Posted on November 17, 2016 at 13:39I'm unable to program the option bytes from user software. In an STM32F103RGT7.
Erase works, program does not.
Code:
// Lock and unlock
FLASH->CR = FLASH_CR_LOCK;
if( FLASH->CR & FLASH_CR_LOCK ){
// Unlock fpec
FLASH->OPTKEYR = 0x45670123;
FLASH->OPTKEYR = 0xCDEF89AB;
}
// Clear flags
FLASH->SR |= FLASH_SR_EOP | FLASH_SR_WRPRTERR | FLASH_SR_PGERR;
// Set option bytes erase
FLASH->CR |= FLASH_CR_OPTER; // Erase
// Start
FLASH->CR |= FLASH_CR_STRT;
__NOP();
while( FLASH->SR & FLASH_SR_BSY );
__NOP();
// Program 1
FLASH->CR = FLASH_CR_LOCK;
if( FLASH->CR & FLASH_CR_LOCK ){
// Unlock fpec
FLASH->KEYR = 0x45670123;
FLASH->KEYR = 0xCDEF89AB;
FLASH->OPTKEYR = 0x45670123;
FLASH->OPTKEYR = 0xCDEF89AB;
}
FLASH->SR |= FLASH_SR_EOP | FLASH_SR_WRPRTERR | FLASH_SR_PGERR;
FLASH->CR |= FLASH_CR_OPTPG; // Write
FLASH->CR |= FLASH_CR_STRT;
p = (__IO uint16_t *)0x1FFFF804;
*p = 0xAA;
// <-- busfault__NOP();
while( FLASH->SR & FLASH_SR_BSY );
__NOP();
As far as I know, I'm following the procedure from the programming manual.
I unlock OPTWRE,
and write the keys to normal key register. Otherwise lock would never clear.
I set OPTPG.
I write a half-word.
I wait for BSY.
But I can't get around the busfault.
What am I doing wrong?
- Using the std libs the code just halts and I get an iwdg reset after 10 seconds.
- I can load the code+options using keil and st link/ulink without problem.
- The ST Link ultity throws an error on writing of option bytes, but they are still programmed.
- Read protection is off.
