MAX7219 8x8 LED矩陣顯示

模組介紹

當你走在街上，你看到的各種LED霓虹燈看板只是N x N個點矩陣。現在讓我們看一下8*8點矩陣的工作原理。點矩陣的內部結構和外觀如下。8x8點陣由64個發光二極體組成，每個發光二極體位於行與列的交點上。當對應的行為高電位，列為低電位時，對應的發光二極體為亮。

我們嘗試在實驗中顯示一個心形的圖形, 所以我們將紅色部分設置為高電位, 另一部分設置為低電位，LED動態掃描後會顯示一個心形的圖形。因為這是動態掃描，我們需要注意兩個點的重影和閃爍。對人眼的殘留影響為25Hz。但通常掃頻為50Hz效果較好，因此每一列的延遲時間不能超過1000/50/8=2.5ms。如果我們將延遲設置為2ms，效果會更好。 將介紹如何使用單顆 MAX7219 驅動 8x8 矩陣式顯示器。當使用 MAX7219 的原始資料模式時 (若不熟悉 MAX7219 運作模式，可參考之前的教學範例)，矩陣顯示器的每個欄位可對應到一個 Digit 暫存器，也就是說，第 0 欄對應到 Digit 0、第 1 欄對應到 Digit 1... 以此類推。而矩陣的每一列則對應到七段顯示器中的不同筆劃，從顯示器最上方開始，第 0 列對應到 Digit 暫存器資料的第 0 個位 (LSB)、第 1 列對應到 Digit 暫存器的第 1 個位... 依序下去，直到第 7 列對應到 Digit 暫存器的 MSB (第 7 位)。以實際範例說明，例如要在矩陣顯示器上顯示數位 "7" 的圖像：

根據圖上的位元資訊，可知 "7" 的位圖樣可被表示為：

const byte bitmap_7[] =

{

// define the dot pattern from column 0 ~ column 7

B00000000, B00000000, B01100001, B00010001, B00001001, B00000111, B00000000, B00000000

};

而這些資訊就是後續會送進 Digit 暫存器作為顯示用的原始資料。

電路圖

程式列表

Python - MAX7219.py

# Reference:

# Micropython driver for the max7219 with Matrix8x8 display

# https://micropython-max7219.readthedocs.io/en/latest/matrix.html

# https://github.com/adafruit/micropython-adafruit-max7219

REG_NO_OP = 0x00

REG_DIGIT_BASE = 0x01

REG_DIGIT0 = 0x01

REG_DIGIT1 = 0x02

REG_DIGIT2 = 0x03

REG_DIGIT3 = 0x04

REG_DIGIT4 = 0x05

REG_DIGIT5 = 0x06

REG_DIGIT6 = 0x07

REG_DIGIT7 = 0x08

REG_DECODE_MODE = 0x09 #Decode-Mode Register

# 0x00: No decode for digits 7¡V0

# 0x01: Code B decode for digit 0,No decode for digits 7¡V1

# 0x0F: Code B decode for digits 3¡V0, No decode for digits 7¡V4

# 0xFF: Code B decode for digits 7¡V0,

REG_INTENSITY = 0x0A #Intensity Register Format

# MAX7219 MAX7221

# 0x00: 1/16 1/32

# 0x01: 3/32 2/16

# 0x02: 5/32 3/16

# 0x03: 7/32 4/16

# 0x04: 9/32 5/16

# 0x05: 11/32 6/16

# 0x06: 13/32 7/16

# 0x07: 15/32 8/16

# 0x08: 17/32 9/16

# 0x09: 19/32 10/16

# 0x0A: 21/32 11/16

# 0x0B: 23/32 12/16

# 0x0C: 25/32 13/16

# 0x0D: 27/32 14/16

# 0x0E: 29/32 15/16

# 0x0F: 15/16 31/32

REG_SCAN_LIMIT = 0x0B #Scan-Limit Register Format

# 0x00: Display digits 0 X X X X X X X

# 0x01: Display digits 0 1 X X X X X X

# 0x02: Display digits 0 1 2 X X X X X

# 0x03: Display digits 0 1 2 3 X X X X

# 0x04: Display digits 0 1 2 3 4 X X X

# 0x05: Display digits 0 1 2 3 4 5 X X

# 0x06: Display digits 0 1 2 3 4 5 6 X

# 0x07: Display digits 0 1 2 3 4 5 6 7

REG_SHUTDOWN = 0x0C #Shutdown Register Format

# 0x00 Shutdown Mode

# 0x01 Normal Operation

REG_DISPLAY_TEST = 0x0F #Display-Test Register Format

# 0x00 Normal Operation

# 0x01 Display Test Mode

NUM_DIGITS = 8

class Matrix8x8:

def __init__(self, spi, intensity=7):

self.spi = spi

self.buffer = bytearray(NUM_DIGITS)

self.intensity = intensity

self.init()

def init(self):

for command, data in (

(REG_SHUTDOWN, 0),

(REG_DECODE_MODE, 0),

(REG_INTENSITY, self.intensity),

(REG_SCAN_LIMIT, 7),

(REG_DISPLAY_TEST, 0),

(REG_SHUTDOWN, 1),

):

self.set_register(command, data)

def set_register(self, register, value):

self.spi.write(bytearray([value, register]))

def brightness(self, value):

if not 0 <= value <= 15:

raise ValueError("Brightness out of range")

self.set_register(REG_INTENSITY, value)

def fill(self, color):

data = 0xff if color else 0x00

for y in range(8):

self.buffer[y] = data

def pixel(self, x, y, color=None):

if color is None:

return bool(self.buffer[y] & 1 << x)

elif color:

self.buffer[y] |= 1 << x

else:

self.buffer[y] &= ~(1 << x)

def show(self):

for y in range(0,NUM_DIGITS):

self.set_register(REG_DIGIT_BASE + y, self.buffer[y])

Python - fonts_8x8.py

# bit patterns for the CP437 font

# Reference: http://www.gammon.com.au/forum/?id=11516

fonts_8x8 = [

[ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ], # 0x00

[ 0x7E, 0x81, 0x95, 0xB1, 0xB1, 0x95, 0x81, 0x7E ], # 0x01

[ 0x7E, 0xFF, 0xEB, 0xCF, 0xCF, 0xEB, 0xFF, 0x7E ], # 0x02

[ 0x0E, 0x1F, 0x3F, 0x7E, 0x3F, 0x1F, 0x0E, 0x00 ], # 0x03

[ 0x08, 0x1C, 0x3E, 0x7F, 0x3E, 0x1C, 0x08, 0x00 ], # 0x04

[ 0x18, 0xBA, 0xFF, 0xFF, 0xFF, 0xBA, 0x18, 0x00 ], # 0x05

[ 0x10, 0xB8, 0xFC, 0xFF, 0xFC, 0xB8, 0x10, 0x00 ], # 0x06

[ 0x00, 0x00, 0x18, 0x3C, 0x3C, 0x18, 0x00, 0x00 ], # 0x07

[ 0xFF, 0xFF, 0xE7, 0xC3, 0xC3, 0xE7, 0xFF, 0xFF ], # 0x08

[ 0x00, 0x3C, 0x66, 0x42, 0x42, 0x66, 0x3C, 0x00 ], # 0x09

[ 0xFF, 0xC3, 0x99, 0xBD, 0xBD, 0x99, 0xC3, 0xFF ], # 0x0A

[ 0x70, 0xF8, 0x88, 0x88, 0xFD, 0x7F, 0x07, 0x0F ], # 0x0B

[ 0x00, 0x4E, 0x5F, 0xF1, 0xF1, 0x5F, 0x4E, 0x00 ], # 0x0C

[ 0xC0, 0xE0, 0xFF, 0x7F, 0x05, 0x05, 0x07, 0x07 ], # 0x0D

[ 0xC0, 0xFF, 0x7F, 0x05, 0x05, 0x65, 0x7F, 0x3F ], # 0x0E

[ 0x99, 0x5A, 0x3C, 0xE7, 0xE7, 0x3C, 0x5A, 0x99 ], # 0x0F

[ 0x7F, 0x3E, 0x3E, 0x1C, 0x1C, 0x08, 0x08, 0x00 ], # 0x10

[ 0x08, 0x08, 0x1C, 0x1C, 0x3E, 0x3E, 0x7F, 0x00 ], # 0x11

[ 0x00, 0x24, 0x66, 0xFF, 0xFF, 0x66, 0x24, 0x00 ], # 0x12

[ 0x00, 0x5F, 0x5F, 0x00, 0x00, 0x5F, 0x5F, 0x00 ], # 0x13

[ 0x06, 0x0F, 0x09, 0x7F, 0x7F, 0x01, 0x7F, 0x7F ], # 0x14

[ 0x40, 0xDA, 0xBF, 0xA5, 0xFD, 0x59, 0x03, 0x02 ], # 0x15

[ 0x00, 0x70, 0x70, 0x70, 0x70, 0x70, 0x70, 0x00 ], # 0x16

[ 0x80, 0x94, 0xB6, 0xFF, 0xFF, 0xB6, 0x94, 0x80 ], # 0x17

[ 0x00, 0x04, 0x06, 0x7F, 0x7F, 0x06, 0x04, 0x00 ], # 0x18

[ 0x00, 0x10, 0x30, 0x7F, 0x7F, 0x30, 0x10, 0x00 ], # 0x19

[ 0x08, 0x08, 0x08, 0x2A, 0x3E, 0x1C, 0x08, 0x00 ], # 0x1A

[ 0x08, 0x1C, 0x3E, 0x2A, 0x08, 0x08, 0x08, 0x00 ], # 0x1B

[ 0x3C, 0x3C, 0x20, 0x20, 0x20, 0x20, 0x20, 0x00 ], # 0x1C

[ 0x08, 0x1C, 0x3E, 0x08, 0x08, 0x3E, 0x1C, 0x08 ], # 0x1D

[ 0x30, 0x38, 0x3C, 0x3E, 0x3E, 0x3C, 0x38, 0x30 ], # 0x1E

[ 0x06, 0x0E, 0x1E, 0x3E, 0x3E, 0x1E, 0x0E, 0x06 ], # 0x1F

[ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ], # ' '

[ 0x00, 0x06, 0x5F, 0x5F, 0x06, 0x00, 0x00, 0x00 ], # '!'

[ 0x00, 0x07, 0x07, 0x00, 0x07, 0x07, 0x00, 0x00 ], # '"'

[ 0x14, 0x7F, 0x7F, 0x14, 0x7F, 0x7F, 0x14, 0x00 ], # '#'

[ 0x24, 0x2E, 0x6B, 0x6B, 0x3A, 0x12, 0x00, 0x00 ], # '$'

[ 0x46, 0x66, 0x30, 0x18, 0x0C, 0x66, 0x62, 0x00 ], # '%'

[ 0x30, 0x7A, 0x4F, 0x5D, 0x37, 0x7A, 0x48, 0x00 ], # '&'

[ 0x04, 0x07, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00 ], # '''

[ 0x00, 0x1C, 0x3E, 0x63, 0x41, 0x00, 0x00, 0x00 ], # '('

[ 0x00, 0x41, 0x63, 0x3E, 0x1C, 0x00, 0x00, 0x00 ], # ')'

[ 0x08, 0x2A, 0x3E, 0x1C, 0x1C, 0x3E, 0x2A, 0x08 ], # '*'

[ 0x08, 0x08, 0x3E, 0x3E, 0x08, 0x08, 0x00, 0x00 ], # '+'

[ 0x00, 0x80, 0xE0, 0x60, 0x00, 0x00, 0x00, 0x00 ], # ','

[ 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x00, 0x00 ], # '-'

[ 0x00, 0x00, 0x60, 0x60, 0x00, 0x00, 0x00, 0x00 ], # '.'

[ 0x60, 0x30, 0x18, 0x0C, 0x06, 0x03, 0x01, 0x00 ], # '/'

[ 0x3E, 0x7F, 0x71, 0x59, 0x4D, 0x7F, 0x3E, 0x00 ], # '0'

[ 0x40, 0x42, 0x7F, 0x7F, 0x40, 0x40, 0x00, 0x00 ], # '1'

[ 0x62, 0x73, 0x59, 0x49, 0x6F, 0x66, 0x00, 0x00 ], # '2'

[ 0x22, 0x63, 0x49, 0x49, 0x7F, 0x36, 0x00, 0x00 ], # '3'

[ 0x18, 0x1C, 0x16, 0x53, 0x7F, 0x7F, 0x50, 0x00 ], # '4'

[ 0x27, 0x67, 0x45, 0x45, 0x7D, 0x39, 0x00, 0x00 ], # '5'

[ 0x3C, 0x7E, 0x4B, 0x49, 0x79, 0x30, 0x00, 0x00 ], # '6'

[ 0x03, 0x03, 0x71, 0x79, 0x0F, 0x07, 0x00, 0x00 ], # '7'

[ 0x36, 0x7F, 0x49, 0x49, 0x7F, 0x36, 0x00, 0x00 ], # '8'

[ 0x06, 0x4F, 0x49, 0x69, 0x3F, 0x1E, 0x00, 0x00 ], # '9'

[ 0x00, 0x00, 0x66, 0x66, 0x00, 0x00, 0x00, 0x00 ], # ':'

[ 0x00, 0x80, 0xE6, 0x66, 0x00, 0x00, 0x00, 0x00 ], # ';'

[ 0x08, 0x1C, 0x36, 0x63, 0x41, 0x00, 0x00, 0x00 ], # '<'

[ 0x24, 0x24, 0x24, 0x24, 0x24, 0x24, 0x00, 0x00 ], # '='

[ 0x00, 0x41, 0x63, 0x36, 0x1C, 0x08, 0x00, 0x00 ], # '>'

[ 0x02, 0x03, 0x51, 0x59, 0x0F, 0x06, 0x00, 0x00 ], # '?'

[ 0x3E, 0x7F, 0x41, 0x5D, 0x5D, 0x1F, 0x1E, 0x00 ], # '@'

[ 0x7C, 0x7E, 0x13, 0x13, 0x7E, 0x7C, 0x00, 0x00 ], # 'A'

[ 0x41, 0x7F, 0x7F, 0x49, 0x49, 0x7F, 0x36, 0x00 ], # 'B'

[ 0x1C, 0x3E, 0x63, 0x41, 0x41, 0x63, 0x22, 0x00 ], # 'C'

[ 0x41, 0x7F, 0x7F, 0x41, 0x63, 0x3E, 0x1C, 0x00 ], # 'D'

[ 0x41, 0x7F, 0x7F, 0x49, 0x5D, 0x41, 0x63, 0x00 ], # 'E'

[ 0x41, 0x7F, 0x7F, 0x49, 0x1D, 0x01, 0x03, 0x00 ], # 'F'

[ 0x1C, 0x3E, 0x63, 0x41, 0x51, 0x73, 0x72, 0x00 ], # 'G'

[ 0x7F, 0x7F, 0x08, 0x08, 0x7F, 0x7F, 0x00, 0x00 ], # 'H'

[ 0x00, 0x41, 0x7F, 0x7F, 0x41, 0x00, 0x00, 0x00 ], # 'I'

[ 0x30, 0x70, 0x40, 0x41, 0x7F, 0x3F, 0x01, 0x00 ], # 'J'

[ 0x41, 0x7F, 0x7F, 0x08, 0x1C, 0x77, 0x63, 0x00 ], # 'K'

[ 0x41, 0x7F, 0x7F, 0x41, 0x40, 0x60, 0x70, 0x00 ], # 'L'

[ 0x7F, 0x7F, 0x0E, 0x1C, 0x0E, 0x7F, 0x7F, 0x00 ], # 'M'

[ 0x7F, 0x7F, 0x06, 0x0C, 0x18, 0x7F, 0x7F, 0x00 ], # 'N'

[ 0x1C, 0x3E, 0x63, 0x41, 0x63, 0x3E, 0x1C, 0x00 ], # 'O'

[ 0x41, 0x7F, 0x7F, 0x49, 0x09, 0x0F, 0x06, 0x00 ], # 'P'

[ 0x1E, 0x3F, 0x21, 0x71, 0x7F, 0x5E, 0x00, 0x00 ], # 'Q'

[ 0x41, 0x7F, 0x7F, 0x09, 0x19, 0x7F, 0x66, 0x00 ], # 'R'

[ 0x26, 0x6F, 0x4D, 0x59, 0x73, 0x32, 0x00, 0x00 ], # 'S'

[ 0x03, 0x41, 0x7F, 0x7F, 0x41, 0x03, 0x00, 0x00 ], # 'T'

[ 0x7F, 0x7F, 0x40, 0x40, 0x7F, 0x7F, 0x00, 0x00 ], # 'U'

[ 0x1F, 0x3F, 0x60, 0x60, 0x3F, 0x1F, 0x00, 0x00 ], # 'V'

[ 0x7F, 0x7F, 0x30, 0x18, 0x30, 0x7F, 0x7F, 0x00 ], # 'W'

[ 0x43, 0x67, 0x3C, 0x18, 0x3C, 0x67, 0x43, 0x00 ], # 'X'

[ 0x07, 0x4F, 0x78, 0x78, 0x4F, 0x07, 0x00, 0x00 ], # 'Y'

[ 0x47, 0x63, 0x71, 0x59, 0x4D, 0x67, 0x73, 0x00 ], # 'Z'

[ 0x00, 0x7F, 0x7F, 0x41, 0x41, 0x00, 0x00, 0x00 ], # '['

[ 0x01, 0x03, 0x06, 0x0C, 0x18, 0x30, 0x60, 0x00 ], # backslash

[ 0x00, 0x41, 0x41, 0x7F, 0x7F, 0x00, 0x00, 0x00 ], # ']'

[ 0x08, 0x0C, 0x06, 0x03, 0x06, 0x0C, 0x08, 0x00 ], # '^'

[ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80 ], # '_'

[ 0x00, 0x00, 0x03, 0x07, 0x04, 0x00, 0x00, 0x00 ], # '`'

[ 0x20, 0x74, 0x54, 0x54, 0x3C, 0x78, 0x40, 0x00 ], # 'a'

[ 0x41, 0x7F, 0x3F, 0x48, 0x48, 0x78, 0x30, 0x00 ], # 'b'

[ 0x38, 0x7C, 0x44, 0x44, 0x6C, 0x28, 0x00, 0x00 ], # 'c'

[ 0x30, 0x78, 0x48, 0x49, 0x3F, 0x7F, 0x40, 0x00 ], # 'd'

[ 0x38, 0x7C, 0x54, 0x54, 0x5C, 0x18, 0x00, 0x00 ], # 'e'

[ 0x48, 0x7E, 0x7F, 0x49, 0x03, 0x02, 0x00, 0x00 ], # 'f'

[ 0x98, 0xBC, 0xA4, 0xA4, 0xF8, 0x7C, 0x04, 0x00 ], # 'g'

[ 0x41, 0x7F, 0x7F, 0x08, 0x04, 0x7C, 0x78, 0x00 ], # 'h'

[ 0x00, 0x44, 0x7D, 0x7D, 0x40, 0x00, 0x00, 0x00 ], # 'i'

[ 0x60, 0xE0, 0x80, 0x80, 0xFD, 0x7D, 0x00, 0x00 ], # 'j'

[ 0x41, 0x7F, 0x7F, 0x10, 0x38, 0x6C, 0x44, 0x00 ], # 'k'

[ 0x00, 0x41, 0x7F, 0x7F, 0x40, 0x00, 0x00, 0x00 ], # 'l'

[ 0x7C, 0x7C, 0x18, 0x38, 0x1C, 0x7C, 0x78, 0x00 ], # 'm'

[ 0x7C, 0x7C, 0x04, 0x04, 0x7C, 0x78, 0x00, 0x00 ], # 'n'

[ 0x38, 0x7C, 0x44, 0x44, 0x7C, 0x38, 0x00, 0x00 ], # 'o'

[ 0x84, 0xFC, 0xF8, 0xA4, 0x24, 0x3C, 0x18, 0x00 ], # 'p'

[ 0x18, 0x3C, 0x24, 0xA4, 0xF8, 0xFC, 0x84, 0x00 ], # 'q'

[ 0x44, 0x7C, 0x78, 0x4C, 0x04, 0x1C, 0x18, 0x00 ], # 'r'

[ 0x48, 0x5C, 0x54, 0x54, 0x74, 0x24, 0x00, 0x00 ], # 's'

[ 0x00, 0x04, 0x3E, 0x7F, 0x44, 0x24, 0x00, 0x00 ], # 't'

[ 0x3C, 0x7C, 0x40, 0x40, 0x3C, 0x7C, 0x40, 0x00 ], # 'u'

[ 0x1C, 0x3C, 0x60, 0x60, 0x3C, 0x1C, 0x00, 0x00 ], # 'v'

[ 0x3C, 0x7C, 0x70, 0x38, 0x70, 0x7C, 0x3C, 0x00 ], # 'w'

[ 0x44, 0x6C, 0x38, 0x10, 0x38, 0x6C, 0x44, 0x00 ], # 'x'

[ 0x9C, 0xBC, 0xA0, 0xA0, 0xFC, 0x7C, 0x00, 0x00 ], # 'y'

[ 0x4C, 0x64, 0x74, 0x5C, 0x4C, 0x64, 0x00, 0x00 ], # 'z'

[ 0x08, 0x08, 0x3E, 0x77, 0x41, 0x41, 0x00, 0x00 ], # '{'

[ 0x00, 0x00, 0x00, 0x77, 0x77, 0x00, 0x00, 0x00 ], # '|'

[ 0x41, 0x41, 0x77, 0x3E, 0x08, 0x08, 0x00, 0x00 ], # '}'

[ 0x02, 0x03, 0x01, 0x03, 0x02, 0x03, 0x01, 0x00 ], # '~'

[ 0x70, 0x78, 0x4C, 0x46, 0x4C, 0x78, 0x70, 0x00 ], # 0x7F

] # end of cp437_font

Python - MAX7219_Matrix_Test.py

from machine import Switch #獲取按鍵KEY庫

from machine import SPI

import MAX7219

import fonts_8x8

import utime

ePyCloud = [0x08, 0xFE, 0x6A, 0x5F, 0x5F, 0x6A, 0x7E, 0x08]

symbol=[

[0x00, 0x98, 0xE4, 0x1F, 0x1F, 0xE4, 0x98, 0x00],

[0x00, 0x90, 0xCB, 0x2F, 0x1D, 0x24, 0x44, 0x88],

[0x00, 0x90, 0xDB, 0x2F, 0x1D, 0x24, 0x44, 0x88],

[0x00, 0x00, 0xDB, 0x2F, 0x1D, 0x64, 0x88, 0x00],

[0x00, 0x00, 0x03, 0x1F, 0x7D, 0xE8, 0x80, 0x00],

[0x00, 0x00, 0xDB, 0x2F, 0x1D, 0x64, 0x88, 0x00]]

face = [

[0x3C, 0x42, 0xA5, 0x81, 0xA5, 0x98, 0x42, 0x3C],

[0x3C, 0x42, 0xA5, 0x81, 0xBD, 0x81, 0x42, 0x3C],

[0x3C, 0x42, 0xA5, 0x81, 0x99, 0xA5, 0x42, 0x3C]]

spi0 = None

spi0 = SPI(0, SPI.MASTER, baudrate=5000000, polarity=1, phase=0, bits=16) #For Hardware SPI bus

# Start Function

if __name__ == '__main__':

display = MAX7219.Matrix8x8(spi0)

# display.brightness(7)

display.fill(False)

display.show()

utime.sleep(1)

# display.fill(False)

# display.pixel(4, 4, True)

# display.show()

# utime.sleep(1)

for y in range(8):

display.buffer[y] = ePyCloud[y]

display.show()

utime.sleep(2)

for y in range(8):

display.buffer[y] = symbol[0][y]

display.show()

utime.sleep(2)

for z in range(20):

for x in range(1,6):

for y in range(8):

display.buffer[y] = symbol[x][y]

display.show()

utime.sleep_ms(200)

for x in range(10):

for y in range(8):

display.buffer[y] = fonts_8x8.fonts_8x8[x+0x30][y]

display.show()

utime.sleep_ms(1000)

for x in range(26):

for y in range(8):

display.buffer[y] = fonts_8x8.fonts_8x8[x+0x41][y]

display.show()

utime.sleep_ms(1000)

display.fill(False)

display.show()

utime.sleep(1)

spi0 .deinit()

執行結果