SPI串列通訊實作Part2 – MAX7219 7段LED顯示
電路圖
程式列表
- max7219_8digit.py
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# 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
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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() |
