No Response From Bootloader over USART

RPowe.9.306 · ‎2020-07-21

My employers have made a custom board based on STM32WB55. I have developed some software but need to program this to flash. I have access to USART1 and BOOT0 pin. (I also have access to SWD, SWCLK, JTDI, JTDO). I thought that pulling BOOT0 high would enable me to talk to the bootloader over the USART but I get no response. I have tried the ST programmer and have also tried talking from my C# app by sending 0x7F at various baudrates to see if I at least get an ACK. Any help please.

HRadt.1 · ‎2020-07-21

Maybe you fell for the same trap that I did: The Bootloader only works with Pins PA9/PA10 as TX/RX pins. Not with PB6/PB7.

RPowe.9.306 · ‎2020-07-23

Thanks.

This is the sort of gotcha that should have a warning in big bold letters but never does!

Actually have Rx on PA9 and Tx on PB6

HRadt.1 · ‎2020-07-23

It defininitely should ... especially since without bootloader access, a lot of the steps needed for production are way more complicated (depending on your usecase).