2_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.

##### TXEN - Transmitter Enable

`#define TXEN_BIT 3`

`#define TXEN_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.

##### RXEN - Receiver Enable

`#define RXEN_BIT 4`

`#define RXEN_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.

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

`#define UDRIE_BIT 5`

`#define UDRIE_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.

##### TXCIE - TX Complete Interrupt Enable

`#define TXCIE_BIT 6`

`#define TXCIE_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.

##### RXCIE - RX Complete Interrupt Enable

`#define RXCIE_BIT 7`

`#define RXCIE_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.

### UCSRC - USART Control and Status Register C

`sfrb UCSRC = $20;`

##### UCPOL - Clock Polarity

`#define UCPOL_BIT 0`

`#define UCPOL_MASK 1`

Please refer to manual.

##### UCSZ0 - Character Size Bit 0

`#define UCSZ0_BIT 1`

`#define UCSZ0_MASK 2`

##### UCSZ1 - Character Size Bit 1

`#define UCSZ1_BIT 2`

`#define UCSZ1_MASK 4`

##### USBS - Stop Bit Select

`#define USBS_BIT 3`

`#define USBS_MASK 8`

0 = 1 stop bit. 1 = 2 stop bit

##### UPM0 - Parity Mode Bit 0

`#define UPM0_BIT 4`

`#define UPM0_MASK 16`

These bits 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 UCSRA will be set.

##### UPM1 - Parity Mode Bit 1

`#define UPM1_BIT 5`

`#define UPM1_MASK 32`

These bits 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 UCSRA will be set.

##### UMSEL - USART Mode Select

`#define UMSEL_BIT 6`

`#define UMSEL_MASK 64`

0: Asynchronous Operation. 1: Synchronous Operation

##### URSEL - Register Select

`#define URSEL_BIT 7`

`#define URSEL_MASK 128`

This bit selects between accessing the UCSRC or the UBRRH Register. It is read as one when reading UCSRC. The URSEL must be one when writing the UCSRC.

### UBRRH - USART Baud Rate Register High Byte

`sfrb UBRRH = $20;`

##### 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`

##### URSEL - Register Select

`#define URSEL_BIT 7`

`#define URSEL_MASK 128`

### UBRRL - USART Baud Rate Register Low Byte

`sfrb UBRRL = $09;`

##### 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`

## SPI

The Serial Peripheral Interface (SPI) allows high-speed synchronous data transfer between the device and peripheral devices or between several AVR devices. The SPI includes the following features: ? Full-duplex, 3-wire Synchronous Data Transfer ? Master or Slave Operation ? LSB First or MSB First Data Transfer ? Seven Programmable Bit Rates ? End of Transmission Interrupt Flag ? Write Collision Flag Protection ? Wake-up from Idle Mode ? Double Speed (CK/2) Master SPI Mode

### SPDR - SPI Data Register

`sfrb SPDR = $0F;`

##### 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`

### SPSR - SPI Status Register

`sfrb SPSR = $0E;`

##### 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 (see Table 71). 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 ck / 4 or lower. The SPI interface on the ATmega104 is also used for program memory and EEPROM downloading or uploading. See page 253 for serial programming and verification.

##### 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).

### SPCR - SPI Control Register

`sfrb SPCR = $0D;`

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

`#define SPR0_BIT 0`

`#define SPR0_MASK 1`

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

`#define SPR1_BIT 1`

`#define SPR1_MASK 2`

##### 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.

## 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 - Stack pointer bit 12

`#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`

### EMCUCR - Extended MCU Control Register

`sfrb EMCUCR = $36;`

##### ISC2 - Interrupt Sense Control 2

`#define ISC2_BIT 0`

`#define ISC2_MASK 1`

The Asynchronous External Interrupt 2 is activated by the external pin INT2 if the SREG I-bit and the corresponding interrupt mask in GICR are set. If ISC2 is written to zero, a falling edge on INT2 activates the interrupt. If ISC2 is written to one, a rising edge on INT2 activates the interrupt. Edges on INT2 are registered asynchronously. Pulses on INT2 wider than the minimum pulse width given in Table 42 will generate an interrupt. Shorter pulses are not guaranteed to generate an interrupt. When changing the ISC2 bit, an interrupt can occur. Therefore, it is recommended to first disable INT2 by clearing its Interrupt Enable bit in the GICR Register. Then, the ISC2 bit can be changed. Finally, the INT2 interrupt flag should be cleared by writing a logical one to its Interrupt Flag bit (INTF2) in the GIFR Register before the interrupt is re-enabled

##### SRW11 - Wait State Select Bits for Upper Sector, bit 1

`#define SRW11_BIT 1`

`#define SRW11_MASK 2`

##### SRW00 - Wait State Select Bits for Lower Sector, bit 0

`#define SRW00_BIT 2`

`#define SRW00_MASK 4`

##### SRW01 - Wait State Select Bits for Lower Sector, bit 1

`#define SRW01_BIT 3`

`#define SRW01_MASK 8`

##### SRL0 - Wait State Selector Limit bit 0

`#define SRL0_BIT 4`

`#define SRL0_MASK 16`

It is possible to configure different wait states for different external memory addresses. The External Memory address space can be divided in two sectors that have separate wait state bits. The SRL2, SRL1, and SRL0 bits select the splitting of these sectors. By default, the SRL2, SRL1, and SRL0 bits are set to zero and the entire External Memory address space is treated as one sector. When the entire SRAM address space is configured as one sector, the wait states are configured by the SRW11 and SRW10 bits. The manual contains a table on page 28 explaining the bits further

##### SRL1 - Wait State Selector Limit bit 1

`#define SRL1_BIT 5`

`#define SRL1_MASK 32`

It is possible to configure different wait states for different external memory addresses. The External Memory address space can be divided in two sectors that have separate wait state bits. The SRL2, SRL1, and SRL0 bits select the splitting of these sectors. By default, the SRL2, SRL1, and SRL0 bits are set to zero and the entire External Memory address space is treated as one sector. When the entire SRAM address space is configured as one sector, the wait states are configured by the SRW11 and SRW10 bits. The manual contains a table on page 28 explaining the bits further

##### SRL2 - Wait State Selector Limit bit 2

`#define SRL2_BIT 6`

`#define SRL2_MASK 64`

It is possible to configure different wait states for different external memory addresses. The External Memory address space can be divided in two sectors that have separate wait state bits. The SRL2, SRL1, and SRL0 bits select the splitting of these sectors. By default, the SRL2, SRL1, and SRL0 bits are set to zero and the entire External Memory address space is treated as one sector. When the entire SRAM address space is configured as one sector, the wait states are configured by the SRW11 and SRW10 bits. The manual contains a table on page 28 explaining the bits further

##### SM0 - Sleep Mode Select Bit 0

`#define SM0_BIT 7`

`#define SM0_MASK 128`

Please refer to manual for table (Table 16 page 39)

### MCUCR - MCU Control Register

`sfrb MCUCR = $35;`

##### ISC00 - Interrupt Sense Control 0 Bit 0

`#define ISC00_BIT 0`

`#define ISC00_MASK 1`

The External Interrupt 0 is activated by the external pin INT0 if the SREG I-flag and the corresponding interrupt mask are set. The level and edges on the external INT0 pin that activate the interrupt are defined in Table 41 on page 75 in the device handbook. The value on the INT0 pin is sampled before detecting edges. If edge or toggle interrupt is selected, pulses that last longer than one clock period will generate an interrupt. Shorter pulses are not guaranteed to generate an interrupt. If low level interrupt is selected, the low level must be held until the completion of the currently executing instruction to generate an interrupt

##### ISC01 - Interrupt Sense Control 0 Bit 1

`#define ISC01_BIT 1`

`#define ISC01_MASK 2`

The External Interrupt 0 is activated by the external pin INT0 if the SREG I-flag and the corresponding interrupt mask are set. The level and edges on the external INT0 pin that activate the interrupt are defined in Table 41 on page 75 in the device handbook. The value on the INT0 pin is sampled before detecting edges. If edge or toggle interrupt is selected, pulses that last longer than one clock period will generate an interrupt. Shorter pulses are not guaranteed to generate an interrupt. If low level interrupt is selected, the low level must be held until the completion of the currently executing instruction to generate an interrupt

##### ISC10 - Interrupt Sense Control 1 Bit 0

`#define ISC10_BIT 2`

`#define ISC10_MASK 4`

The External Interrupt 1 is activated by the external pin INT1 if the SREG I-bit and the corresponding interrupt mask in the GICR are set. The level and edges on the external INT1 pin that activate the interrupt are defined in Table 40 on page 74 in the manual. The value on the INT1 pin is sampled before detecting edges. If edge or toggle interrupt is selected, pulses that last longer than one clock period will generate an interrupt. Shorter pulses are not guaranteed to generate an interrupt. If low level interrupt is selected, the low level must be held until the completion of the currently executing instruction to generate an interrupt

##### ISC11 - Interrupt Sense Control 1 Bit 1

`#define ISC11_BIT 3`

`#define ISC11_MASK 8`

The External Interrupt 1 is activated by the external pin INT1 if the SREG I-bit and the corresponding interrupt mask in the GICR are set. The level and edges on the external INT1 pin that activate the interrupt are defined in Table 40 on page 74 in the manual. The value on the INT1 pin is sampled before detecting edges. If edge or toggle interrupt is selected, pulses that last longer than one clock period will generate an interrupt. Shorter pulses are not guaranteed to generate an interrupt. If low level interrupt is selected, the low level must be held until the completion of the currently executing instruction to generate an interrupt

##### SM1 - Sleep Mode Select Bit 1

`#define SM1_BIT 4`

`#define SM1_MASK 16`

The description is to long for the tooltip help, please refer to the manual

##### SE - Sleep Enable

`#define SE_BIT 5`

`#define SE_MASK 32`

The SE bit must be written to logic one to make the MCU enter the sleep mode when the SLEEP instruction is executed. To avoid the MCU entering the sleep mode unless it is the programmers purpose, it is recommended to write the Sleep Enable (SE) bit to one just before the execution of the SLEEP instruction and to clear it immediately after waking up.

##### SRW10 - Wait State Select Bits for Upper Sector, bit 0

`#define SRW10_BIT 6`

`#define SRW10_MASK 64`

Please refer to the description found for the SRL bits in the EMCUCR register.

##### SRE - External SRAM/XMEM Enable

`#define SRE_BIT 7`

`#define SRE_MASK 128`

Writing SRE to one enables the External Memory Interface.The pin functions AD7:0, A15:8, ALE, WR, and RD are activated as the alternate pin functions. The SRE bit overrides any pin direction settings in the respective Data Direction Registers. Writing SRE to zero, disables the External Memory Interface and the normal pin and data direction settings are used.

### MCUCSR - MCU Control And Status Register

`sfrb MCUCSR = $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.

##### SM2 - Sleep Mode Select Bit 2

`#define SM2_BIT 5`

`#define SM2_MASK 32`

Please refer to the device manual .

### OSCCAL - Oscillator Calibration Value

`sfrb OSCCAL = $04;`

##### 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`

### SPMCR - Store Program Memory Control Register

`sfrb SPMCR = $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,BLBSET,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 remains 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 effect. Addressing the Flash The Z pointer is used to address the SPM command

##### 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 executed 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

##### 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 the 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 lost

##### 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 automatically 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.

### SFIOR - Special Function IO Register

`sfrb SFIOR = $30;`

##### PSR10 - Prescaler Reset Timer / Counter 1 and Timer / Counter 0

`#define PSR10_BIT 0`

`#define PSR10_MASK 1`

##### PUD - Pull-up Disable

`#define PUD_BIT 2`

`#define PUD_MASK 4`

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).

##### XMM0 - External Memory High Mask Bit 0

`#define XMM0_BIT 3`

`#define XMM0_MASK 8`

When the External Memory is enabled, all Port C pins are used for the high address byte by default. If the full 60KB address space is not required to access the External Memory, some, or all, Port C pins can be released for normal Port Pin function as described in Table 4 on page 29 in the device databook. As described in ?Using all 64KB Locations of External Memory? on page 30, it is possible to use the XMMn bits to access all 64KB locations of the External Memory.

##### XMM1 - External Memory High Mask Bit 1

`#define XMM1_BIT 4`

`#define XMM1_MASK 16`

When the External Memory is enabled, all Port C pins are used for the high address byte by default. If the full 60KB address space is not required to access the External Memory, some, or all, Port C pins can be released for normal Port Pin function as described in Table 4 on page 29 in the device databook. As described in ?Using all 64KB Locations of External Memory? on page 30, it is possible to use the XMMn bits to access all 64KB locations of the External Memory.

##### XMM2 - External Memory High Mask Bit 2

`#define XMM2_BIT 5`

`#define XMM2_MASK 32`

When the External Memory is enabled, all Port C pins are used for the high address byte by default. If the full 60KB address space is not required to access the External Memory, some, or all, Port C pins can be released for normal Port Pin function as described in Table 4 on page 29 in the device databook. As described in ?Using all 64KB Locations of External Memory? on page 30, it is possible to use the XMMn bits to access all 64KB locations of the External Memory.

##### XMBK - External Memory Bus Keeper Enable

`#define XMBK_BIT 6`

`#define XMBK_MASK 64`

## EXTERNAL INTERRUPT

### GICR - General Interrupt Control Register

`sfrb GICR = $3B;`

##### 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 IVSELbit.IVCE is cleared by hardware four cycles after it is written or when IVSEL is written.Setting the IVCE bit will disable interrupts,as explained in the IVSELdescription above.

##### IVSEL - Interrupt Vector Select

`#define IVSEL_BIT 1`

`#define IVSEL_MASK 2`

When the IVSELbit 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 to the start of the boot flash section is determined by the BOOTSZ fuses.Refer to the section ?Boot Loader Support Read While Write self programming ?on page 201 for details.To avoid unintentional changes of interrupt vector tables,a special write procedure must be followed to change the IVSELbit: 1.Set the Interrupt Vector Change Enable (IVCE)bit. 2.Within four cycles,write the desired value to IVSELwhile writing a zero to IVCE. Interrupts will automatically be disabled while this sequence is executed.Interrupts are disabled in the cycle IVCE is set, and they remain disabled until after the instruction following the write to IVSEL.If IVSEL is not written,interrupts remain disabled for four cycles.The I-bit in the Status Register is unaffected by the automatic disabling. Note If Boot Lock bits BLB02 or BLB12 are set,changing the interrupt vector table will change from which part of the program memory interrupts are allowed.Refer to the section ?Boot Loader Support Read While Write self-programmin

##### INT2 - External Interrupt Request 2 Enable

`#define INT2_BIT 5`

`#define INT2_MASK 32`

##### INT0 - External Interrupt Request 0 Enable

`#define INT0_BIT 6`

`#define INT0_MASK 64`

When the INT0 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), the external pin interrupt is enabled. The Interrupt Sense Control0 bits 1/0 (ISC01 and ISC00) in the MCU general Control Register (MCUCR) defines whether the external interrupt is activated on rising or falling edge of the INT0 pin or level sensed. Activity on the pin will cause an interrupt request even if INT0 is configured as an output. The corresponding interrupt of External Interrupt Request 0 is executed from program memory address $001. See also ?External Interrupts.? ? Bits 5..0 - Res: Reserved bits

##### INT1 - External Interrupt Request 1 Enable

`#define INT1_BIT 7`

`#define INT1_MASK 128`

When the INT1 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), the external pin interrupt is enabled. The Interrupt Sense Control1 bits 1/0 (ISC11 and ISC10) in the MCU general Control Register (MCUCR) defines whether the external interrupt is activated on rising or falling edge of the INT1 pin or level sensed. Activity on the pin will cause an interrupt request even if INT1 is configured as an output. The corresponding interrupt of External Interrupt Request 1 is executed from program memory address $002. See also ?External Interrupts?.

### GIFR - General Interrupt Flag Register

`sfrb GIFR = $3A;`

##### INTF2 - External Interrupt Flag 2

`#define INTF2_BIT 5`

`#define INTF2_MASK 32`

When an event on the INT2 pin triggers an interrupt request,INTF2 becomes set (one).If the I bit in SREG and the INT2 bit in GICR are set (one),the MCU will jump to the corresponding interrupt vector.The flag is cleared when the interrupt rou tine is executed.Alternatively,the flag can be cleared by writing a logical one to it.Note that when entering some sleep modes with the INT2 interrupt disabled,the input buffer on this pin will be disabled.This may cause a logic change in inter nal signals which will set the INTF2 flag

##### INTF0 - External Interrupt Flag 0

`#define INTF0_BIT 6`

`#define INTF0_MASK 64`

When an event on the INT0 pin triggers an interrupt request,INTF0 becomes set (one).If the I bit in SREG and the INT0 bit in GICR are set (one),the MCU will jump to the corresponding interrupt vector.The flag is cleared when the interrupt rou tine is executed.Alternatively,the flag can be cleared by writing a logical one to it.This flag is always cleared when INT0 is configured as a level interrupt.

##### INTF1 - External Interrupt Flag 1

`#define INTF1_BIT 7`

`#define INTF1_MASK 128`

When an event on the INT1 pin triggers an interrupt request,INTF1 becomes set (one).If the I bit in SREG and the INT1 bit in GICR 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.This flag is always cleared when INT1 is configured as a level interrupt.

## WATCHDOG

### WDTCR - Watchdog Timer Control Register

`sfrb WDTCR = $21;`

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

`#define WDP0_BIT 0`

`#define WDP0_MASK 1`

The WDP2,WDP1,and WDP0 bits determine the Watchdog Timer prescaling when the Watchdog Timer is enabled.

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

`#define WDP1_BIT 1`

`#define WDP1_MASK 2`

The WDP2,WDP1,and WDP0 bits determine the Watchdog Timer prescaling when the Watchdog Timer is enabled.

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

`#define WDP2_BIT 2`

`#define WDP2_MASK 4`

The WDP2,WDP1,and WDP0 bits determine the Watchdog Timer prescaling when the Watchdog Timer is enabled.

##### 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`

This bit must be set when the WDE bit is written to logic zero.Otherwise,the watchdog will not be disabled.Once written to one,hardware will clear this bit after four clock cycles.Refer to the description of the WDE bit for a watchdog disable procedure.This bit must also be set when changing the prescaler bits.

## TIMER COUNTER 0

### TCCR0 - Timer/Counter 0 Control Register

`sfrb TCCR0 = $33;`

##### CS00 - Clock Select 0

`#define CS00_BIT 0`

`#define CS00_MASK 1`

The three clock select bits select the clock source to be used by the Timer/Counter,

##### CS01 - Clock Select 1

`#define CS01_BIT 1`

`#define CS01_MASK 2`

The three clock select bits select the clock source to be used by the Timer/Counter,

##### CS02 - Clock Select 2

`#define CS02_BIT 2`

`#define CS02_MASK 4`

The three clock select bits select the clock source to be used by the Timer/Counter,

##### WGM01 - Waveform Generation Mode 1

`#define WGM01_BIT 3`

`#define WGM01_MASK 8`

These bits control the counting sequence of the counter, the source for the 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, Clear Timer on Compare match (CTC) mode, and two types of Pulse Width Modulation (PWM) modes. See Table 51 and ?Modes of Operation? on page 80.

##### COM00 - Compare match Output Mode 0

`#define COM00_BIT 4`

`#define COM00_MASK 16`

These bits control the output compare pin (OC0) behavior. If one or both of the COM01:0 bits are set, the OC0 output over-rides the normal port functionality of the I/O pin it is connected to. However, note that the Data Direction Register (DDR) bit corresponding to OC0 pin must be set in order to enable the output driver. When OC0 is connected to the pin, the function of the COM01:0 bits depends on the WGM01:0 bit setting. Table 52 shows the COM01:0 bit functionality when the WGM01:0 bits are set to a normal or CTC mode (non-PWM)

##### COM01 - Compare Match Output Mode 1

`#define COM01_BIT 5`

`#define COM01_MASK 32`

These bits control the output compare pin (OC0) behavior. If one or both of the COM01:0 bits are set, the OC0 output over-rides the normal port functionality of the I/O pin it is connected to. However, note that the Data Direction Register (DDR) bit corresponding to OC0 pin must be set in order to enable the output driver. When OC0 is connected to the pin, the function of the COM01:0 bits depends on the WGM01:0 bit setting. Table 52 shows the COM01:0 bit functionality when the WGM01:0 bits are set to a normal or CTC mode (non-PWM)

##### WGM00 - Waveform Generation Mode 0

`#define WGM00_BIT 6`

`#define WGM00_MASK 64`

These bits control the counting sequence of the counter, the source for the 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, Clear Timer on Compare match (CTC) mode, and two types of Pulse Width Modulation (PWM) modes. See Table 51 and ?Modes of Operation? on page 80.

##### FOC0 - Force Output Compare

`#define FOC0_BIT 7`

`#define FOC0_MASK 128`

The FOC0 bit is only active when the WGM bits specifies a non-PWM mode. However, for ensuring compatibility with future devices, this bit must be set to zero when TCCR0 is written when operating in PWM mode. When writing a logical one to the FOC0 bit, an immediate compare match is forced on the waveform generation unit. The OC0 output is changed accord-ing to its COM01:0 bits setting. Note that the FOC0 bit is implemented as a strobe. Therefore it is the value present in the COM01:0 bits that determines the effect of the forced compare. A FOC0 strobe will not generate any interrupt, nor will it clear the timer in CTC mode using OCR0 as TOP. The FOC0 bit is always read as zero.

### TCNT0 - Timer/Counter 0 Register

`sfrb TCNT0 = $32;`

##### 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`

### OCR0 - Timer/Counter 0 Output Compare Register

`sfrb OCR0 = $31;`

##### OCR0_0

`#define OCR0_0_BIT 0`

`#define OCR0_0_MASK 1`

##### OCR0_1

`#define OCR0_1_BIT 1`

`#define OCR0_1_MASK 2`

##### OCR0_2

`#define OCR0_2_BIT 2`

`#define OCR0_2_MASK 4`

##### OCR0_3

`#define OCR0_3_BIT 3`

`#define OCR0_3_MASK 8`

##### OCR0_4

`#define OCR0_4_BIT 4`

`#define OCR0_4_MASK 16`

##### OCR0_5

`#define OCR0_5_BIT 5`

`#define OCR0_5_MASK 32`

##### OCR0_6

`#define OCR0_6_BIT 6`

`#define OCR0_6_MASK 64`

##### OCR0_7

`#define OCR0_7_BIT 7`

`#define OCR0_7_MASK 128`

### TIMSK - Timer/Counter Interrupt Mask Register

`sfrb TIMSK = $39;`

##### OCIE0 - Timer/Counter0 Output Compare Match Interrupt register

`#define OCIE0_BIT 0`

`#define OCIE0_MASK 1`

When the OCIE0 bit is written to one, and the I-bit in the Status Register is set (one), the Timer/Counter0 Compare Match interrupt is enabled. The corresponding interrupt is executed if a compare match in Timer/Counter0 occurs, i.e. when the OCF0 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

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

`#define TOIE0_BIT 1`

`#define TOIE0_MASK 2`

When the TOIE0 bit is written to one, and the I-bit in the Status Register is set (one), the Timer/Counter0 Overflow interrupt is enabled. The corresponding interrupt is executed if an overflow in Timer/Counter0 occurs, i.e. when the TOV0 bit is set in the Timer/Counter Interrupt Flag Register - TIFR.

### TIFR - Timer/Counter Interrupt Flag register

`sfrb TIFR = $38;`

##### OCF0 - Output Compare Flag 0

`#define OCF0_BIT 0`

`#define OCF0_MASK 1`

The OCF0 bit is set (one) when a compare match occurs between the Timer/Counter0 and the data in OCR0 - Output Compare Register0. OCF0 is cleared by hardware when executing the corresponding interrupt handling vector. Alterna-tively, OCF0 is cleared by writing a logic one to the flag. When the I-bit in SREG, OCIE0 (Timer/Counter0 Compare match Interrupt Enable), and OCF0 are set (one), the Timer/Counter0 Compare match Interrupt is executed.

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

`#define TOV0_BIT 1`

`#define TOV0_MASK 2`

The bit TOV0 is set (one) when an overflow occurs in Timer/Counter0. TOV0 is cleared by hardware when executing the corresponding interrupt handling vector. Alternatively, TOV0 is cleared by writing a logic one to the flag. When the SREG I-bit, TOIE0 (Timer/Counter0 Overflow Interrupt Enable), and TOV0 are set (one), the Timer/Counter0 Overflow interrupt is executed. In PWM mode, this bit is set when Timer/Counter0 changes counting direction at $00.

## TIMER COUNTER 1

The 16-bit Timer/Counter1 can select clock source from CK, prescaled CK, or an external pin. In addition it can be stopped as described in the specification for the Timer/Counter1 Control Registers - TCCR1A and TCCR1B. The different status flags (overflow, compare match and capture event) are found in the Timer/Counter Interrupt Flag Register - TIFR. Control signals are found in the Timer/Counter1 Control Registers - TCCR1A and TCCR1B. The interrupt enable/disable settings for Timer/Counter1 are found in the Timer/Counter Interrupt Mask Register - TIM

### TIMSK - Timer/Counter Interrupt Mask Register

`sfrb TIMSK = $39;`

##### TICIE1 - Timer/Counter1 Input Capture Interrupt Enable

`#define TICIE1_BIT 3`

`#define TICIE1_MASK 8`

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.

##### OCIE1B - Timer/Counter1 Output CompareB Match Interrupt Enable

`#define OCIE1B_BIT 5`

`#define OCIE1B_MASK 32`

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.

##### OCIE1A - Timer/Counter1 Output CompareA Match Interrupt Enable

`#define OCIE1A_BIT 6`

`#define OCIE1A_MASK 64`

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.

##### TOIE1 - Timer/Counter1 Overflow Interrupt Enable

`#define TOIE1_BIT 7`

`#define TOIE1_MASK 128`

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.

### TIFR - Timer/Counter Interrupt Flag register

`sfrb TIFR = $38;`

##### ICF1 - Input Capture Flag 1

`#define ICF1_BIT 3`

`#define ICF1_MASK 8`

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.

##### OCF1B - Output Compare Flag 1B

`#define OCF1B_BIT 5`

`#define OCF1B_MASK 32`

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.

##### OCF1A - Output Compare Flag 1A

`#define OCF1A_BIT 6`

`#define OCF1A_MASK 64`

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.

##### TOV1 - Timer/Counter1 Overflow Flag

`#define TOV1_BIT 7`

`#define TOV1_MASK 128`

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.

### TCCR1A - Timer/Counter1 Control Register A

`sfrb TCCR1A = $2F;`

##### WGM10 - Pulse Width Modulator Select Bit 0

`#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.

##### WGM11 - Pulse Width Modulator Select Bit 1

`#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.

##### FOC1B - Force Output Compare for Channel B

`#define FOC1B_BIT 2`

`#define FOC1B_MASK 4`

The FOC1A/FOC1B bits are only active when the WGM13:0 bits specifies a non-PWM mode.However,for ensuring compatibility with future devices,these bits must be set to zero when TCCR1A is written when operating in a PWM mode.When writing a logical one to the FOC1A/FOC1Bbit,an immediate compare match is forced on the waveform generation unit.The OC1A/OC1B output is changed according to its COM1x1:0 bits setting.Note that the FOC1A/FOC1Bbits are implemented as strobes.Therefore it is the value present in the COM1x1:0 bits that determine the effect of the forced compare. A FOC1A/FOC1B strobe will not generate any interrupt nor will it clear the timer in clear timer on compare match (CTC)mode using OCR1A as TOP. The FOC1A/FOC1Bbits are always read as zero.

##### FOC1A - Force Output Compare for Channel A

`#define FOC1A_BIT 3`

`#define FOC1A_MASK 8`

The FOC1A/FOC1B bits are only active when the WGM13:0 bits specifies a non-PWM mode.However,for ensuring compatibility with future devices,these bits must be set to zero when TCCR1A is written when operating in a PWM mode.When writing a logical one to the FOC1A/FOC1Bbit,an immediate compare match is forced on the waveform generation unit.The OC1A/OC1B output is changed according to its COM1x1:0 bits setting.Note that the FOC1A/FOC1Bbits are implemented as strobes.Therefore it is the value present in the COM1x1:0 bits that determine the effect of the forced compare. A FOC1A/FOC1B strobe will not generate any interrupt nor will it clear the timer in clear timer on compare match (CTC)mode using OCR1A as TOP. The FOC1A/FOC1Bbits are always read as zero.

##### 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.

##### 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.

##### COM1A0 - Compare Ouput 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 pin 1. This is an alternative function to an I/O port and the corresponding direction control bit must be set (one) to control the output pin. The control configuration is shown in Table 9.

##### 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 pin 1. This is an alternative function to an I/O port and the corresponding direction control bit must be set (one) to control the output pin. The control configuration is shown in Table 9.

### TCCR1B - Timer/Counter1 Control Register B

`sfrb TCCR1B = $2E;`

##### CS10 - Clock Select1 bit 0

`#define CS10_BIT 0`

`#define CS10_MASK 1`

##### CS11 - Clock Select1 bit 1

`#define CS11_BIT 1`

`#define CS11_MASK 2`

##### CS12 - Clock Select1 bit 2

`#define CS12_BIT 2`

`#define CS12_MASK 4`

##### WGM12 - Pulse Width Modulator Select Bit 2

`#define WGM12_BIT 3`

`#define WGM12_MASK 8`

Combined with the WGM11:0 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.

##### WGM13 - Pulse Width Modulator Select Bit 3

`#define WGM13_BIT 4`

`#define WGM13_MASK 16`

Combined with the WGM11:0 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.

##### 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.

### TCNT1H - Timer/Counter1 High Byte

`sfrb TCNT1H = $2D;`

##### 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 = $2C;`

##### 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 = $2B;`

##### 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 Output Compare Register A Low Byte

`sfrb OCR1AL = $2A;`

##### OCR1AL0 - Timer/Counter1 Output Compare Register Low Byte Bit 0

`#define OCR1AL0_BIT 0`

`#define OCR1AL0_MASK 1`

##### OCR1AL1 - Timer/Counter1 Output Compare Register Low Byte Bit 1

`#define OCR1AL1_BIT 1`

`#define OCR1AL1_MASK 2`

##### OCR1AL2 - Timer/Counter1 Output Compare Register Low Byte Bit 2

`#define OCR1AL2_BIT 2`

`#define OCR1AL2_MASK 4`

##### OCR1AL3 - Timer/Counter1 Output Compare Register Low Byte Bit 3

`#define OCR1AL3_BIT 3`

`#define OCR1AL3_MASK 8`

##### OCR1AL4 - Timer/Counter1 Output Compare Register Low Byte Bit 4

`#define OCR1AL4_BIT 4`

`#define OCR1AL4_MASK 16`

##### OCR1AL5 - Timer/Counter1 Output Compare Register Low Byte Bit 5

`#define OCR1AL5_BIT 5`

`#define OCR1AL5_MASK 32`

##### OCR1AL6 - Timer/Counter1 Output Compare Register Low Byte Bit 6

`#define OCR1AL6_BIT 6`

`#define OCR1AL6_MASK 64`

##### OCR1AL7 - Timer/Counter1 Output 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 = $29;`

##### 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 = $28;`

##### 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`

### ICR1H - Timer/Counter1 Input Capture Register High Byte

`sfrb ICR1H = $25;`

##### 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 = $24;`

##### 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`

## PORTA

### PORTA - Port A Data Register

`sfrb PORTA = $1B;`

##### 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 = $1A;`

##### 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 = $19;`

##### 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 = $18;`

##### 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 = $17;`

##### 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 = $16;`

##### 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 = $15;`

##### 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 = $14;`

##### 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 = $13;`

##### 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 = $12;`

##### 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 = $11;`

##### 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 = $10;`

##### 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 - Port E Data Register

`sfrb PORTE = $07;`

##### 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`

### DDRE - Port E Data Direction Register

`sfrb DDRE = $06;`

##### 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`

### PINE - Port E Input Pins

`sfrb PINE = $05;`

##### 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`

## 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 High Byte

`sfrb EEARH = $1F;`

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

`#define EEAR8_BIT 0`

`#define EEAR8_MASK 1`

### EEARL - EEPROM Address Register Low Byte

`sfrb EEARL = $1E;`

##### 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 = $1D;`

##### 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 = $1C;`

##### 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

##### EEWE - EEPROM Write Enable

`#define EEWE_BIT 1`

`#define EEWE_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

##### EEMWE - EEPROM Master Write Enable

`#define EEMWE_BIT 2`

`#define EEMWE_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.