EEPROM Problem

Hello,

I use HAl_Flash driver on STM32L152RBT6 to read, write and erase internal flash memory(EEPROM).

when i try to write new data to flash, thatbitwise OR with previous value.

(

E.g. at address 0x08007000 pre-save =(int) 5, data =(int) 16 stored-value = (int) 21)

so i need to erase at the specified address before try to store new data on it.

In datasheet clearly explained how can erase

a word (unsigned int ** 4Byte).

Data EEPROM word erase

This operation is used to erase a word in Data EEPROM. To do so:

• Unlock the Data EEPROM and the FLASH_PECR register
• Write a word to a valid address in data EEPROM with the value 0x0000 0000
• This activates an erase phase

code:

uint32_t Address = 0x08007900;
HAL_FLASH_Unlock();
HAL_FLASH_OB_Unlock();
*(uint32_t *)Address = (uint32_t) 0x00;
HAL_FLASH_OB_Lock();
HAL_FLASH_Lock();
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but it doesn't work.

if i set ERASE and PROG bits whole the page(256Byte) will be erased!

SET_BIT(FLASH->PECR, FLASH_PECR_ERASE);
SET_BIT(FLASH->PECR, FLASH_PECR_PROG);�?�?

what can i do for erasing 1 byte or 1 word?

thanks.