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IO Expansion Shields & HATs

Gravity: CH423 I2C 24 Digital IO Expansion Module

SKU: DFR0979

This is an IO expansion module based on the CH423 chip, which can expand 24 digital ports via I2C (8 GPIO ports supporting input, output and interrupt functions, and 16 GPO ports supporting output function only). The module integrates a current drive circuit with a continuous drive current of up to 15mA, enabling it to statically drive 24 LEDs or dynamically drive 128 LEDs. It is suitable for driving LED nixie tubes, dot matrix screens, light arrays, light cubes and other devices.

Front of CH423 I2C IO Expander Board with multiple pins and header connector.-DFRobot product sku:DFR0979 image.

Downloadable Resources

  • Docs
  • Tech Specs
    • 1. Arduino API Functions

    The article explores the main API functions available in Arduino for managing GPIO and GPO pins, including setting pin modes, output levels, reading pin states, and configuring interrupts. It provides detailed descriptions of typedef enums used for pin groups, modes, and interrupt settings, aiming to enhance users' understanding and application of these functions in Arduino projects.
    2. Sample Code for Raspberry Pi

    This article provides step-by-step instructions on using the Raspberry Pi with the CH423 I2C 24 Digital IO Expansion Module, covering hardware and software setup, wiring diagrams, and detailed guidance on running various sample codes to demonstrate different functionalities.
    3. Sample Code for Arduino

    This article provides a comprehensive guide to Arduino sample codes, including detailed hardware and software preparation steps, wiring diagrams, and practical examples such as blink.ino and ioInterrupt.ino. It elaborates on how to configure GPIO and GPO pins to implement LED control, write interrupt handling routines, and complete pin mode configuration with the help of the CH423 library.

    Specification

    Parameter Details
    Power Supply 3.3V-5.5V
    Static Current 1mA
    IO Continuous Drive Current 15mA
    Communication Mode I2C
    I2C Address 0x20-0x3F (This module will occupy the I2C addresses of 0x20-0x3F and can't be used with other I2C devices in the address range.)
    Operating Temperature -20℃-60℃
    Dimension 45x37mm/1.77x1.46"

    Pinout

    dfr0979 Pinout
    dfr0979 Pinout

    Num Name Description
    1 + Power +
    2 - Power -
    3 C I2C Clock Line
    4 D I2C Data Line
    5 GPIO Input and output pin
    6 GPO Output pin

    Pin Mode

    Pin Configurable Mode Default
    GPO Open-drain output and push-pull output Push-pull output high level
    GPIO Input and output Pull-up input

    Note: The pins in the same group can only be set to the same mode at the same time, and the pins in different groups can be set to different modes.

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