**Details** This Tibbit is based on the MCP23008 8-bit port expander IC from Microchip. Refer to Microchip datasheet for operation details. This C1 device requires the Tibbit #00-3 to be installed in the neighboring "M" Tibbit socket. To simplify wiring, Tibbit #41 is supplied with a 200mm WAS-P044 cable. **Sample project** The use of this Tibbit is illustrated by a Tibbo BASIC test project. Yo can find it here: [https://github.com/tibbotech/CA-Test-Tibbit-41](https://github.com/tibbotech/CA-Test-Tibbit-41).