Implementation of a STM32 in transparent mode to flash another UART-connected STM32. What UART configurations and timing should be setting to implement this feature in STM32 in transparent mode?

[vincent]

I have one Master STM32 connected over UART to a Linux MPU and also connected over another UART to a Slave STM32.

My purpose is to set the Slave STM32 in bootloader and flash from the MPU the application in the Slave STM32, the Master STM32 is in the middle and responsible to transfer data between the MPU and the Slave STM32.

During my test, I can see that :

• The Master STM32 sets the Slave STM32 in bootloader as expected
• The Master STM32 transmits to the Slave STM32 0x7F coming from MPU
• The Slave STM32 responds a ACK
• The Master STM32 transmits to the Slave STM32 0x7F 2 times without response from the Master Slave
• The Master STM32 transmits to the Slave STM32 a "Get Version & Read Protection Status command".
• The Slave STM32 responds a NACK

On both UART of the Master STM32 connected to MPU and to the Slave STM32, I have the following configuration :

• Word Length = 9 Bits
• Stop Bit = One Stop bit
• Parity = Evenparity
• BaudRate = 115200 baud
• Hardware flow control disabled

[KK.4]

@vincent​  Were you able to achieve this functionality. I was trying to achieve the same thing, any help on this would be highly appreciated.