This 128 GPIO extension board provides 128 channels designed for use on the Raspberry Pi. The board is based around the MCP23s17 16-bit I/O expander from Microchip Technology Inc.

Features:

• Eight MCP23s17 expanders are included on the board allowing you to connect up to 128 digital inputs or outputs to the Raspberry Pi. The 128 GPIO board is powered through the host Raspberry Pi using the GPIO port and extended pins on the GPIO connector allow you to stack the 128 GPIO along with other expansion boards.
• One 20x2 40-pin connector that can connect to the Pi with a 40-pin GPIO cable
• Another 20x2 40-pin connector for extra access to the GPIO pin
• Extra i2c pin and Serial Peripheral Interface (SPI) pin for easy connections to other devices
• Each 23s17 address can be rearranged to your needs by changing the A0, A1, A2 address selector pins
• 128 LEDs that show the status of the GPIO

Technical specifications:

• 23s17 U2, U3, U4, U5, U6, U7, U8, U9 with GPIO Port A and B
• Output of each GPIO to 2x10 pin:
• Bank B (1-10) GPIO (0, 1, 2, 3, 4, 5, 6, 7, GND, INTB)
• Bank A (1-10) GPIO (0, 1, 2, 3, 4, 5, 6, 7, GND, INTA)
•  23s17 Datasheet

Demo software:

• 23s17-cs0.py     n23s17-cs0.py
• 23s17-8port-s-v103.py     23s17-8port-s-v104.py