USB MSC is being detecting only after watchdog triggers

[hhuynh222]

Hi all,

Im hoping to get some insight here. I went through the dcd_stm32_fsdev.c on how to configure my microcontroller. I have STM32G4 microcontroller and I am having issue with detecting USB connection. I used CubeMX to generate the code where I make the following configurations:

• set CRS_SYNC to USB_FS
• set USB to device FS.
• no middleware selected
• there was only one interrupt i could find in the generated code that i redirected the handler to point to TinyUSB handler.

Observation:
It seems that it detects USB connection only after watchdog has been triggered. When I remove the watchdog, it doesn't seem to see it and gets stuck. I found a post from 4 years ago and my settings matched to what they have to no effect. Can anyone suggest what else i can try?

[hhuynh222]

this is what I am seeing from the logs:

USBD init on controller 1, speed = Full
sizeof(usbd_device_t) = 52
sizeof(dcd_event_t) = 12
sizeof(tu_fifo_t) = 12
sizeof(tu_edpt_stream_t) = 20
MSC init

USBD init on controller 1, speed = Full
sizeof(usbd_device_t) = 52
sizeof(dcd_event_t) = 12
sizeof(tu_fifo_t) = 12
sizeof(tu_edpt_stream_t) = 20
MSC init

USBD Bus Reset : Full Speed

USBD init on controller 1, speed = Full
sizeof(usbd_device_t) = 52
sizeof(dcd_event_t) = 12
sizeof(tu_fifo_t) = 12
sizeof(tu_edpt_stream_t) = 20
MSC init

USBD Bus Reset : Full Speed

USBD Setup Received 80 06 00 01 00 00 40 00
Get Descriptor Device
Queue EP 80 with 18 bytes ...
USBD Xfer Complete on EP 80 with 18 bytes
Queue EP 00 with 0 bytes ...
USBD Xfer Complete on EP 00 with 0 bytes
USBD Bus Reset : Full Speed

USBD Setup Received 00 05 21 00 00 00 00 00
Set Address
USBD Xfer Complete on EP 80 with 0 bytes

USBD Setup Received 80 06 00 01 00 00 12 00
Get Descriptor Device
Queue EP 80 with 18 bytes ...
USBD Xfer Complete on EP 80 with 18 bytes
Queue EP 00 with 0 bytes ...
USBD Xfer Complete on EP 00 with 0 bytes

USBD Setup Received 80 06 00 02 00 00 FF 00
Get Descriptor Configuration[0]
Queue EP 80 with 32 bytes ...
USBD Xfer Complete on EP 80 with 32 bytes
Queue EP 00 with 0 bytes ...
USBD Xfer Complete on EP 00 with 0 bytes

As I mentioned previously, this kind of works due to watchdog in place. When programming is running and USB is inserted, watchdog is triggered and afterwards USB is detected. Without the watchdog it goes into infinite loop when I try to connect USB

[hhuynh222]

I found the issue. I was relying too much on Cubemx. It didn't generate all the interrupts that I needed. I had to manually insert them. Everything works now.