An open source development board around the PIC32MZ2048EFH064-250I/PT microcontroller. All of the PIC32’s I/O ports are exposed to the outside world, with only one permanently reserved for input clock, and one more for an optional secondary input clock for the RTCC. The schematics and all other files are available online.
The serial console is always available as Virtual COM on the USB port.
It is also doubled on the PIC32’s pins 17 (Rx input) and 18 (Tx output). Default protocol is 115200, 8N1.