Stm32mp157 som usb dfu

Products & Technology ODYSSEY Serials
#1

Hello,

I fail to enter USB DFU mode on the SoM. I would assume that if all BOOT bits are low it should enter USB DFU. Am I missing something. I have a board where I have wires straight from PA11 and PA12 of the SOM DF40 connector (7.70 pin 4 och 2) straight out to a USB connector. I do not see anything happening as far as DFU.

If I place the SoM on the SeeeD devkit I would assume that the USB DFU popup on the USB-c connector if the J9 switch is set to BOOT.

Doing this on the official DK2 devkit I get the USB DFU.

What am I missing?

Best regards

#2

To answer my own question. The DFU is present on USB2.

Edit:

USB1? Isn’t that a host port, the upper port on the Odyssey board?

Sorry, my mistake, the lower port, USB2.

#3

USB1? Isn’t that a host port, the upper port on the Odyssey board?

#4

For anyone interested, the VBUS line on the Odyssey STM32MP157 isn’t powered until Linux or U-Boot pulls up the associated power GPIO. So you can use DFU just using a regular type A to type A cable and it should work fine. However, once the port is powered you risk reverse current flow through the STMPS2252 chip on the board. Not good! So my suggestion is to strip support for that port from the device trees if present. Either that or cut the VBUS line in your cable. Eugh.