Microchip MCP23X17 16-bit I/O Expander, SPI Interface, PDIP-28

The Microchip MCP23X17 is a versatile 16-bit input/output port expander designed to add GPIO capabilities to microcontroller systems via a high-speed Serial Peripheral Interface (SPI). It features multiple 8-bit configuration registers for flexible control over input, output, and polarity selection for each pin, making it an essential component for expanding digital I/O in space-constrained designs.

A system master configures each I/O pin as an input or output by writing to the I/O Direction registers (IODIRA/B). Data for each port is held in corresponding input or output registers, and the polarity of the input data can be easily inverted using the dedicated polarity inversion register, simplifying interface logic.

Key Features & Performance

• Cascadable Design: Up to eight devices can be connected on a single bus, allowing for expansion of up to 128 additional I/O pins.
• High Drive Capability: Each I/O pin offers a robust 25 mA sink/source current, enabling it to drive LEDs and other peripherals directly.
• High-Speed Interface: Supports SPI clock speeds of up to 10 MHz for fast data transfer.
• Advanced Interrupt Control: Features configurable interrupt output pins that can be triggered by pin state changes, reducing the need for continuous polling by the host microcontroller.
• Low Power Operation: Includes an external reset input and boasts a very low standby current of just 1 µA (maximum), making it suitable for power-sensitive applications.

Housed in a standard PDIP-28 package, it is ideal for prototyping and breadboarding. Its wide operating voltage range from 1.8V to 5.5V and extended temperature tolerance from -40°C to +125°C ensure reliable performance in diverse and demanding environments, from industrial automation to embedded development projects.