STM32F411RE NUCLEO Usart Bootloader issue

[OSale.2]

Hi everyone,

I am trying to communicate with default ST UART bootloader on nucleo-F4RE. I have connect the PA9 and PA10 to my second nucleo-board on which I send the 0x7F (9600 baudrate, Even parity,1 stopbit and 8B data (also tried 9B data)). If I check the communication line with logic analyzer I can see that bootloader has returned one time 0x79(ACK byte) and after that immediately 0x1F (NACK byte).

After this, I always get a NACK as return value for every command.

-         I tried difference baudrates  and have studied the ST documentations AN3155 and AN2606.

-         The nucleo board is correct in boot mode by pulling up the Boot0 pin located on CN7 pin 7.

-         I also connect the things on PA2 and PA3. Very strange but with this configuration I get no value return from bootloader.

I really appreciate if someone could help me.

Thanks in advance.      

[Tesla DeLorean]

You get one opportunity out of reset to send the pattern, the pattern isn't received as UART data, but is used to measure time and infer the baud rate.

On the driving STM32 you need 9-bit mode with even parity enabled. This achieves 8E1

I would also suggest using a GPIO in OD mode to drive the reset of the other device, so you can control the interactions cleanly.

Watch for traffic on other pins the loader is looking at, as this will look like a connection attempt, first interface to chirp wins..

Watch for the NUCLEO's VCP