{"title":"Adafruit MCP23017 I2C GPIO Expander Breakout","handle":"adafruit-mcp23017-i2c-gpio-expander-breakout","url":"/products/adafruit-mcp23017-i2c-gpio-expander-breakout","description":"The Adafruit MCP23017 I2C GPIO Expander Breakout adds 16 extra GPIO pins to any microcontroller or microcomputer over I2C. Each pin can be configured as a digital output (driving up to 25 mA — perfect for LEDs) or as an input with optional internal pull-up resistors.\n\nWith three configurable address pins, you can connect up to 8 boards on a single I2C bus for a total of 128 GPIO. Two configurable interrupt (IRQ) pins let you monitor input changes without polling the bus. The MCP23017 runs on both 3.3V and 5V power and logic, making it compatible with virtually any development board.\n\nKey Features\n\n\n16 GPIO Pins – Each configurable as input (with optional pull-up) or output (up to 25 mA per pin)\n\nI2C Interface – Simple two-wire communication with 3 address pins for up to 8 devices per bus\n\nDual Interrupt Pins – Configurable IRQ outputs eliminate the need for bus polling\n\n3.3V and 5V Compatible – Works with any logic level without additional shifting\n\nSTEMMA QT / Qwiic Ports – Solderless I2C daisy-chaining on both sides of the board\n\nMatching Ground Pads – Convenient ground connections alongside each GPIO pin\n\nBreadboard Friendly – Includes header strips for breadboard prototyping\n\n\nIdeal For\n\nProjects requiring more GPIO than your microcontroller provides\nLED matrix or button matrix control\nInput expansion for keypads, switches, and sensors\nDaisy-chaining multiple expanders for large-scale I/O\n\n\nPackage Contents\n\n1× Adafruit MCP23017 I2C GPIO Expander Breakout (with STEMMA QT / Qwiic connectors)\n2× Header pin strips\n\n\n\nTip: Connect buttons directly by wiring one side to a GPIO pin (set as input with pull-up) and the other to a ground pad — no extra resistors needed.\n\n\nResources\n\nArduino Library (GitHub)\nCircuitPython Guide (Adafruit Learn)\nWhat is STEMMA QT? (Adafruit Learn Guide)\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":2472,"title":"Default Title","sku":"AF-5346","price":12.67,"on_sale":false,"in_stock":true,"available_quantity":101,"option1":"Default Title"}]}