The Arduino Leonardo can be programmed with the EZB firmware for a variety of capabilities when connected to ARC. Find the firmware below. The tutorial to program the EZB firmware can be found HERE. This firmware works with ARC versions greater or equal to 2019.06.25.00.
* Connection Notes *
Due to an undocumented
bug feature (?), the Arduino Leonardo's USB serial driver requires DTR Enabled to trigger received data events. This can be done by viewing the Connection Config screen (same place you set the baudrate) and checking DTR Enabled checkbox.
In the meantime, download the Ardiuno firmware below. You can program on the Arduino Leonardo. By adding this firmware, you can connect ARC to the Arduino via USB and control the GPIO directly.
Download Arduino Leonardo Firmware: EZ-Genuino_Leonardo.zip
The Digital pins from 0-14 can be used for PWM, servos and digital on/off. The ADC ports are 0-5 for analog input. Digital pin 0 is Uart #0 RX, and digital pin 1 is Uart #0 TX.