SPI串列通訊實作Part2 – MAX7219 7段LED顯示

SPI串列通訊實作Part2 – MAX7219 7段LED顯示

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程式列表

• max7219_8digit.py

# Reference: #   Micropython driver for the max7219 with 8 x 7segment display #   https://github.com/pdwerryhouse/max7219_8digit   CHAR_MAP = {   ' ': 0x00, '0': 0x7e, '1': 0x30, '2': 0x6d,   '3': 0x79, '4': 0x33, '5': 0x5b, '6': 0x5f,   '7': 0x70, '8': 0x7f, '9': 0x7b, 'a': 0x77,   'b': 0x1f, 'c': 0x4e, 'd': 0x3d, 'e': 0x4f,   'f': 0x47, 'g': 0x7b, 'h': 0x37, 'i': 0x30,   'j': 0x3c, 'k': 0x57, 'l': 0x0e, 'm': 0x54,   'n': 0x15, 'o': 0x1d, 'p': 0x67, 'q': 0x73,   'r': 0x05, 's': 0x5b, 't': 0x0f, 'u': 0x1c,   'v': 0x3e, 'w': 0x2a, 'x': 0x37, 'y': 0x3b,   'z': 0x6d, 'A': 0x77, 'B': 0x1f, 'C': 0x4e,   'D': 0x3d, 'E': 0x4f, 'F': 0x47, 'G': 0x7b,   'H': 0x37, 'I': 0x30, 'J': 0x3c, 'K': 0x57,   'L': 0x0e, 'M': 0x54, 'N': 0x15, 'O': 0x1d,   'P': 0x67, 'Q': 0x73, 'R': 0x05, 'S': 0x5b,   'T': 0x0f, 'U': 0x1c, 'V': 0x3e, 'W': 0x2a,   'X': 0x37, 'Y': 0x3b, 'Z': 0x6d, ' ': 0x00,   '-': 0x01, '\xb0': 0x63, '.': 0x80 }   REG_NO_OP       = const(0x00) REG_DIGIT_BASE  = const(0x01) REG_DIGIT0      = const(0x01) REG_DIGIT1      = const(0x02) REG_DIGIT2      = const(0x03) REG_DIGIT3      = const(0x04) REG_DIGIT4      = const(0x05) REG_DIGIT5      = const(0x06) REG_DIGIT6      = const(0x07) REG_DIGIT7      = const(0x08) REG_DECODE_MODE = const(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   = const(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  = const(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    = const(0x0C)   #Shutdown Register Format   # 0x00  Shutdown Mode   # 0x01  Normal Operation REG_DISPLAY_TEST  = const(0x0F)   #Display-Test Register Format   # 0x00  Normal Operation   # 0x01  Display Test Mode   NUM_DIGITS      = 8   class Display7seg:   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_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 write_to_buffer(self, s):     l = len(s)     if l < NUM_DIGITS:       s = "%-8s" % s     for i in range(0,NUM_DIGITS):       self.buffer[7-i] = self.decode_char(s[i])     def decode_char(self, c):     d = CHAR_MAP.get(c)     return d if d != None else ' '     def write_number(self, value, zeroPad=False, leftJustify=False):     # Take number, format it, look up characters then pass to buffer.       if len(str(value)) > NUM_DIGITS:       raise OverflowError('{0} too large for display'.format(value))       size = NUM_DIGITS     formatStr = '%'       if zeroPad:       formatStr += '0'       if leftJustify:       size *= -1       formatStr = '{fmt}{size}i'.format(fmt=formatStr, size=size)     position = REG_DIGIT7     strValue = formatStr % value       # look up each digit's character     # then send to buffer     for char in strValue:       self.buffer[position - 1] = self.letter(char)       position -= 1     def letter(self, char):     # Look up character on digits table & return     value = CHAR_MAP.get(str(char))     return value     def intensity(self, i):     self.send(self.intensity, i)     def show(self):     for y in range(0,NUM_DIGITS):       self.set_register(REG_DIGIT_BASE + y, self.buffer[y])

 

• max7219_8digit_Test.py

from machine import KEY  #獲取按鍵KEY庫 from machine import SPI, PIN import max7219_8digit import utime   # Connections: # 腳位定義  SPI0  SPI1     MAX7219 # 3V3                      VCC # GND                      GND # MOSI       P15  P26  ->  DIN # CS         P16  P23  ->  CS # CLK        P13  P24  ->  CLK # MISO       P14  P25  ->  DOUT   spi_1  = None spi_1 =SPI(1, mode=SPI.MASTER, baudrate=5000000, polarity=1, phase=0) #For Hardware SPI bus          #baudrate is the SCK clock rate.          #polarity can be 0 or 1, and is the level the idle clock line sits at.          #phase can be 0 or 1 to sample data on the first or second clock edge respectively.          #bits is the width in bits of each transfer. Only 8 is guaranteed to be supported by all hardware.          #firstbit can be SPI.MSB or SPI.LSB.   # Start Function if __name__ == '__main__':   key_c = KEY(KEY.KEYC)    #創建按鍵C     display = max7219_8digit.Display7seg(spi_1)   display.write_to_buffer('EPYTHON')   display.show()   utime.sleep_ms(1000)     for NUM in range(0,50000):     display.write_number(NUM)     display.show()       if key_c.value() == 0:      #如果按鍵C被按下       break     utime.sleep_ms(100)   spi_1 .deinit()