max7219.py

# max7219 test
# Registers and associated values
# Registers and associated values
_NOOP = const(0x0)  # Used when cascading Max7219
_DIGIT0 = const(0x1)
_DIGIT1 = const(0x2)
_DIGIT2 = const(0x3)
_DIGIT3 = const(0x4)
_DIGIT4 = const(0x5)
_DIGIT5 = const(0x6)
_DIGIT6 = const(0x7)
_DIGIT7 = const(0x8)
_DECODEMODE = const(0x9)    # (0 = no decode/raw segment values, 1 = decode only digit 0, 0xFF = decode on all digits)
_INTENSITY = const(0xA)     # (0 = lowest intensity, 0xF = max intensity)
_SCANLIMIT = const(0xB)     # (0 = display digit 0 only, 7 = display all 7 digits)
_SHUTDOWN = const(0xC)      # (0 = shutdown, 1 = normal operation)
_DISPLAYTEST = const(0xF)   # (0 = normal mode, 1 = test mode)

_HEX_TO_SEG = { 0x0: 0b01111110, 0x1: 0b0110000, 0x2: 0b1101101, 0x3: 0b1111001, 0x4: 0b0110011, 0x5: 0b1011011, 0x6: 0b1011111, 0x7: 0b1110000, 0x8: 0b1111111, 0x9: 0b1111011, 0xA: 0b1110111, 0xB: 0b0011111, 0xC: 0b1001110, 0xD: 0b0111101, 0xE: 0b1001111, 0xF: 0b1000111,}

class Max7219:
    def __init__(self, spi, cs):
        self.spi = spi
        self.cs = cs
        self.cs.init(cs.OUT, True)
        self.init()

    def register(self, command, data):
        self.cs.off()
        self.spi.write(bytearray([command, data]))
        self.cs.on()

    def setscan(self, data):
        self.cs.off()
        self.register(_SCANLIMIT, data)
        self.cs.on()
        
    def init(self):
        for command, data in (
            (_SHUTDOWN, 0), # Turn display off
            (_SCANLIMIT, 7),    # Display all 7 digits
            (_DECODEMODE, 0xFF),# Decode all digits 
            (_INTENSITY, 0x3),  # Set brightness to 3
            (_SHUTDOWN, 1), # Turn display on
        ):
            self.register(command, data)
            
    def brightness(self, value):
        if 0 <= value <= 15:
            self.register(_INTENSITY, value)
        else:
            raise ValueError("Brightness out of range")
        
    def clear(self):
        self.register(_DECODEMODE, 0xFF)
        for i in range(8):
            self.register(_DIGIT0 + i, 0x0)
            
    def write_num(self, value):
        self.register(_DECODEMODE, 0xFF)
        if (0 <= value <= 99999999):
            for i in range(8):
                self.register(_DIGIT0 + i, value % 10)
                value = value // 10
        elif (0 > value >= -9999999):
            value = -value
            self.register(_DIGIT7, 0xA)
            for i in range(7):
                self.register(_DIGIT0 + i, value % 10)
                value = value // 10
        else:
            raise ValueError("Value out of range")
        
    def write_numsc(self, value):
        if (value > 9999999):
            self.setscan(7)
            rng = 7
        elif (value > 999999):
            self.setscan(6)
            rng = 6
        elif (value > 99999):
            self.setscan(5)
            rng = 5
        elif (value > 9999):
            self.setscan(4)
            rng = 4
        elif (value > 999):
            self.setscan(3)
            rng = 3
        elif (value > 99):
            self.setscan(2)
            rng = 2
        elif (value > 9):
            self.setscan(1)
            rng = 1
        else:
            self.setscan(0)
            rng = 0
        for i in range(rng):
                self.register( _DIGIT0 + i, value % 10)
                value = value // 10
        
        
        
        
    def write_hex(self, value):
        self.register(_DECODEMODE, 0x0)
        if (0 <= value <= 99999999):
            for i in range(8):
                self.register(_DIGIT0 + i, _HEX_TO_SEG[value % 16])
                value = value // 16
        else:
            raise ValueError("Value out of range")