AnsweredAssumed Answered

Problems with internal bootloader on STM32F405

Question asked by Fischer.Mario.003 on Oct 18, 2016
Latest reply on Oct 18, 2016 by Clive One
We use the internal bootloader of the controller to do the initial firmware programming via USB (DFU). In the last time the we run into trouble with some units - the devices don't properly enumerate on USB (unknown device).

The hardware seems to be ok, since once programmed with our own firmware via SWD, the devices running fine.

I tried to debug the internal bootloader, but didn't come close to a meaningful cause. What I've seen is an endless loop starting nearby 0x1FFF369C, that obviously checks the USART1/3 and the CAN related GPIO Pins. The PLL still uses the HSI clock.

We tied all the CAN and USART related pins according to AN 2606 to a fixed level.

Can somebody give me a hint regarding the cause of this behavior.