Showing results for 
Search instead for 
Did you mean: 

USB CDC on STM32H745 M4 Core is not working.

Associate II

0693W00000Y8QsaQAF.png0693W00000Y8QsGQAV.png0693W00000Y8Qs6QAF.png0693W00000Y8Qs1QAF.pngI am trying following:

1) USB CDC on M4 core

Clock configuration attached

With the help of forum I understand that Descriptor cannot be read from memory location through CM4 as per below thread:

I made following change in usbd_desc.c to avoid hard fault

static void Get_SerialNum(void)


 uint32_t deviceserial0, deviceserial1, deviceserial2;

 deviceserial0 = 0xaa;//*(uint32_t *) DEVICE_ID1;

 deviceserial1 = 0xaa;//*(uint32_t *) DEVICE_ID2;

 deviceserial2 = 0xaa;//*(uint32_t *) DEVICE_ID3;

 deviceserial0 += deviceserial2;

 if (deviceserial0 != 0)


  IntToUnicode(deviceserial0, &USBD_StringSerial[2], 8);

  IntToUnicode(deviceserial1, &USBD_StringSerial[18], 4);



Results are attached.

Pavel A.
Evangelist III

The code10 device ​cannot start is not because of descriptors. Requests for descriptors, strings etc likely were successful.