This listing includes five MCP23017E/SO devices. The MCP23017 is a 16bit I/O expander with I2C interface that provides 16 bidirectional I/O lines across two 8bit ports (PORTA and PORTB). It allows you to extend microcontroller I/O without adding pins on the main controller. Key benefits Increase I/O capacity: add 16 configurable I/O pins to your system to handle more sensors, switches, or indicators without expanding the microcontroller. I2C based expansion: works on a shared I2C bus with other devices, allowing multiple expanders on the same bus by using three hardware address pins (A0, A1, A2). Flexible I/O control: each port can be configured individually as input or output; supports internal pull up on input pins. Output stability: uses output latches to prevent glitches when changing port directions or states. Interrupt capability: provides INTA and INTB outputs to signal changes on input pins for responsive, eventdriven designs. Compact packaging: available in a 28pin surfacemount SOIC package (MCP23017E/SO), suitable for compact boards. Compatible voltage range: operates from 1.8V to 5.5V, enabling use with both 3.3V and 5V systems. I2C performance: supports standardmode and fastmode I2C operation, enabling reliable communication on common microcontroller platforms. Key attributes Functionality: 16 I/O pins organized as PORTA and PORTB (two 8bit ports); I/O direction, pullup control, and I/O state are programmable via registers; includes GPIO and OLAT outputs. Compatibility: I2C interface compatible with typical microcontrollers and development platforms; supports multiple devices on the same bus with distinct addresses (A0A2). Size and packaging: 28pin SOIC package (MCP23017E/SO); compact surfacemount format for integration into small boards. Voltage and timing: operates at 1.8V to 5.5V; I2C bus speeds include standardmode (100 kHz) and fastmode (400 kHz) operation. Performance and features: two 8bit I/O ports with independent direction control; programmable pullups per pin; interrupt outputs for change notification; registers include IODIRA, IODIRB, GPIOA, GPIOB, OLAT, GPPU, INTF, INSTAT, IOCON and related config options. Use cases Microcontroller I/O expansion: easily add 16 digital I/O lines to an Arduino, Raspberry Pi, ESP32, or other microcontroller projects without sacrificing main controller pins. Indicator and LED control: drive multiple LEDs or LED indicators across a panel, including simple LED matrices, with reliable output buffering and optional pullups for inputs. Button matrices and sensor arrays: read multiple pushbuttons or sensors with minimal MCU pins; leverage interrupt outputs to respond quickly to user input or event changes. Applications Hobbyist and professional projects requiring scalable I/O expansion on a single I2C bus. Embedded control panels, home automation nodes, or sensor arrays needing additional digital inputs and outputs. Prototyping and development environments where rapid I/O expansion is advantageous without redesigning main control circuitry. Notes Each MCP23017E/SO device provides 16 generalpurpose I/O lines across PORTA and PORTB, with 3 hardware address pins enabling up to 8 devices on one I2C bus. This listing includes five identical MCP23017E/SO devices in a 28pin SOIC package.