The TS-8100 includes a 2x8 0.1" pitch header with 8 DIO, I2C, and SPI. Most DIO on this header are rated for 3.3V and are not tolerant of 5V IO. The only exception is SPI_MOSI which is 5V tolerant. The DIO on this baseboard can be accessed by manipulating the TS-8100 Register Map.
All DIO pins on this header have 3.9K pull up resistors.