How COSMIC compiler allows code to run in RAM

Introduction: For block programming of STM8 MCU Flash, the code must be run in Ram memory. Therefore, the code stored in Flash must be copied to Ram for compilation, linking, and running. Cosmic compiler has two implementation methods: creating segments in STVD project and creating memory segments in link file.

1. Create a segment in the STVD project

1) Set the segment name in the project

'project'->'settings'->'linker'->'category'->'input', as shown below:

Set the segment name to '.FLASH_CODE'. Note that options should also be set to '-ic'. The meaning of ic is moveable code.

2) Write the code stored in the FLASH_CODE segment as shown below

#pragma section(FLASH_CODE) //Put the code in the FLASH_CODE section

void writeFlash(void)

{

……

}

void eraseFlash(void)

{

……

}

#pragma section()//code is placed in the default section

2. Create a memory segment in the link file

1) Define a special memory segment in the link file (*.lkf) and mark it with '-ic', as shown below:

2) Write the code stored in the FLASH_CODE segment as shown below

#pragma section(FLASH_CODE) //Put the code in the FLASH_CODE section

void writeFlash(void)

{

……

}

void eraseFlash(void)

{

……

}

#pragma section()//code is placed in the default section

3. You can check whether the settings of the above two methods are correct in the generated map file, as shown in the following map file:

The part marked 'from' is the code storage part, and the part marked 'initialized' is the execution code part.

4. Calling functions

Before calling these functions, the codes must be copied from flash to Ram. The cosmic compiler uses the built-in function 'int _fctcpy(char name)' to implement this function. Name is the first letter of the defined segment name, such as 'F' in this example.

void main(void)

{

……

_fctcpy('F'); //Copy the Flash code to Ram

……

}