STM32L152RET6 bootloader via huart3

mt1 · ‎2024-09-16

Is it possible to use UART3 as the bootloader interface on this chip?

I’m able to communicate with UART3 (so the hardware connection seems fine), but I’m unsure about the baud rate—does the bootloader autodetect it, or is it fixed? The bootloader works fine over USB, and I can successfully enter bootloader mode. However, when I disconnect the USB and attempt to use UART3, I can’t establish a connection.

I understand that not all chips support all UARTs for bootloading, and in the documentation, I see references to UART1, UART2, and some mention of other UART interfaces. Could you clarify if UART3 is supported for bootloader flashing on this chip?

STTwo-32 · ‎2024-09-16

Hello @mt1 and welcome to the ST Community.

The Bootloader is not available throw the STM32L152RET6. It is only available on the USART1 and USART2 only according to the AN2606:

For the Usartx Line, it refers to x=1 or 2. Systick timer should be enables to automatically detect the serial baud
rate from the host for USART1/2 bootloader

Best Regards.

STTwo-32

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Peter BENSCH · ‎2024-09-16

... and the line USARTx refers to the previous lines with the supported interfaces, i.e. USART1/2.

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