The Raspberry Pi is an incredible single board computer - and one of the best parts is this GPIO connector! 40 digital kindness pins that you can turn to control LEDs, sensors, buttons, radios, screens - just about any device you can imagine. This Adafruit GPIO Expander Bonnet will give you even more digital delicacy - 16 additional digital input/output pins for all your desires. The outputs are grouped into two 16-pin connectors that have a corresponding ground pin. You can set each pin to be a digital output (high or low) or as an input, with an internal pull-up if you wish!

Simply place the cap on your Pi, the circuits connect to the SDA/SCL I2C pins for control. The MCP23017 chip converts our Python commands into pin instructions.

When used as an output, each pin can provide up to 20mA (tight current) - so you can drive the LEDs directly. The data sheet recommends keeping the total current consumption for the entire chip below 125mA. By default, we configure the expander chip for 5V logic (I2C is level shifted, so it is 3V logic). We have done this so that you can drive white, blue or green LEDs that sometimes are not very satisfied with the 3.3V logic. Or, you can cut/weld a jumper to change it to 3.3V logic.

When used as an input, you can configure a pull-up resistor so that buttons and switches do not need additional resistors - just wire the pin on one side and ground it on the other! There are interrupt possibilities on the chip, and two IRQ pins (INTA and INTB) on which you can solder a wire, if you want to have a quick way to know if one of the GPIOs has changed.

By welding the address selection jumpers, you can change the address from 0x20 to 0x27. So, if you wanted, you could have up to 8 covers for a total of 128 GPIOs.

Delivered in the form of a cap assembled and tested with a 2x20 low connector. We provide 2 sets of 16-pin IDC plugs, you can solder them or not for a thin installation. Follow our guide to use our CircuitPython library with Python 3 for quick and easy installation and configuration, you will be up and running in less than 5 minutes.

Product dimensions: 65.0mm x 30.6mm x 30.6mm x 5.6mm / 2.6" x 1.2" x 0.2" x 0.2

Product weight : 10.4g / 0.4oz

Documentation

Adafruit GPIO Expander Bonnet for Raspberry Pi