How to check a PCB is working

Follow the steps below.

1. Jump JP1 points like a photo (paperclip would be fine.)
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2. Wire a LED to the CapsLock points(it has polarity.)
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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.)
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4. And check the install device in Control panel.
If you see the “HIDBoot” in Control panel, the pcb is OK.
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5. In this state, upload the firmware and test it.