STM32L0xx hangs up by reading EEPROM

[Sany]

Hello!

I have these code to store/read data in the EEPROM of my STM32L031K6..

The write function works, the data is saved in flash correctly...

When i want to read the data back, i falling in the HardFault Handler.... :\

This is my Code:

eeprom.h

#define EEPROM_BASE_ADDRESS	0x08080000UL
 
HAL_StatusTypeDef writeEEPROMByte(uint32_t address, uint8_t data)
{
	HAL_StatusTypeDef status;
	uint32_t eepromAddress = address + EEPROM_BASE_ADDRESS;
	HAL_FLASHEx_DATAEEPROM_Unlock();
	status = HAL_FLASHEx_DATAEEPROM_Program(TYPEPROGRAMDATA_BYTE, eepromAddress, data);
	HAL_FLASHEx_DATAEEPROM_Lock();
 
	return status;
}
 
uint8_t readEEPROMByte(uint32_t address)
{
	uint8_t data = 0;
	uint32_t eepromAddress = address + EEPROM_BASE_ADDRESS;
	data = *(__IO uint32_t *)eepromAddress;
	return data;
}

i think, the convertion from uint32_t to uint8_t is wrong, but it works to write the data...

[waclawek.jan]

Where do you have this from?

Why would you need to read an uint32_t, if you return only an uint8_t? In 'L0, an attempt to read a word from a non-word-aligned address leads to fault.

data = *(__IO uint8_t *)eepromAddress;

JW

[Tesla DeLorean · Accepted solution]

Don't think you understand casting properly

data = *(__IO uint8_t *)eepromAddress; // Read byte at address

The CM0 in the STM32L031 will not do unaligned 32-bit reads/writes. Odd addresses will fault, as will those spanning word boundaries.

[Sany]

Hello,

Thanks clive, okay, i understand, i searched a solution to not write words, then i found this code on Github for the STM32L0xx (GitHub stm32EEPROM Library)

Now i see, the code is only tested for the STM32L1xx, i use this code without Problems on my STM32F4, but i forgot the problematic with 32-bit read/write for the CM0, i work first time with this 😉