HAL USB_CoreReset times out on the CM4 core of a Nucleo-H745zi-q

[WLear]

Attempting to get USB CDC running on the CM4 core of a stock Nucleo-H745zi-q board. USB_CoreReset() times out waiting for a soft reset. Any help would be greatly appreciated.

Timeout is in stm32h7xx_ll_usb.c, lines 1456-1469:

/* Core Soft Reset */
 count = 0U;
 USBx->GRSTCTL |= USB_OTG_GRSTCTL_CSRST;
 
 do
 {
 count++;
 
 if (count > 200000U)
 {
 return HAL_TIMEOUT;
 }
 } while ((USBx->GRSTCTL & USB_OTG_GRSTCTL_CSRST) == USB_OTG_GRSTCTL_CSRST);

USB clock is RC48

Project built with CubeMX V6.6.1, CubeIDE V1.10.1, Firmware FW_H7 V1.10.0

 I moved the USB from the CM4 core to the CM7, and this issue does not occur.

[Walid ZRELLI]

Hello @WLear​ ,

You can refer to the following example provided under the H7 Firmware Package which uses both cores CM4 and CM7:

Path: Projects\STM32H747I-EVAL\Applications\USB_Device\HID-CM4_MSC-CM7

I hope this helps.

BeST Regards,

Walid

[WLear]

Thankyou. Unfortunately, this example exhibits the same issue as my code. See the response from @SofLit for the root cause.

[mƎALLEm]

Hello,

If you look at usbd_desc.c/line 337: Get_SerialNum() function does access the system memory. Unfortunately, CM4 doesn't have access to this region.

So to use the device ID as a serial number, you have to read it by CM7, save it in the RAM which will be available later-on for CM4. 

You can test it by -in Get_SerialNum()- replacing:

deviceserial0 = *(uint32_t *) DEVICE_ID1;

deviceserial1 = *(uint32_t *) DEVICE_ID2;

deviceserial2 = *(uint32_t *) DEVICE_ID3;

by:

deviceserial0 = 0xABCDEF12;

deviceserial1 = 0x12345678;

deviceserial2 = 0x12A3D459;

[WLear]

Yes, This test patch does allow the USB init function to return without timing out. I trust this bug will be fixed in the next H7 firmware release.

[RichH81]

I just ran into this bug, CubeIDE version 1.14.1, STM32H755, USB running on the CM4. Stepping through initialization I don't see it hitting the Get_SerialNum function before attempting the CoreReset. It times out waiting on USB_OTG_GRSTCTL_CSRST. I changed the Get_SerialNum function as described above but I'm still getting the time out. Were you able to implement a workaround to allow the CM4 to run USB? Thanks!