71 lines
2.6 KiB
Python
71 lines
2.6 KiB
Python
from machine import Pin, Timer
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class Wiegand:
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def __init__(self, pin0, pin1, callback, buf_len=34):
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self.pin0 = Pin(pin0, Pin.IN, Pin.PULL_UP)
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self.pin1 = Pin(pin1, Pin.IN, Pin.PULL_UP)
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self.callback = callback
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self.buf = bytearray(buf_len)
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self.idx = 0
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self.timer = Timer(-1)
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self.pin0.irq(trigger=Pin.IRQ_FALLING, handler=self._irq)
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self.pin1.irq(trigger=Pin.IRQ_FALLING, handler=self._irq)
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def _irq(self, p):
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# 同时读取两根线，组合成 0b01 (bit=0) 或 0b10 (bit=1)
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state = (self.pin1.value() << 1) | self.pin0.value()
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if state not in (0b01, 0b10):
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return
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if self.idx < len(self.buf):
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self.buf[self.idx] = state
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self.idx += 1
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if self.idx == 1:
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# 只启动一次，80ms 后触发解析
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self.timer.init(period=80, mode=Timer.ONE_SHOT, callback=self._timeout)
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def _timeout(self, t):
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n = self.idx
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self.idx = 0
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data = bytes(self.buf[:n]) # 拷贝，防止中断覆盖
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self._parse(n, data)
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def _parse(self, n, data):
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if n == 26 and self._check_parity(data, 26):
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# 剔除首尾校验位，保留中间 24 位有效载荷
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payload = self._extract_bits(data, 1, 24)
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self.callback('wg26', payload)
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elif n == 34 and self._check_parity(data, 34):
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# 剔除首尾校验位，保留中间 32 位有效载荷
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payload = self._extract_bits(data, 1, 32)
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self.callback('wg34', payload)
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elif n == 8:
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# 键盘：低4位键值，高4位为低4位取反
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val = self._extract_bits(data, 0, 8)
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if ((val >> 4) ^ (val & 0x0F)) == 0x0F:
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self.callback('keypad', val & 0x0F)
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# 其余长度或校验失败直接丢弃
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def _check_parity(self, data, bits):
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"""标准 Wiegand 奇偶校验：前一半偶数个1，后一半奇数个1"""
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half = bits // 2
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cnt_even = 0
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cnt_odd = 0
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for i in range(bits):
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if data[i] == 0b10: # 该比特为 1
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if i < half:
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cnt_even += 1
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else:
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cnt_odd += 1
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return (cnt_even % 2 == 0) and (cnt_odd % 2 == 1)
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def _extract_bits(self, data, start, count):
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"""从 data 中提取连续比特，MSB first，返回整数"""
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val = 0
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for i in range(start, start + count):
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val <<= 1
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if data[i] == 0b10:
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val |= 1
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return val
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