USB CDC problem

jstefan · ‎2016-03-01

Posted on March 02, 2016 at 00:07

I am using the Stm32CubeL4 to generate a USB device with a CDC class. This is on a custom board. I am not using the USB ID line or VBUS.

It runs, but USBD_CDC_Init() is never called.

On the Windows side, I see an ''unknown device'' with message ''Windows has stopped this device because it has reported problems. (Code 43)''. All driver items are marked as unknown. I tried upgrading the driver it said none found.

I installed stsw_stm32102 the Virtual Com driver but the problem continues.

I suspect there is a low level USB problem that occurs prior to getting the VID/DID, I have not seen the USB become addressed yet.

I have not added any code to send or receive data over the port yet or to handle any events.

I also bumped the heap size to 400 to no avail.

Is there a way to debug the USB interface with Windows and find the cause of the problem?

TIA,

Jan

#o

jstefan · ‎2016-03-04

Posted on March 04, 2016 at 22:02

OK, I got the CDC device working. I had to disable VBUS sensing.

I am not sure what that did, but the Hardware designer of my board did not allow for VBUS to be on a GPIO pin. I thought it odd that I would sense something that is not easy to see.