Solved
STM32 Internal Flash erase but not 0xFF or 0x00
Hello. I am working with internal Flash memory on STM32F407, I have 4 functions as described below:
void FLASH_save_CP_serial(uint32_t serial_number) {
taskENTER_CRITICAL();
uint32_t write_test = 12345;
FLASH_EraseInitTypeDef EraseInitStruct;
uint32_t page_err;
EraseInitStruct.TypeErase = FLASH_TYPEERASE_SECTORS;
EraseInitStruct.Sector = FLASH_SECTOR_11;
EraseInitStruct.NbSectors = 1;
EraseInitStruct.VoltageRange = FLASH_VOLTAGE_RANGE_3;
HAL_FLASH_Unlock();
FLASH_WaitForLastOperation(2000);
HAL_FLASHEx_Erase(&EraseInitStruct, &page_err);
FLASH_WaitForLastOperation(2000);
if(HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, 0x80E0000, write_test) == HAL_OK){
DEBUG_PRINT("write successfull \n");
}
else{
DEBUG_PRINT("failed to write to EEPROM\n");
}
FLASH_WaitForLastOperation(2000);
HAL_FLASH_Lock();
FLASH_WaitForLastOperation(2000);
taskEXIT_CRITICAL();
}
/*FLASH_read_CP_serial(uint32_t* RxBuf)
* Reads back 4 byte value from the 0x80E0000 address and saves the value to RxBuf
*
*
*/
void FLASH_read_CP_serial(uint32_t* RxBuf){
taskENTER_CRITICAL();
RxBuf = (uint32_t *)0x80E0000;
DEBUG_PRINT("%u\n", *RxBuf);
taskEXIT_CRITICAL();
}
/*
* FLASH_check_if_CP_serial_empty()
* Check if there is any value saved to 0x80E0000 address
* Returns 1 if no value is currently written
* Returns 0 if some value has been written
*/
bool FLASH_check_if_CP_serial_empty(){
const volatile uint32_t *EEP=(const volatile uint32_t *)((uint32_t)0x80E0000);
if((EEP[0] == 0xFFFFFFFF) || (EEP[1] == 0xFFFFFFFF))
{
return true; // settings not written.
}
return false;
}
/*
* FLASH_erase_cp()
* Erase the whole sector (0x80E0000 - 0x80FFFFF)
*
*
*/
void FLASH_erase_cp(){
FLASH_EraseInitTypeDef EraseInitStruct;
uint32_t page_err;
EraseInitStruct.TypeErase = FLASH_TYPEERASE_SECTORS;
EraseInitStruct.Sector = FLASH_SECTOR_11;
EraseInitStruct.NbSectors = 1;
EraseInitStruct.VoltageRange = FLASH_VOLTAGE_RANGE_3;
HAL_FLASH_Unlock();
FLASH_WaitForLastOperation(2000);
HAL_FLASHEx_Erase(&EraseInitStruct, &page_err);
FLASH_WaitForLastOperation(2000);
}In my program, I would like to detect if any value has been written to my desired location of the Flash memory (0x80E0000).
I expect to do that using function:
FLASH_check_if_CP_serial_empty()When I erase the whole sector with
void FLASH_erase_cp()and then read the current value in the Flash address using:
FLASH_read_CP_serial(uint32_t* RxBuf)4294967295 is returned even though I have just erase the whole sector.
I am expecting to see 0xFFFFFFFF or 0x00000000. Is there any problem in my code? Why erasing does not write FF or 00 to the Flash memory?