Mo & Terry Smedley

H8 I2C/SPI Port Expander

This small external board (about 2" x 3") adds two 8-bit bidirectional ports to the H8 using the I2C (System Support II) or SPI (WizNET GPIO) bus.  The board uses the Microchip MPC23x17 chip which provides bitwise direction control, programmable pull-ups, and interrupt-on-change.  The board has an optional PC-style parallel printer connector (26-pin IDC header) as an option instead of the male pin headers for individual ports "A" and "B" of the MCP chip.  The board was sized to fit within a Hammond 1591XX-BBK ABS box.