The Raspberry Pi has a limited number of GPIO pins. The MCP23017 adds 16 more. The MCP23017 uses only 2 pins (SDA and SCL) for I2C communication, saving GPIO pins on the Raspberry Pi. I'm sure I had ...

We’ve gotten used to the GPIO-available functions of Raspberry Pi computers remaining largely the same over the years, which is why it might have flown a little bit under the radar: the Raspberry Pi 4 ...

3 green SDA I2C: Serial data input / output TTL 5V compatible 4 yellow SCL I2C: Serial clock input TTL 5V compatible 5 NC Do not connect Ground (Pins 2 and 5 are connected internally) 6 NC Do not ...