Two MCP23017 I2C I/O Expander Modules

Add digital input and output connections to a microcontroller project with a pair of MCP23017 I/O-expander modules.

✅ Connect more digital signals - Sixteen I/O channels per expander provide additional points for compatible project inputs and outputs.

✅ Use the controller's I2C bus - A serial interface links the expander to the host without a separate host pin for every signal.

✅ Plan two circuit sections - The two-module selection provides expanders for separate boards or parts of the same build.

Make room for the project's extra signals

Buttons, indicators and other digital connections can quickly use up the pins available on a controller. An I/O expander provides another set of connections while the host communicates with it through the supported bus.

Design the connections around the module's supply, logic levels and output-current limits. These are signal-expansion boards, so higher-current loads need the appropriate separate driver circuitry rather than direct connection.

Technical details

• Device: MCP23017
• Function: 16-bit digital I/O expansion
• Host interface: I2C
• Quantity: two modules
• Check module voltage and signal-current limits before integration

Give your controller project room for more digital connections.