hi guys, i am working of stm32f103c8t6 to create a virtual com port. but every time i plug in the device "A request for the USB device descriptor failed." issue arises. can someone guide me to get this working............

[waclawek.jan]

Try if DFU bootloader works, to confirm there's no hardware issue.

Debug as any other code - observe the USB registers' content; hook on the USB interrupt and observe whether USB reset has been handled, whether setup packets arrive and are handled properly; observe the USB bus using a bus analyzer or LA/oscilloscope capable of decoding USB protocol, etc.

JW

[NKoot.1]

Thank you waclawek.jan,

I am a beginner with stm's. I will try everything as you suggested and let you know the results...

[NKoot.1]

Can I get a sample code to refer if possible...

[NKoot.1]

i was not able to find dfu bootloader in stm32f10xxx series. i checked in the 'an2606 document' table 3