Is there a specific manipulation to do to communicate with UART bootloader using a second microcontroller as host ?

[Zephyr S]

Hello,

I am trying to communicate with the UART bootloader (NUCLEO64 F446E) using a second board (NUCLEO32 L432KC).

I am using USART1 (PA_9, PA_10), on which I am trying to send the 0x7F frame to activate UART bootloader (after having activated bootloader Mode using BOOT pins), but I get no answer.

I tried different baudrates even if the AN3155 tells the baudrate is calculated after the reception of the 0x7F frame.

Also, I am using HAL_UART_Receive and Hal_UART_Transmit (with no interrupt) to send and receive data.

I really hope someone could help me.

Thanks in advance 🙂

[waclawek.jan]

Do you have parity set correctly? Note that in STM32, parity bit is counted up to the total number of bits.

JW

[Tesla DeLorean]

You get one-shot after reset to establish the baud rate with the 0x7F pattern.

Show the initialization code. Likely want 9600 Even Parity (will be 9-bit setting on STM32 side) to start with.

Should be able to use HAL_UART_Transmit/Receive to walk the loader along.

Start with simple query commands, checking the response and checksum byte