Mcp23017 - Blinking LED example

This page contains an example for setting up a blinking LED via the I/O extender.

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Connections for this example

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Full example

In this example, we first include the library and create an instance of the board. Next, in the setup() function, we initialize the I2C communication with the I/O expander and set the pin mode for the GPA0 pin (we are using this pin for the LED). Finally, in the loop() function, we change the pin output every second:

// Include the board file
#include "MCP23017-SOLDERED.h"

// Create an instance of the board object
MCP_23017 mcp;

void setup()
{
    // Initialize the board
    mcp.begin();

    // Set the pin to output
    mcp.pinMode(GPA0, OUTPUT);
}

void loop()
{
    // Blink the pin
    mcp.digitalWrite(GPA0, HIGH);
    delay(1000);

    // Turn off the pin
    mcp.digitalWrite(GPA0, LOW);
    delay(1000);
}

mcp.begin()

Initializes the I/O extender via I2C

Returns value: None

mcp.pinMode(uint8_t pin, uint8_t mode)

Controls a single pin's direction

Returns value: None

Function parameters:

Type	Name	Description
uint8_t	pin	pin number
uint8_t	mode	OUTPUT, INPUT or INPUT_PULLUP

mcp.digitalWrite(uint8_t pin, uint8_t state)

Sets the state for a specific pin

Returns value: None

Function parameters:

Type	Name	Description
uint8_t	pin	pin number
uint8_t	state	state in which to put the pin