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devices/hd44780/af_i2c_backpack.go

47 lines
1.4 KiB
Go

// Copyright 2025 The Periph Authors. All rights reserved.
// Use of this source code is governed under the Apache License, Version 2.0
// that can be found in the LICENSE file.
package hd44780
import (
"periph.io/x/conn/v3/gpio"
"periph.io/x/conn/v3/i2c"
"periph.io/x/devices/v3/mcp23xxx"
)
const (
// Name is the LCD pin name, and the integer value is the GPIO
// number (not physical) of the MCP23008 I2C GPIO Expander.
d4 = 3
d5 = 4
d6 = 5
d7 = 6
rsPin = 1
enablePin = 2
backlightPin = 7
)
// This function returns a display configured to use the Adafruit I2C/SPI LCD Backpack.
//
// # Product Information
//
// https://www.adafruit.com/product/292
//
// The I2C side of this backpack uses an MCP23008 I/O expander. This function
// creates an MCP23008 device with the required pin configuration. To use this,
// get an I2C bus, and call this function with the bus, i2c address, number of
// rows, and columns.
func NewAdafruitI2CBackpack(bus i2c.Bus, address uint16, rows, cols int) (*HD44780, error) {
mcp, err := mcp23xxx.NewI2C(bus, mcp23xxx.MCP23008, address)
if err != nil {
return nil, err
}
gr := *mcp.Group(0, []int{d4, d5, d6, d7, rsPin, enablePin, backlightPin})
grPins := gr.Pins()
reset := grPins[4].(gpio.PinOut)
enable := grPins[5].(gpio.PinOut)
bl := grPins[6].(gpio.PinOut)
return NewHD44780(gr, &reset, &enable, &bl, rows, cols)
}