Tinyduino I/O line voltage level Does anyone know what the I/O line voltage level is on the Tinyduino?

Tinyduino

I want to run a MAX7219 LED array with it, like this one:

LED Array
Whatever your power supply voltage is. If you run it from 5V you get 5V IO. If you run it from a 3V coin cell you get 3V IO.