The MCP23008 is an alternative to the MCP23017 with 8 GPIOs instead of 16.
This gives it a considerable footprint advantage compared to the MCP23017, in particular the QFN package variant which made it possible for us to squeeze two huge 30A relays onto our 30A Relay HAT.
Our easy installer takes care of the setup process automatically.
sudo wget https://git.plasmadan.com/install.sh sudo sh install.sh
This script will automatically enable I2C, install the required packages and setup the Web GUI.
Alternatively, you can install manually. See our setup guide.
gpio -x mcp23008:100:0x20 read 108
gpio -x mcp23008:100:0x20 mode 108 out
gpio -x mcp23008:100:0x20 write 108 1