Controlling MAX7219 8x8 Matrix LED with Raspberry Pi

昔々　Arduinoで試して死蔵してたMAX7219 と8x8 Matrix LEDを
Raspberry Piに繋げてみました。

3.3Vで動きましたね

配線
MAX7219 Pin Name Remarks RPi Pin RPi Function
1 VCC +5V Power 　　　　　1 3.3V
2 GND Ground         　　　　6 GND
3 DIN Data In        　　　　19 GPIO 10 (MOSI)
4 CS Chip Select    　　　　24 GPIO 8 (SPI CE0)
5 CLK Clock        　　　　　23 GPIO 11 (SPI CLK)

circuitPythonでの動作確認です。

# apt install python3-pip
# pip3 install --upgrade setuptools
# pip3 install RPI.GPIO
# pip3 install adafruit-blinka

# apt install python3-pil
# pip3 install adafruit-circuitpython-max7219

sample code get
# git clone https://github.com/adafruit/Adafruit_CircuitPython_max7219.git

[max7219_heike.py]

#!/usr/bin/env python3

import time

##from board import TX, RX, A1

from board import CE0

import board

import busio

import digitalio

from adafruit_max7219 import matrices

#-----------------------------

from PIL import Image

from PIL import ImageDraw

from PIL import ImageFont

def horizontal_scroll(image, padding=True):

        image_list = list()

        width = image.size[0]

        # Scroll into the blank image.

        if padding:

            for x in range(8):

                section = image.crop((0, 0, x, 8))

                display_section = create_blank_image()

                display_section.paste(section, (8 - x, 0, 8, 8))

                image_list.append(display_section)

        #Scroll across the input image.

        for x in range(8, width + 1):

            section = image.crop((x - 8, 0, x, 8))

            display_section = create_blank_image()

            display_section.paste(section, (0, 0, 8, 8))

            image_list.append(display_section)

        #Scroll out, leaving the blank image.

        if padding:

            for x in range(width - 7, width + 1):

                section = image.crop((x, 0, width, 8))

                display_section = create_blank_image()

                display_section.paste(section, (0, 0, 7 - (x - (width - 7)), 8))

                image_list.append(display_section)

        #Return the list of images created

        return image_list

def create_blank_image():

      return Image.new("RGB", (8, 8))

def image_gen(img):

        """Set buffer to value of Python Imaging Library image.  The image should

        be in 1 bit mode and a size equal to the display size."""

        imwidth, imheight = img.size

        # Grab all the pixels from the image, faster than getpixel.

        pixels = img.convert('1').load()

        # Iterate through the pixels

        for x in range(8):       # yes this double loop is slow,

            for y in range(8):  #  but these displays are small!

                matrix.pixel(x, y, pixels[(x, y)])

            matrix.show()

text = "ぎおんしょうじゃのかねのこえ しょぎょうむじょうのひびきあり さらそうじゅのはなのいろ じょう しゃひっすいのことわりをあらわす おごれるひともひさしからず ただはるのよのゆめのごとし たけきもの もついにはほろびぬ ひとえにかぜのまえのちりにおなじ"

text_len = len(text)

image = Image.new('1', (text_len*8, 8))

draw  = ImageDraw.Draw(image)

font  = ImageFont.truetype("/home/pi/font/misakifont/misaki_gothic.ttf", 8, encoding='unic')

draw.text((0,0), text, font=font, fill=255)

##mosi = TX

##clk = RX

##cs = digitalio.DigitalInOut(A1)

cs = digitalio.DigitalInOut(CE0)

##spi = busio.SPI(clk, MOSI=mosi)

spi = busio.SPI(board.SCLK, board.MOSI, board.MISO)

matrix = matrices.Matrix8x8(spi, cs)

matrix.fill(False)

#image_gen(matrix, image)

image_list = horizontal_scroll(image)

max_images = len(image_list)

while True:

    for i in range(0, max_images):

         image_gen(image_list[i])

#         time.sleep(0.5)