I made a PCB board with STM32F407VGT6 (MCU) + STM32F103CBT6 (Debugger). I get the message ''Usb device not recognizable''. Any idea why?

[SSyme.1]

Hi all, I made a PCB board with STM32F407VGT6 (MCU) + STM32F103CBT6 (Debugger). I get the message ''Usb device not recognizable'' when I try to connect it to my computer via USB. I include the pics of my schematic. I followed the schematic of STM32F407G-DISC1

[Tesla DeLorean]

Could swear I posted a response yesterday..

Drive BOOT0 of the F103 high and see if it connects in DFU mode, ie "STM32 in DFU Mode" type reporting in Device Manager.

If you have ST-LINK firmware in DFU form, you could use the DFU tools, or STM32 Cube Programmer to push in that firmware.

[SSyme.1]

Hi all,

I found the solution for loading the ST link firmware to STM32F103CBT6. I downloaded the STM flash loader demo. I connected the Rx Tx pins of a usb to uart cable to the Tx Rx pins (pin 30, pin31) of STM32F103CBT6 and set the Boot0 pin to high (3.3V) as clive1 said. I run the STM flash loader and uploaded the .hex file that can be found in ''Making your own ST-LINK V2 from STM32 Blue-Pill or STM32 Black-Pill'' that contains the firmware.

I can confirm that it works fine.

Thank you!