How to check a PCB is working

Follow the steps below.

1. Jump JP1 points like a photo (paperclip would be fine.)

2. Wire a LED to the CapsLock points(it has polarity.)

3. Connect USB cable to a PC. If then, it will enter Bootloader mode and the LED will flash.
(If you see the LED flashing, your PCB itself is OK.)

4. And check the install device in Control panel.
If you see the “HIDBoot” in Control panel, the pcb is OK.

5. In this state, upload the firmware and test it.