AN3155 datasheet(21/37 Pages) STMICROELECTRONICS

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AN3155

Bootloader command set

The host sends the bytes to the STM32 as follows:

3.7

Erase Memory command

The Erase Memory command allows the host to erase Flash memory pages. When the

bootloader receives the Erase Memory command, it transmits the ACK byte to the host.

After the transmission of the ACK byte, the bootloader receives one byte (number of pages

to be erased), the Flash memory page codes and a checksum byte; if the checksum is

correct then bootloader erases the memory and sends an ACK byte to the host, otherwise it

sends a NACK byte to the host and the command is aborted.

Erase Memory command specifications:

the bootloader receives one byte that contains N, the number of pages to be erased –

N = 255 is reserved for global erase requests. For 0

≤ N ≤ 254, N + 1 pages are erased.

the bootloader receives (N + 1) bytes, each byte containing a page number

Note:

No error is returned when performing erase operations on write protected sectors.

Byte 1:

0x31

Byte 2:

0xCE

Wait for ACK

Byte 3 to byte 6:start address

byte 3: MSB

byte 6: LSB

Byte 7:

Checksum: XOR (Byte3, Byte4, Byte5, Byte6)

Wait for ACK

Byte 8:

Number of bytes to be received (0 < N

≤ 255)

N +1 data bytes:(Max 256 bytes)

Checksum byte: XOR (N, N+1 data bytes)

AN3155 Datenblatt(PDF) 21 Page - STMicroelectronics