Add MCE. Fix bug with RC5X.

[micorpython_ir.git] / ir_rx / mce.py

diff --git a/ir_rx/mce.py b/ir_rx/mce.py
new file mode 100644 (file)
index 0000000..218c859
--- /dev/null
+++ b/ir_rx/mce.py
@@ -0,0 +1,69 @@
+# mce.py Decoder for IR remote control using synchronous code
+# Supports Microsoft MCE edition remote protocol.
+
+# Author: Peter Hinch
+# Copyright Peter Hinch 2020 Released under the MIT license
+
+# WARNING: This is experimental and subject to change.
+
+from utime import ticks_us, ticks_diff
+from ir_rx import IR_RX
+
+class MCE(IR_RX):
+    init_cs = 4  # http://www.hifi-remote.com/johnsfine/DecodeIR.html#OrtekMCE says 3
+    def __init__(self, pin, callback, *args):
+        # Block lasts ~19ms and has <= 34 edges
+        super().__init__(pin, 34, 25, callback, *args)
+
+    def decode(self, _):
+        def check(v):
+            if self.init_cs == -1:
+                return True
+            csum = v >> 12
+            cs = self.init_cs
+            for _ in range(12):
+                if v & 1:
+                    cs += 1
+                v >>= 1
+            return cs == csum
+
+        try:
+            t0 = ticks_diff(self._times[1], self._times[0])  # 2000μs mark
+            t1 = ticks_diff(self._times[2], self._times[1])  # 1000μs space
+            if not ((1800 < t0 < 2200) and (800 < t1 < 1200)):
+                raise RuntimeError(self.BADSTART)
+            nedges = self.edge  # No. of edges detected
+            if not 14 <= nedges <= 34:
+                raise RuntimeError(self.OVERRUN if nedges > 28 else self.BADSTART)
+            # Manchester decode
+            mask = 1
+            bit = 1
+            v = 0
+            x = 2
+            for _ in range(16):
+                # -1 convert count to index, -1 because we look ahead
+                if x > nedges - 2:
+                    raise RuntimeError(self.BADBLOCK)
+                # width is 500/1000 nominal
+                width = ticks_diff(self._times[x + 1], self._times[x])
+                if not 250 < width < 1350:
+                    self.verbose and print('Bad block 3 Width', width, 'x', x)
+                    raise RuntimeError(self.BADBLOCK)
+                short = int(width < 750)
+                bit ^= short ^ 1
+                v |= mask if bit else 0
+                mask <<= 1
+                x += 1 + short
+
+            self.verbose and print(bin(v))
+            print(bin(v))  # TEST
+            #if not check(v):
+                #raise RuntimeError(self.BADDATA)
+            val = (v >> 6) & 0x3f
+            addr = v & 0xf  # Constant for all buttons on my remote
+            ctrl = (v >> 4) & 3
+
+        except RuntimeError as e:
+            val, addr, ctrl = e.args[0], 0, 0
+        # Set up for new data burst and run user callback/error function
+        self.do_callback(val, addr, ctrl)