Texas Instruments MSC1210 manual Advanced Topics 15-11

Flash Memory as Data Memory

unsigned char i;

//synchronize baud rate autobaud();

//Set the pointer to the beginning of the page to modify pFlashPage = (char xdata * ) PAGE_START;

//before writing the flash, we have to initialize

//the usec and msec SFRs because the flash programming

//routines rely on these SFRs

USEC = 12−1; // assume a 12 MHz clock

MSEC = 12000−1;

while(1)

{

//copy the page from FLASH to RAM for(i=0;i<PAGE_SIZE;i++)

Buffer[i] = *pFlashPage++;

//increment the counter Buffer[0] += 1;

//now erase the page

page_erase(PAGE_START, 0xff, DATA_FLASH); Result = 0;

//and write the modified contents back into flash for(i=0;i<PAGE_SIZE;i++)

Result = write_flash_chk (PAGE_START+i, Buffer[i],

DATA_FLASH);

// re−read the counter

pFlashPage = (char xdata *) PAGE_START;

printf(”flash write returned %d, Reset counter is now %d, press any key\n”, (int) Result, (int)(*pFlashPage));

while(RI==0); RI = 0;

}

}

Note:

Your program must use the boot ROM routines, such as write_flash_chk, in order to modify flash data memory, if your program is itself executing from flash memory. That is because the instructions are being fetched from flash memory, and writing to flash memory simultaneously causes a conflict that results in undesired program execution. The boot ROM routines must be used to modify flash memory whenever your program itself resides on-chip in flash memory.

Advanced Topics 15-11