Generic Arduino Micro Pro turning RX/TX led on with LOW


I have a generic Micro Pro 3.3v.

I write only "digitalWrite(17, LOW)", the RX led turns on. If I put in HIGH, it turns off. Other generics types of board, like a Nano and MEGA that I have, that doesn't happen. Any idea what it is?


Pin 17 controls the RX led on Pro Micro.

Those other boards have a separate usb-serial chip. One of the pins of that chip controls the RX led on those boards.

Pro Micro has usb built into the MCU chip itself, so must use one of its own pins to control the RX led.

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