UART/Debug access via USB-C port on OSD32MP1-RED design

[Farid Azhar]

We are designing a custom board based on OSD32MP1-RED design. We don’t have access to UART or USB-A on our board, we only use USB-C port on board.
We want to use USB-C port to access UART for debugging during development phase and to function as USB-OTG/Device during normal operation.
The Boot configuration switch (0 0 0) sets the devcie into DFU Flashing mode and does not provide debug access during normal operation.

Is there anyway to configure the Boot pins (BOOT2, BOOT1, BOOT0) to set the USB-C port in Debug/OTG mode during normal operation, after booting from Internal eMMC or MicroSD card.

Thanks for your help.

[Aedan Cullen]

After booting, the common way to get a console over USB is to configure it as a device (a USB “gadget” in Linux) using RNDIS in order to get Ethernet, and then SSH in from there. This is totally an OS-level thing and has nothing to do with boot. For example, OpenSTLinux configures this by default. This is of course convenient for software development after boot, but will not provide you a console earlier in the boot process. I am not aware of a way to get an earlier console over just USB, and I would think it is not very advisable to design a board without access to UART (at least on test pads) for debugging during the boot process.

[Neeraj Dantu]

Farid,

Apart from ssh over RNDIS as Aedan mentioned above, there is no way to get console logs from STM32MP1 via USB while the board is still booting. Alternatively, you can add an extra USB port with an FTDI chip to convert UART4(default console output for STM32MP1) output to USB.

Best,

Neeraj

[Author]

Posts