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109 lines
2.4 KiB
Go
109 lines
2.4 KiB
Go
// Copyright 2018 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 ht16k33
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import (
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"errors"
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"periph.io/x/conn/v3/i2c"
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)
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// I2CAddr i2c default address.
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const I2CAddr uint16 = 0x70
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const (
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cmdRAM = 0x00
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cmdKeys = 0x40
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displaySetup = 0x80
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displayOff = 0x00
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displayOn = 0x01
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systemSetup = 0x20
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oscillatorOff = 0x00
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oscillatorOn = 0x01
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cmdBrightness = 0xE0
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)
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// BlinkFrequency display frequency must be a value allowed by the HT16K33.
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type BlinkFrequency byte
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// Blinking frequencies.
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const (
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BlinkOff = 0x00
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Blink2Hz = 0x02
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Blink1Hz = 0x04
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BlinkHalfHz = 0x06
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)
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// Dev is a handler to ht16k33 controller
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type Dev struct {
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dev i2c.Dev
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}
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// NewI2C returns a Dev object that communicates over I2C.
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//
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// To use on the default address, ht16k33.I2CAddr must be passed as argument.
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func NewI2C(bus i2c.Bus, address uint16) (*Dev, error) {
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dev := &Dev{dev: i2c.Dev{Bus: bus, Addr: address}}
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if err := dev.init(); err != nil {
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return nil, err
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}
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return dev, nil
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}
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func (d *Dev) init() error {
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// Turn on the oscillator.
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if _, err := d.dev.Write([]byte{systemSetup | oscillatorOn}); err != nil {
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return err
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}
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// Turn on display
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if _, err := d.dev.Write([]byte{displaySetup | displayOn}); err != nil {
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return err
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}
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// Set no blinking.
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if err := d.SetBlink(BlinkOff); err != nil {
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return err
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}
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// Set display to full brightness.
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return d.SetBrightness(15)
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}
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// SetBlink Blink display at specified frequency.
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func (d *Dev) SetBlink(freq BlinkFrequency) error {
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_, err := d.dev.Write([]byte{displaySetup | displayOn | byte(freq)})
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return err
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}
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// SetBrightness of entire display to specified value.
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//
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// Supports 16 levels, from 0 to 15.
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func (d *Dev) SetBrightness(brightness int) error {
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if brightness < 0 || brightness > 15 {
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return errors.New("ht16k33: brightness must be between 0 and 15")
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}
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_, err := d.dev.Write([]byte{cmdBrightness | byte(brightness)})
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return err
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}
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// WriteColumn set data in a given column.
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func (d *Dev) WriteColumn(column int, data uint16) error {
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_, err := d.dev.Write([]byte{byte(column * 2), byte(data & 0xFF), byte(data >> 8)})
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return err
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}
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// Halt clear the contents of display buffer.
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func (d *Dev) Halt() error {
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for i := 0; i < 4; i++ {
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if err := d.WriteColumn(i, 0); err != nil {
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return err
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}
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}
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return nil
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}
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