Receiver now a package.

[micorpython_ir.git] / ir_rx / nec.py

diff --git a/ir_rx/nec.py b/ir_rx/nec.py
new file mode 100644 (file)
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+++ b/ir_rx/nec.py
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+# nec.py Decoder for IR remote control using synchronous code
+# Supports NEC protocol.
+# For a remote using NEC see https://www.adafruit.com/products/389
+
+# Author: Peter Hinch
+# Copyright Peter Hinch 2020 Released under the MIT license
+
+from utime import ticks_us, ticks_diff
+from ir_rx import IR_RX
+
+class NEC_ABC(IR_RX):
+    def __init__(self, pin, extended, callback, *args):
+        # Block lasts <= 80ms (extended mode) and has 68 edges
+        super().__init__(pin, 68, 80, callback, *args)
+        self._extended = extended
+        self._addr = 0
+
+    def decode(self, _):
+        try:
+            if self.edge > 68:
+                raise RuntimeError(self.OVERRUN)
+            width = ticks_diff(self._times[1], self._times[0])
+            if width < 4000:  # 9ms leading mark for all valid data
+                raise RuntimeError(self.BADSTART)
+            width = ticks_diff(self._times[2], self._times[1])
+            if width > 3000:  # 4.5ms space for normal data
+                if self.edge < 68:  # Haven't received the correct number of edges
+                    raise RuntimeError(self.BADBLOCK)
+                # Time spaces only (marks are always 562.5µs)
+                # Space is 1.6875ms (1) or 562.5µs (0)
+                # Skip last bit which is always 1
+                val = 0
+                for edge in range(3, 68 - 2, 2):
+                    val >>= 1
+                    if ticks_diff(self._times[edge + 1], self._times[edge]) > 1120:
+                        val |= 0x80000000
+            elif width > 1700: # 2.5ms space for a repeat code. Should have exactly 4 edges.
+                raise RuntimeError(self.REPEAT if self.edge == 4 else self.BADREP)  # Treat REPEAT as error.
+            else:
+                raise RuntimeError(self.BADSTART)
+            addr = val & 0xff  # 8 bit addr
+            cmd = (val >> 16) & 0xff
+            if cmd != (val >> 24) ^ 0xff:
+                raise RuntimeError(self.BADDATA)
+            if addr != ((val >> 8) ^ 0xff) & 0xff:  # 8 bit addr doesn't match check
+                if not self._extended:
+                    raise RuntimeError(self.BADADDR)
+                addr |= val & 0xff00  # pass assumed 16 bit address to callback
+            self._addr = addr
+        except RuntimeError as e:
+            cmd = e.args[0]
+            addr = self._addr if cmd == self.REPEAT else 0  # REPEAT uses last address
+        # Set up for new data burst and run user callback
+        self.do_callback(cmd, addr, 0, self.REPEAT)
+
+class NEC_8(NEC_ABC):
+    def __init__(self, pin, callback, *args):
+        super().__init__(pin, False, callback, *args)
+
+class NEC_16(NEC_ABC):
+    def __init__(self, pin, callback, *args):
+        super().__init__(pin, True, callback, *args)