Hello,
I am writing a programm for a raspi cm4 to flash a programm on an STM32 using the UART bootloader. The raspi parses some hex file that I want to flash and sends data packets to the bootloader using the 0x31 write command.
Here is what I have achieved until now:
- Successfully enable the bootloader and initiate uart communication
- Erase the user memory (mass erase command)
- Use the write command and receive an ACK back
When I run the complete programm, no error is returned and no error/nack is returned. I can affirm that the bootloader answers all my requests without exception with an ACK because I monitor the bus with a logic analizer. However, when I compare the memory to the initial hex file I am trying to flash, there are some differences.
Everything is identical up to this part of the hex file:
:04EBD0009E467047A6
:10EBD800000000000000000000000000000000002D
:10EBE8000000000001000000020000000300000017
Starting from the address 0x0801EBD8, none of the bytes I send to the bootloader are written (everything is 0xFF) into the memory, even though it returns acknowledges to all my request.
My guess is that everything before EBD0 is 16bytes-aligned, but because of the 4 bytes gap between EBD4 and EBD8, all the addresses I'm writing at from this point are only 8bytes-aligned. These addresses are apparently invalid and the documentation for the uart bootloader indeed specifies: "No error is
returned when the start address is invalid."
I compiled myself the programm on STMCUBEIDE to obtain the hex file. I am surprised that it would provide a file where the addresses are not compatible with my MCU. Furthermore, the documention for the bootloader tells me that the word alignement required for my MCU is 8 bytes:
All of this is very confusing to me. My idea of a solution would be to manually pad the memory from EBD4 to EBD8 with 0xFF to keep the size of my packets a multiple of 16 but this doesn't sound right.
Any suggestions or remarks regarding my reasoning?
Thank you for your help.
