Memory map files are tree structured descriptions of the target memory map.
Memory map files are used by the compiler to ensure correct placement of program
sections. Memory map files are used by the debugger so that it knows which memory
addresses are valid on the target and which program sections to load. You can
also use the memory files to direct the debugger to display memory mapped peripherals.
Usually you don't need to modify memory map files—they will be set up
for the particular targets that CrossStudio supports but it is useful to view
them with the memory map editor.
You can open memory map files using File > Open and selecting the
XML file that contains the memory map or alternatively using the View Memory
Map option on the context menu of the Project Explorer.
The memory map editor provides a tree structured view of the memory space of
a target. The memory map consists of a set of different node types that are
arranged in a hierarchy. These nodes have properties that can be modified using
the properties window when the node is selected. These properties and the placement
of nodes within the memory map are used as input to the program building process
so that the linker knows where sections should be placed. Additionally the debugger
uses the information in memory map files to enable register display and memory
display.
The memory map editor supports the following node types:
- Root
- The top most node of the memory map.
- Memory Segment
- A range of addresses that represents a memory region in the target.
- Program Section
- Represents a program section of your application.
- Register Group
- Represents an area of memory that contains a group of related
registers.
- Register
- Represents a memory mapped register.
- Bit Field
- Part of a memory mapped register.
The following statements hold regarding the creation and movement of nodes
within a memory
- Memory segments can be within the Root segment.
- Program sections must be within a memory segment.
- Register groups can be within the Root or within a memory segment.
- Registers can be within memory segments or register groups.
- Bit Fields can be within registers.
All nodes have mandatory and optional properties associated with them. All
nodes have a mandatory Name property. This name should be unique within the
memory map.
Memory segment and register group properties
- Start Address
- A hexadecimal number stating where the memory begins (lowest address).
- Start Address Symbol
- The name of a linker symbol to generate that has the value of the
Start Address.
- Size
- A hexadecimal number that defines the size in bytes of
the memory segment.
- Size Symbol
- The name of a linker symbol to generate that has the value of the
Size.
- Access Type
- Specifies if the memory segment is read only or read/write.
Program section properties
- Start Address
- An optional hexadecimal value that is the absolute load
position of the section. If this isn't set then the relative placement of
the program section within the memory segment will determine the load position
of the section.
- Size
- An optional decimal value that is the size in bytes of
the program section.
- Load
- Specifies whether or not the section should be loaded by
the debugger.
- Alignment
- An optional decimal value that specifies the alignment
requirements of the section.
- Section To Run In
- An optional name of another program section that this program
section will be copied to.
- Input Section Names
- The optional names of the files that will be placed into
this section.
Register properties
- Start Address
- A hexadecimal value specifying where the register is placed.
- Start Address Symbol
- The name of a linker symbol to generate that has the value of the
Start Address.
- Register Type
- Optional, a C type specifying how you want the register to be displayed.
The defaults to the word length of the target processor.
- Endian
- Optional, specifies the byte order of a multibyte register. This defaults
to the byte order of the target processor.
Bitfield properties
- Bit Offset
- A decimal value that is the starting bit position of the
bit field. Bit 0 is the first bit position.
- Bit Length
- A decimal value that defines the number of bits in the
field.
The editor has many of the attributes of the text editor and the same key-bindings
for example cut, copy and paste are all accessible from the Edit menu.
In addition to the standard editor capabilities the memory map editor supports
the movement up and down of nodes within a hierarchy. This enables the sequencing
of program sections to be achieved.