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63 lines
2.0 KiB
Go
63 lines
2.0 KiB
Go
// Copyright 2025 The Periph Authors. All rights reserved.
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// Use of this source code is governed under the Apache License, Version 2.0
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// that can be found in the LICENSE file.
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package hd44780
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import (
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"periph.io/x/conn/v3/gpio"
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"periph.io/x/conn/v3/i2c"
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"periph.io/x/conn/v3/spi"
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"periph.io/x/devices/v3/mcp23xxx"
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"periph.io/x/devices/v3/nxp74hc595"
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)
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const (
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// Name is the LCD pin name, and the integer value is the GPIO
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// number (not physical) of the MCP23008 I2C GPIO Expander.
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d4 = 3
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d5 = 4
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d6 = 5
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d7 = 6
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rsPin = 1
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enablePin = 2
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backlightPin = 7
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)
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// This function returns a display configured to use the Adafruit I2C/SPI LCD Backpack.
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//
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// # Product Information
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//
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// https://www.adafruit.com/product/292
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//
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// The I2C side of this backpack uses an MCP23008 I/O expander. This function
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// creates an MCP23008 device with the required pin configuration. To use this,
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// get an I2C bus, and call this function with the bus, i2c address, number of
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// rows, and columns.
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func NewAdafruitI2CBackpack(bus i2c.Bus, address uint16, rows, cols int) (*HD44780, error) {
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mcp, err := mcp23xxx.NewI2C(bus, mcp23xxx.MCP23008, address)
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if err != nil {
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return nil, err
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}
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gr := *mcp.Group(0, []int{d4, d5, d6, d7, rsPin, enablePin, backlightPin})
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reset, _ := gr.ByOffset(4).(gpio.PinOut)
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enable, _ := gr.ByOffset(5).(gpio.PinOut)
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bl := gr.ByOffset(6).(gpio.PinOut)
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return NewHD44780(gr, &reset, &enable, NewBacklight(bl), rows, cols)
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}
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// This function returns a display configured to use the SPI side of the Adafruit
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// I2c/SPI backpack. The SPI side uses a 74HC595 Serial->Parallel shift register.
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func NewAdafruitSPIBackpack(conn spi.Conn, rows, cols int) (*HD44780, error) {
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chip, err := nxp74hc595.New(conn)
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if err != nil {
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return nil, err
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}
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// The SPI side has the same pins but in reverse order from the I2C side.
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gr, _ := chip.Group(d7, d6, d5, d4)
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rs := &chip.Pins[rsPin]
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e := &chip.Pins[enablePin]
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bl := chip.Pins[backlightPin]
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return NewHD44780(gr, rs, e, NewBacklight(bl), rows, cols)
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}
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