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 ...

They were not intended to be normal Arduino I/Os, but were give some commands to turn them on and off, as described in this SparkFun tutorial (actually for the Arduino Pro Micro ... on The Arduino ...