USB problem on STM32F411CEU6

[uraich]

Hi,
Today I flashed MicroPython on my STM32F411CEU6 board. I tried dfu mode but did not see any dfu device using dfu-util. I managed to flash it with stlink. When connecting it with an USB to serial adapter on PA9, PA10 everything works fine. However, I cannot use the USB type C connector to talk to the board.

stm32error.png (60.6 KiB) Viewed 4559 times

I am using Ubuntu 20.04.
Has anybody seen and solved this problem?

[jsa13]

There is no DFU boot loader on the board default you have to install it first with your st-link, but there are not much space left on the flash, so I do not know if it is a good idea to use it. I have tested the board once and didn't  have any problems with the USB.

[dhylands]

The STM32F4 series has a built in DFU bootloader - no need to flash one.

In order to use USB, you should have your PLL frequencies setup so that the system clock is a multiple of 48 MHz, so you should run it at 96 MHz rather than 100 MHz.

[shaoziyang]

If crystal‘s load capacitance is not match, it will takes a long time before PLL frequencies stable, exceed DFU bootloader detect time.

[uraich]

I am using the board specs from https://github.com/mcauser/WEACT_F411CEU6 which say that the board is configured to run at 96 MHz.

stm32.png (24.06 KiB) Viewed 4462 times

Having a look at the issues chapter on this repository it seems that I am not the only one having the problem.

[dhylands]

What host device are you using?

Have you tried using a hub between your host and the board?

The fact that the REPL works fine on PA9 and PA10 suggests that the clock is being setup properly, otherwise your baud rate wouldn't work out. I would also double check your power/ground connections from the USB-C connector. There are multiples of power and ground and D+/D- which all need to be connected together on your board.

Also try flipping the USB-C cable over. They're supposed to be symmetrical, but I've seen weirder things.

[uraich]

Finally I found the culprit: It was the type C USB cable giving problems. I received another cable for test and with that new cable everything works as expected.