stm8flash .bin file for EEPROM write

Question

I am attempting to write values directly to the eeprom space on a stm8 micro controller. I don't want to write a program that does this that I flash onto the chip. But i want to write directly to it. The command to do this is in unix is such:

./stm8flash -c stlinkv2 -p stm8l151f2 -s eeprom -w myfile.bin

My question that I have searched high and low for is how do I make the myfile.bin and what would it look like, is this just C code that I write that assigns the value to the register I pick and then use some compiler that can output to a .bin file? I have done eeprom read/writes within programs but never directly written to eeprom space.The only information I would like to store is information about the product, usage information that can be looked up after. 50 Bytes of data max I would guess.

Answer 1

The easiest thing to do was to first read the file like so:

./stm8flash -c stlinkv2 -p stm8l151f2 -s eeprom -r myfile.bin

Then once that was done I used @thebusybee idea of using a hex editor, I opened the read file (GHex was the editor I used). Using the editor I made my changes and wrote the file using:

./stm8flash -c stlinkv2 -p stm8l151f2 -s eeprom -w myfile.bin

This seems to be working well but the data doesn't match perfectly after a second read, hmm may be a different problem.

Answer 2

I believe that you can only write to EEPROM area properly after unlocking it and verifying if the DATA area is not write protected.

By default, EEPROM is write protected and a specific sequence is required in order to unlock it: two hardware keys have to be written into FLASH_DUKR register. The first time I tried programming EEPROM it didn’t work. The reason was me ignoring the following statement in the reference manual: “before starting programming, the application must verify that the DATA area is not write protected”. I interpreted it as “you shouldn’t write into write-protected areas” while the real meaning was “it takes some time to unlock EEPROM”.

https://lujji.github.io/blog/bare-metal-programming-stm8-part2/

Unfortunately maybe you really need a program just to fill the EEPROM:

//[...]     
#define FLASH_IAPSR *(unsigned char*)0x505F
#define FLASH_DUKR *(unsigned char*)0x5064
#define _MEM_(mem_addr) (*(volatile unsigned char*)(mem_addr))
    
//[...]

void main(){
   //[...]       
   info1 = 127;
   info2 = 32767;
        
   FLASH_DUKR = 0xAE;
   FLASH_DUKR = 0x56;
   while (!(FLASH_IAPSR & (1 << 3)));

   _MEM_(0x4000) = info1;
   while (!(FLASH_IAPSR & (1 << 2)));
   _MEM_(0x4001) = (unsigned char) (info2 & 0xFF);
   while (!(FLASH_IAPSR & (1 << 2)));
   _MEM_(0x4002) = (unsigned char) ((info2 >> 8) & 0xFF);
   while (!(FLASH_IAPSR & (1 << 2)));
        
   FLASH_IAPSR &= ~(1 << 3);
   //[...]
}