Raspberry Pi 3 で 16 個のヘッダー ピンを備えた 2x16 LCD ディスプレイを使用しています。メッセージを表示するには、Adafruit Char LCD ライブラリをインストールして構成しました。そしてそれはうまくいきます。
現在、デフォルトのバックライトの色は黄色なので、青、赤などの他の色に変更したいと考えています。このために、 Adafruit char LCD ライブラリからAdafruit_RGBCharLCD
クラスをインポートしました。Adafruit_RGBCharLCD
class Adafruit_RGBCharLCD(Adafruit_CharLCD):
"""Class to represent and interact with an HD44780 character LCD display with
an RGB backlight."""
def __init__(self, rs, en, d4, d5, d6, d7, cols, lines, red, green, blue,
gpio=GPIO.get_platform_gpio(),
invert_polarity=True,
enable_pwm=False,
pwm=PWM.get_platform_pwm(),
initial_color=(1.0, 1.0, 1.0)):
"""Initialize the LCD with RGB backlight. RS, EN, and D4...D7 parameters
should be the pins connected to the LCD RS, clock enable, and data line
4 through 7 connections. The LCD will be used in its 4-bit mode so these
6 lines are the only ones required to use the LCD. You must also pass in
the number of columns and lines on the LCD.
The red, green, and blue parameters define the pins which are connected
to the appropriate backlight LEDs. The invert_polarity parameter is a
boolean that controls if the LEDs are on with a LOW or HIGH signal. By
default invert_polarity is True, i.e. the backlight LEDs are on with a
low signal. If you want to enable PWM on the backlight LEDs (for finer
control of colors) and the hardware supports PWM on the provided pins,
set enable_pwm to True. Finally you can set an explicit initial backlight
color with the initial_color parameter. The default initial color is
white (all LEDs lit).
You can optionally pass in an explicit GPIO class,
for example if you want to use an MCP230xx GPIO extender. If you don't
pass in an GPIO instance, the default GPIO for the running platform will
be used.
"""
super(Adafruit_RGBCharLCD, self).__init__(rs, en, d4, d5, d6, d7,
cols,
lines,
enable_pwm=enable_pwm,
backlight=None,
invert_polarity=invert_polarity,
gpio=gpio,
pwm=pwm)
self._red = red
self._green = green
self._blue = blue
# Setup backlight pins.
if enable_pwm:
# Determine initial backlight duty cycles.
rdc, gdc, bdc = self._rgb_to_duty_cycle(initial_color)
pwm.start(red, rdc)
pwm.start(green, gdc)
pwm.start(blue, bdc)
else:
gpio.setup(red, GPIO.OUT)
gpio.setup(green, GPIO.OUT)
gpio.setup(blue, GPIO.OUT)
self._gpio.output_pins(self._rgb_to_pins(initial_color))
def _rgb_to_duty_cycle(self, rgb):
# Convert tuple of RGB 0-1 values to tuple of duty cycles (0-100).
red, green, blue = rgb
# Clamp colors between 0.0 and 1.0
red = max(0.0, min(1.0, red))
green = max(0.0, min(1.0, green))
blue = max(0.0, min(1.0, blue))
return (self._pwm_duty_cycle(red),
self._pwm_duty_cycle(green),
self._pwm_duty_cycle(blue))
def _rgb_to_pins(self, rgb):
# Convert tuple of RGB 0-1 values to dict of pin values.
red, green, blue = rgb
return { self._red: self._blpol if red else not self._blpol,
self._green: self._blpol if green else not self._blpol,
self._blue: self._blpol if blue else not self._blpol }
def set_color(self, red, green, blue):
"""Set backlight color to provided red, green, and blue values. If PWM
is enabled then color components can be values from 0.0 to 1.0, otherwise
components should be zero for off and non-zero for on.
"""
if self._pwm_enabled:
# Set duty cycle of PWM pins.
rdc, gdc, bdc = self._rgb_to_duty_cycle((red, green, blue))
self._pwm.set_duty_cycle(self._red, rdc)
self._pwm.set_duty_cycle(self._green, gdc)
self._pwm.set_duty_cycle(self._blue, bdc)
else:
# Set appropriate backlight pins based on polarity and enabled colors.
self._gpio.output_pins({self._red: self._blpol if red else not self._blpol,
self._green: self._blpol if green else not self._blpol,
self._blue: self._blpol if blue else not self._blpol })
def set_backlight(self, backlight):
"""Enable or disable the backlight. If PWM is not enabled (default), a
non-zero backlight value will turn on the backlight and a zero value will
turn it off. If PWM is enabled, backlight can be any value from 0.0 to
1.0, with 1.0 being full intensity backlight. On an RGB display this
function will set the backlight to all white.
"""
self.set_color(backlight, backlight, backlight)
次のように使用しようとしてlcd.set_color() いますが、機能していません。
import time
from Adafruit_CharLCD import Adafruit_RGBCharLCD
# instantiate lcd and specify pins
lcd = Adafruit_RGBCharLCD(rs=26, en=19,
d4=13, d5=6, d6=5, d7=11,
cols=16, lines=2,red=True,Green=True,Blue=True)
lcd.clear()
#setting backlight color as blue
lcd.set_color(0,0,100)
# display text on LCD display \n = new line
lcd.message('2x16 CharLCD\n Raspberry Pi')
私は4ビットノードを使用しており、バックライトピンである最後の2つのピンを次のようにraspberry pi gpioピンに接続しています。
バックライトピン
15 LED+ or A Pin No 2 of GPIO(5v Power)
16 LED- or K Pin No 6 of GPIO(GND)
私はこれが初めてなので、カスタマイズされた色をバックライトとして設定するのを手伝ってください。