PM0068 Reading/programming the STM32F101xF/G and STM32F103xF/G embedded Flash memo-

Doc ID 17100 Rev 2

13/31

Mass Erase

The Mass Erase command can be used to completely erase the user pages of the Flash

memory. The information block is unaffected by this procedure. The following sequence is

recommended:

●

Check that no Flash memory operation is ongoing by checking the BSY bit in the

FLASH_SR register

●

Set the MER bit in the FLASH_CR register

●

Set the STRT bit in the FLASH_CR register

●

Wait for the BSY bit to be reset

●

Read all the pages and verify

Note:

To perform a mass erase on the whole Flash memory, a mass erase must be issued to

bank 1 and bank 2.

Figure 3.

Flash memory Mass Erase procedure

2.3.5

Option byte programming

The option bytes are programmed differently from normal user addresses. The number of

option bytes is limited to 8 (4 for write protection, 1 for read protection, 1 for configuration

and 2 for user data storage). After unlocking the FPEC, the user has to authorize the

programming of the option bytes by writing the same set of KEYS (KEY1 and KEY2) to the

FLASH_OPTKEYR register to set the OPTWRE bit in the FLASH_CR register (refer to

Section 2.3.1 for key values). Then the user has to set the OPTPG bit in the FLASH_CR

register and perform a half-word write operation at the desired Flash address.