ir_tx/mce.py

   1 # mce.py Encoder for IR remote control using synchronous code
   2 # Supports Microsoft MCE edition remote protocol.
   3
   4 # Author: Peter Hinch
   5 # Copyright Peter Hinch 2020 Released under the MIT license
   6
   7 # WARNING: This is experimental and subject to change.
   8
   9 from micropython import const
  10 from ir_tx import IR
  11
  12 _TBIT = const(500)  # Time (μs) for pulse of carrier
  13
  14
  15 class MCE(IR):
  16     valid = (0xf, 0x3f, 3)  # Max addr, data, toggle
  17     init_cs = 4  # http://www.hifi-remote.com/johnsfine/DecodeIR.html#OrtekMCE says 3
  18
  19     def __init__(self, pin, freq=38000, verbose=False):
  20         super().__init__(pin, freq, 34, 30, verbose)
  21
  22     def tx(self, addr, data, toggle):
  23         def checksum(v):
  24             cs = self.init_cs
  25             for _ in range(12):
  26                 if v & 1:
  27                     cs += 1
  28                 v >>= 1
  29             return cs
  30
  31         self.append(2000, 1000, _TBIT)
  32         d = ((data & 0x3f) << 6) | (addr & 0xf)  | ((toggle & 3) << 4)
  33         d |= checksum(d) << 12
  34         self.verbose and print(bin(d))
  35
  36         mask = 1
  37         while mask < 0x10000:
  38             bit = bool(d & mask)
  39             if bit ^ self.carrier:
  40                 self.add(_TBIT)
  41                 self.append(_TBIT)
  42             else:
  43                 self.append(_TBIT, _TBIT)
  44             mask <<= 1