Add OpenLASIR protocol support

README.md

@@ -52,7 +52,8 @@ The drivers support NEC and Sony protocols plus two Philips protocols, namely
 RC-5 and RC-6 mode 0. There is also support for the OrtekMCE protocol used on
 VRC-1100 remotes. These originally supported Microsoft Media Center but can be
 used to control Kodi and (with a suitable receiver) to emulate a PC keyboard.
-The Samsung protocol (NEC variant) is also supported.
+The Samsung protocol (NEC variant) is also supported. The OpenLASIR protocol 
+(another NEC variant) is supported too.
 
 Examining waveforms from various remote controls it is evident that numerous
 protocols exist. Some are doubtless proprietary and undocumented. The supported
@@ -95,6 +96,7 @@ protocol and is not supported by these drivers.
 | MCE       | 38    | Measured      | Y       | 
 | Samsung   | 38    | Measured      | Y       |
 | Panasonic | 36.3  | Measured      | N       |
+| OpenLASIR | 38    | Spec          | Y       |
 
 # 4. Receiver limitations
 
@@ -133,6 +135,10 @@ Sony protocol:
 MCE protocol:  
 [OrtekMCE](http://www.hifi-remote.com/johnsfine/DecodeIR.html#OrtekMCE)
 
+OpenLASIR protocol:
+[GitHub](https://github.com/danielweidman/OpenLASIR)
+
+
 IR decoders (C sourcecode):  
 [in the Linux kernel](https://github.com/torvalds/linux/tree/master/drivers/media/rc)
 

RECEIVER.md

@@ -229,6 +229,17 @@ could find stated that the value should be 3. I implemented this as a class
 variable `MCE.init_cs=4`. This enables it to be changed if some remotes use 3.
 If the value is set to -1 the check will be skipped.
 
+#### OpenLASIR class
+
+`OpenLASIR`
+
+Typical invocation:
+```python
+from ir_rx.openlasir import OpenLASIR
+```
+
+This supports the physical IR layer for [OpenLASIR](https://github.com/danielweidman/OpenLASIR).
+
 # 4. Errors
 
 IR reception is inevitably subject to errors, notably if the remote is operated

TRANSMITTER.md

@@ -272,6 +272,15 @@ I could find stated that the value should be 3. I implemented this as a class
 variable `MCE.init_cs=4`. This enables it to be changed if some receivers
 require 3.
 
+#### OpenLASIR class
+
+Class `OpenLASIR`. Example invocation:
+```python
+from ir_tx.openlasir import OpenLASIR
+```
+
+The [OpenLASIR](https://github.com/danielweidman/OpenLASIR) protocol uses an 8 bit address and 16 bit command.
+
 # 4. Principle of operation
 
 The classes inherit from the abstract base class `IR`. This has an array `.arr`

ir_rx/openlasir.py

@@ -0,0 +1,52 @@
+# Decoder for OpenLASIR IR protocol.
+# Similar to NEC Extended, but error checking is on the address (first 8 bits inverted 
+# in second 8 bits) instead of on the command, giving an 8-bit validated address and 
+# 16-bit command.
+# Full protocol spec: https://github.com/danielweidman/OpenLASIR
+
+# Strongly based on NEC decoder by Peter Hinch (MIT license)
+from utime import ticks_us, ticks_diff
+from ir_rx import IR_RX
+
+
+class OpenLASIR(IR_RX):
+    def __init__(self, pin, callback, *args):
+        # Block lasts <= 80ms and has 68 edges
+        super().__init__(pin, 68, 80, callback, *args)
+        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 562.5us)
+                # Space is 1.6875ms (1) or 562.5us (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
+                raise RuntimeError(self.REPEAT if self.edge == 4 else self.BADREP)
+            else:
+                raise RuntimeError(self.BADSTART)
+            addr = val & 0xff  # First 8 bits of address
+            # Error check: second 8 bits must be the inverted first 8 bits
+            if addr != ((val >> 8) ^ 0xff) & 0xff:
+                raise RuntimeError(self.BADADDR)
+            # Command is full 16 bits with no error check
+            cmd = (val >> 16) & 0xffff
+            self._addr = addr
+        except RuntimeError as e:
+            cmd = e.args[0]
+            addr = self._addr if cmd == self.REPEAT else 0
+        # Set up for new data burst and run user callback
+        self.do_callback(cmd, addr, 0, self.REPEAT)

ir_tx/openlasir.py

@@ -0,0 +1,41 @@
+# Encoder for OpenLASIR IR protocol.
+# Similar to NEC Extended, but error checking is on the address (first 8 bits inverted 
+# in second 8 bits) instead of on the command, giving an 8-bit validated address and 
+# 16-bit command.
+# Full protocol spec: https://github.com/danielweidman/OpenLASIR
+
+# Strongly based on NEC encoder by Peter Hinch (MIT license)
+from micropython import const
+from ir_tx import IR, STOP
+
+_TBURST = const(563)
+_T_ONE = const(1687)
+
+
+class OpenLASIR(IR):
+    valid = (0xff, 0xffff, 0)  # Max addr (8-bit), data (16-bit), toggle
+
+    def __init__(self, pin, freq=38000, verbose=False):
+        super().__init__(pin, freq, 68, 33, verbose)  # Measured duty ratio 33%
+
+    def _bit(self, b):
+        self.append(_TBURST, _T_ONE if b else _TBURST)
+
+    def tx(self, addr, data, _):  # Ignore toggle
+        self.append(9000, 4500)
+        # Address: 8-bit with inverted complement for error checking
+        addr &= 0xff
+        addr |= ((addr ^ 0xff) << 8)
+        for _ in range(16):
+            self._bit(addr & 1)
+            addr >>= 1
+        # Data/command: 16-bit, sent as-is with no error checking
+        for _ in range(16):
+            self._bit(data & 1)
+            data >>= 1
+        self.append(_TBURST)
+
+    def repeat(self):
+        self.aptr = 0
+        self.append(9000, 2250, _TBURST)
+        self.trigger()  # Initiate physical transmission.