Bootloader command set

AN3262

18/27

Doc ID 17845 Rev 2

Figure 20.

The host sends the following bytes to the STM32 device:

Byte 1:

0x21

Byte 2:

0xDE

Wait for ACK

Bytes 3 to 6:

Start address (Byte 3 is the MSB and Byte 6 is the LSB)

Byte 7:

Checksum (XOR value of Bytes 3 to 6)

The second and third ACK/NACKs are sent by the device within the same 802.15.4 packet

while the first is sent independently.

Ai14640b

Received bytes =

0x21+0xDE?

Start Go

ROP active

Send ACK byte

Send ACK byte

Receive the start address (4 bytes)

& checksum

Address valid &

checksum

OK?

Send ACK byte

Jump to user application

Send NACK byte

No

Yes

No

Yes

No

End of Go