mcp23xxx

Documentation

Overview

Package mcp23xxx provides driver for the MCP23 family of IO extenders

Datasheet

https://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf

Example

package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/gpio"
	"periph.io/x/periph/conn/i2c/i2creg"
	"periph.io/x/periph/experimental/devices/mcp23xxx"
	"periph.io/x/periph/host"
)

func main() {
	// Make sure periph is initialized.
	if _, err := host.Init(); err != nil {
		log.Fatal(err)
	}

	// Open default I²C bus.
	bus, err := i2creg.Open("")
	if err != nil {
		log.Fatalf("failed to open I²C: %v", err)
	}
	defer bus.Close()

	// Create a new I2C IO extender
	extender, err := mcp23xxx.NewI2C(bus, mcp23xxx.MCP23017, 0x20)
	if err != nil {
		log.Fatalln(err)
	}

	for _, port := range extender.Pins {
		for _, pin := range port {
			err = pin.In(gpio.Float, gpio.NoEdge)
			if err != nil {
				log.Fatalln(err)
			}
			level := pin.Read()
			fmt.Printf("%s\t%s\n", pin.Name(), level.String())
		}
	}

	if err != nil {
		log.Fatalln(err)
	}
}

Index

• type Dev
  • func NewI2C(b i2c.Bus, variant Variant, addr uint16) (*Dev, error)
  • func NewSPI(b spi.Conn, variant Variant) (*Dev, error)
  • func (d *Dev) Close() error
• type Pin
• type Variant

Examples

• Package

Types

type Dev

type Dev struct {
	// Pins provide access to extender pins.
	Pins [][]Pin
}

Dev his a handle for a configured MCP23xxx device.

func NewI2C

func NewI2C(b i2c.Bus, variant Variant, addr uint16) (*Dev, error)

NewI2C initializes an IO extender through I2C connection.

func NewSPI

func NewSPI(b spi.Conn, variant Variant) (*Dev, error)

NewSPI initializes an IO extender through I2C connection.

func (*Dev) Close

func (d *Dev) Close() error

Close removes any registration to the device.

type Pin

type Pin interface {
	gpio.PinIO
	// SetPolarityInverted if set to true, GPIO register bit reflects the same logic state of the input pin.
	SetPolarityInverted(p bool) error
	// IsPolarityInverted returns true if the value of the input pin reflects inverted logic state.
	IsPolarityInverted() (bool, error)
}

Pin extends gpio.PinIO interface with features supported by MCP23xxx devices.

type Variant

type Variant string

Variant is the type denoting a specific variant of the family.

const (
	// MCP23008 8-bit I2C extender. Datasheet: https://www.microchip.com/wwwproducts/en/MCP23008
	MCP23008 Variant = "MCP23008"

	// MCP23S08 8-bit SPI extender. Datasheet: https://www.microchip.com/wwwproducts/en/MCP23S08
	MCP23S08 Variant = "MCP23S08"

	// MCP23009 8-bit I2C extender. Datasheet: https://www.microchip.com/wwwproducts/en/MCP23009
	MCP23009 Variant = "MCP23009"

	// MCP23S09 8-bit SPI extender. Datasheet: https://www.microchip.com/wwwproducts/en/MCP23S09
	MCP23S09 Variant = "MCP23S09"

	// MCP23016 16-bit I2C extender. Datasheet: https://www.microchip.com/wwwproducts/en/MCP23016
	MCP23016 Variant = "MCP23016"

	// MCP23017 8-bit I2C extender. Datasheet: https://www.microchip.com/wwwproducts/en/MCP23017
	MCP23017 Variant = "MCP23017"

	// MCP23S17 8-bit SPI extender. Datasheet: https://www.microchip.com/wwwproducts/en/MCP23S17
	MCP23S17 Variant = "MCP23S17"

	// MCP23018 8-bit I2C extender. Datasheet: https://www.microchip.com/wwwproducts/en/MCP23018
	MCP23018 Variant = "MCP23018"

	// MCP23S18 8-bit SPI extender. Datasheet: https://www.microchip.com/wwwproducts/en/MCP23S18
	MCP23S18 Variant = "MCP23S18"
)