MCP23008T-E/ML: 8-Bit I/O Expander with I2C Interface from Microchip

In the realm of embedded systems and IoT design, managing a sufficient number of General-Purpose Input/Output (GPIO) pins is a common challenge. Microchip Technology's MCP23008T-E/ML provides an elegant and efficient solution to this problem. This integrated circuit is an 8-bit I/O expander that communicates via the ubiquitous I2C serial interface, enabling a microcontroller to control up to eight additional I/O ports using only two I/O pins.

Housed in a compact and space-saving 20-lead QFN (ML) package, the MCP23008 is ideal for space-constrained applications. Its core functionality revolves around providing bidirectional I/O expansion. Each of its eight ports can be individually configured as either an input or an output through the I/O Direction register. This flexibility allows designers to interface with a wide array of peripherals, including sensors, buttons, LEDs, and relays.

A key advantage of the MCP23008 is its simplicity of integration. The I2C interface supports standard (100 kHz) and fast (400 kHz) mode operations, allowing for communication with a vast majority of modern microcontrollers. The device features three hardware address pins, enabling users to connect up to eight of these expanders on the same I2C bus, theoretically providing access to 64 additional GPIOs from a single bus. This daisy-chaining capability is crucial for complex systems requiring extensive input and output control.

Beyond basic I/O control, the chip incorporates several features that enhance system robustness and reduce microcontroller overhead. These include programmable pull-up resistors on each input pin, eliminating the need for external discrete resistors. Furthermore, it offers an interrupt output pin that can be configured to trigger on pin state change events. This allows the host microcontroller to operate in a low-power sleep mode until an input change occurs, significantly optimizing power consumption in battery-powered devices.

The MCP23008T-E/ML is characterized for industrial temperature ranges (-40°C to +85°C), making it suitable for a broad spectrum of applications, from consumer electronics to industrial automation and automotive systems. Its combination of a simple serial interface, high integration, and flexible features makes it an indispensable component for system designers looking to extend the capabilities of their microcontroller without moving to a larger, more expensive package.

ICGOOODFIND: The MCP23008T-E/ML is a highly versatile and efficient I2C-based I/O expander. Its minimal pin count requirement, configurable interrupt output, and ability to add significant GPIO capacity make it an outstanding choice for solving connectivity limitations in modern embedded designs.

Keywords: I2C Interface, GPIO Expander, Bidirectional I/O, Interrupt Output, Programmable Pull-ups.