Rather than be left on the wrong side of the divide [Stefan S] has come up with his own USB-C version of of an Arduino Pro Micro to avoid ... much slower speed of the ATMEGA32U4 processor, but ...

[John] utilises the Arduino pro micro for its copious analog inputs and USB functionality. A nice feature of this board is that it’s based on the ATMega32U4, which can quickly implement USB ...

which can be used on ATMega328 and ATmega32U4 controllers in addition to the PD Micro, itself.” “Even if you don’t need to integrate other Arduino functionality into your project ...

It's like a shrunken version of the Arduino Leonardo as it features the same ATmega32U4 microcontroller, micro-USB port, and pinouts. It also operates at 5V and requires an external supply of 7 to ...

So the TX and RX leds are driven by a couple of pins on the ATmega32U4 (see a comment on the hardware ... as described in this SparkFun tutorial (actually for the Arduino Pro Micro). Except, I could ...

The Bluefruit LE Micro also offers the ability to program over USB using the Arduino IDE and features an Atmega32u4 chip the that is used as in the Flora or Arduino Leonardo development boards.