IR communication uses a carrier frequency to pulse the IR source. Modulation
takes the form of OOK (on-off keying). There are multiple protocols and at
-least two options for carrier frequency, namely 36KHz and 38KHz.
+least three options for carrier frequency, namely 36KHz, 38KHz and 40KHz.
-The drivers support the NEC protocol and two Philips protocols, namely RC-5 and
-RC-6 mode 0. In the case of the transmitter the carrier frequency is a runtime
-parameter: any value may be specified. The receiver uses a hardware demodulator
-which must be specified for the correct frequency. The receiver device driver
-sees the demodulated signal and is hence carrier frequency agnostic.
+The drivers support NEC and Sony protocols and two Philips protocols, namely
+RC-5 and RC-6 mode 0. In the case of the transmitter the carrier frequency is a
+runtime parameter: any value may be specified. The receiver uses a hardware
+demodulator which should be specified for the correct frequency. The receiver
+device driver sees the demodulated signal and is hence carrier frequency
+agnostic.
Examining waveforms from various remote controls it is evident that numerous
protocols exist. Some are doubtless proprietary and undocumented. The supported
microcontroller. The tested chip returns a 0 level on carrier detect, but the
driver design should ensure operation regardless of sense.
+In my testing a 38KHz demodulator worked with 36KHz and 40KHz remotes, but this
+is obviously not guaranteed or optimal.
+
The pin used to connect the decoder chip to the target is arbitrary but the
test programs assume pin X3 on the Pyboard, pin 13 on the ESP8266 and pin 23 on
ESP32.
# 4. Receiver
-This implements a class for each supported protocol, namely `NEC_IR`, `RC5_IR`
-and `RC6_M0`. Applications should instantiate the appropriate class with a
-callback. The callback will run whenever an IR pulsetrain is received.
+This implements a class for each supported protocol, namely `NEC_IR`,
+`SONY_IR`, `RC5_IR` and `RC6_M0`. Applications should instantiate the
+appropriate class with a callback. The callback will run whenever an IR pulse
+train is received.
Constructor:
`NEC_IR` args: `pin`, `callback`, `extended=True`, `*args`
+`SONY_IR` args: `pin`, `callback`, `bits=20`, `*args`
`RC5_IR` and `RC6_M0`: args `pin`, `callback`, `*args`
-Args:
+
+Args (all protocols):
1. `pin` is a `machine.Pin` instance configured as an input, connected to the
IR decoder chip.
2. `callback` is the user supplied callback (see below).
- 3. `extended` is an NEC specific boolean. Remotes using the NEC protocol can
+ 4. `*args` Any further args will be passed to the callback.
+
+Protocol specific args:
+ 1. `extended` is an NEC specific boolean. Remotes using the NEC protocol can
send 8 or 16 bit addresses. If `True` 16 bit addresses are assumed - an 8 bit
address will be correctly received. Set `False` to enable extra error checking
for remotes that return an 8 bit address.
- 4. `*args` Any further args will be passed to the callback.
+ 2. `bits=20` Sony specific. The SIRC protocol comes in 3 variants: 12, 15 and
+ 20 bits. The default will handle bitstreams from all three types of remote.
+ Choosing a value matching your remote improves the timing and reduces the
+ likelihood of errors when handling repeats: the SIRC timing when a button is
+ held down is tight in 20 bit mode.
The callback takes the following args:
1. `data` Integer value fom the remote. A negative value indicates an error
This is specific to Pyboard D and Pyboard 1.x (not Lite).
-It implements a class for each supported protocol, namely `NEC`, `RC5` and
-`RC6_M0`. The application instantiates the appropriate class and calls the
+It implements a class for each supported protocol, namely `NEC`, `SONY`, `RC5`
+and `RC6_M0`. The application instantiates the appropriate class and calls the
`transmit` method to send data.
Constructor
is employed by the test script. Must be connected to the IR diode as described
below.
2. `freq=default` The carrier frequency in Hz. The default for NEC is 38000,
- and for Philips is 36000.
+ Sony is 40000 and Philips is 36000.
3. `verbose=False` If `True` emits debug output.
+The `SONY` constructor is of form `pin, bits=12, freq=40000, verbose=False`.
+The `bits` value may be 12, 15 or 20 to set the highest SIRC variant in use.
+Other args are as above. If `bits` is set to 20 then all variants will be
+received. Setting the value to the maximum expected improves error checking and
+timing tolerances. In particular a worst-case 20-bit block takes 39ms nominal,
+yet the repeat time is 45ms nominal.
+
+The Sony remote tested issues both 12 bit and 15 bit streams.
+
Method:
1. `transmit(addr, data, toggle=0)` Integer args. `addr` and `data` are
- normally 8-bit values and `toggle` is 0 or 1.
+ normally 8-bit values and `toggle` is normally 0 or 1.
In the case of NEC, if an address < 256 is passed, normal mode is assumed and
the complementary value is appended. 16-bit values are transmitted as extended
addresses.
In the case of NEC the `toggle` value is ignored. For Philips protocols it
should be toggled each time a button is pressed, and retained if the button is
- held down. The test program illustrates a way to do this.
+ held down. The test program illustrates a way to do this.
+ `SONY` ignores `toggle` unless in 20-bit mode, in which case it is transmitted
+ as the `extended` value and can be any integer in range 0 to 255.
The `transmit` method is synchronous with rapid return. Actual transmission
occurs as a background process, controlled by timers 2 and 5. Execution times
The classes inherit from the abstract base class `IR`. This has an array `.arr`
to contain the duration (in μs) of each carrier on or off period. The
-`transmit` method calls a `tx` method in the subclass which populates this
+`transmit` method calls a `tx` method of the subclass which populates this
array. On completion `transmit` appends a special `STOP` value and initiates
physical transmission which occurs in an interrupt context.
self.edge = 0 # Set up for new data burst and run user callback
self.callback(cmd, addr, 0, *self.args)
+
+class SONY_IR(IR_RX):
+ def __init__(self, pin, callback, bits=20, *args):
+ # 20 bit block has 42 edges and lasts <= 39ms nominal. Add 4ms to time
+ # for tolerances except in 20 bit case where timing is tight with a
+ # repeat period of 45ms.
+ t = int(3 + bits * 1.8) + (1 if bits == 20 else 4)
+ super().__init__(pin, 2 + bits * 2, t, callback, *args)
+ self._addr = 0
+ self._bits = bits
+
+ def decode(self, _):
+ try:
+ nedges = self.edge # No. of edges detected
+ print(nedges)
+ if nedges > 42:
+ raise RuntimeError(OVERRUN)
+ bits = (nedges - 2) // 2
+ if nedges not in (26, 32, 42) or bits > self._bits:
+ raise RuntimeError(BADBLOCK)
+ self.verbose and print('SIRC {}bit'.format(bits))
+ width = ticks_diff(self._times[1], self._times[0])
+ if not 1800 < width < 3000: # 2.4ms leading mark for all valid data
+ raise RuntimeError(BADSTART)
+ width = ticks_diff(self._times[2], self._times[1])
+ if not 350 < width < 1000: # 600μs space
+ raise RuntimeError(BADSTART)
+
+ val = 0 # Data received, LSB 1st
+ x = 2
+ bit = 1
+ while x < nedges - 2:
+ if ticks_diff(self._times[x + 1], self._times[x]) > 900:
+ val |= bit
+ bit <<= 1
+ x += 2
+
+ cmd = val & 0x7f # 7 bit command
+ val >>= 7
+ if nedges < 42:
+ addr = val & 0xff # 5 or 8 bit addr
+ val = 0
+ else:
+ addr = val & 0x1f # 5 bit addr
+ val >>= 5 # 8 bit extended
+ except RuntimeError as e:
+ cmd = e.args[0]
+ addr = 0
+ val = 0
+ self.edge = 0 # Set up for new data burst and run user callback
+ self.callback(cmd, addr, val, *self.args)
+
class RC5_IR(IR_RX):
def __init__(self, pin, callback, *args):
# Block lasts <= 30ms and has <= 28 edges
elif data >= 0:
print('Data {:03x} Addr {:03x} Ctrl {:01x}'.format(data, addr, ctrl))
else:
- print('{} Address: {}'.format(errors[data], hex(addr)))
+ print(errors[data]) # Application would ignore errors
s = '''Test for IR receiver. Run:
-ir_tx_test.test() for NEC protocol,
-ir_tx_test.test(5) for Philips RC-5 protocol,
-ir_tx_test.test(6) for RC6 mode 0.
+from ir_rx_test import test
+test() for NEC protocol,
+test(1) for Sony SIRC 12 bit,
+test(2) for Sony SIRC 15 bit,
+test(3) for Sony SIRC 20 bit,
+test(5) for Philips RC-5 protocol,
+test(6) for RC6 mode 0.
Background processing means REPL prompt reappears.
Hit ctrl-D to stop (soft reset).'''
def test(proto=0):
if proto == 0:
ir = NEC_IR(p, cb) # Extended mode
+ elif proto < 4:
+ bits = (12, 15, 20)[proto - 1]
+ ir = SONY_IR(p, cb, bits)
+ ir.verbose = True
elif proto == 5:
ir = RC5_IR(p, cb)
elif proto == 6:
self.aptr = 0 # Reset pointer
self.cb(self._tim) # Initiate physical transmission.
+# NEC protocol
+class SONY(IR):
+
+ def __init__(self, pin, bits=12, freq=40000, verbose=False): # Sony specifies 40KHz
+ super().__init__(pin, freq, 3 + bits * 2, 30, verbose)
+ if bits not in (12, 15, 20):
+ raise ValueError('bits must be 12, 15 or 20.')
+ self.bits = bits
+
+ def tx(self, addr, data, ext):
+ self.append(2400, 600)
+ bits = self.bits
+ v = data & 0x7f
+ if bits == 12:
+ v |= (addr & 0x1f) << 7
+ elif bits == 15:
+ v |= (addr & 0xff) << 7
+ else:
+ v |= (addr & 0x1f) << 7
+ v |= (ext & 0xff) << 12
+ for _ in range(bits):
+ self.append(1200 if v & 1 else 600, 600)
+ v >>= 1
+
# Philips RC5 protocol
class RC5(IR):
-# ir_tx_test.py Test for nonblocking NEC/RC-5/RC-6 mode 0 IR blaster.
+# ir_tx_test.py Test for nonblocking NEC/SONY/RC-5/RC-6 mode 0 IR blaster.
# Released under the MIT License (MIT). See LICENSE.
# Copyright (c) 2020 Peter Hinch
-# Implements a 2-button remote control on a Pyboard
+# Implements a 2-button remote control on a Pyboard with auto repeat.
from pyb import Pin, LED
import uasyncio as asyncio
from aswitch import Switch, Delay_ms
-from ir_tx import NEC, RC5, RC6_M0
+from ir_tx import NEC, SONY, RC5, RC6_M0
loop = asyncio.get_event_loop()
def cfunc(self): # Button push: send data
self.irb.transmit(self.addr, self.data, Rbutton.toggle)
- # Auto repeat
+ # Auto repeat. The Sony protocol specifies 45ms but this is tight.
+ # In 20 bit mode a data burst can be upto 39ms long.
self.tim.trigger(108)
def ofunc(self): # Button release: cancel repeat timer
irb = NEC(pin) # Default NEC freq == 38KHz
# Option to send REPEAT code. Most remotes do this.
rep_code = True
+ elif proto < 4:
+ bits = (12, 15, 20)[proto - 1]
+ irb = SONY(pin, bits, 38000) # My decoder chip is 38KHz
elif proto == 5:
irb = RC5(pin, 38000) # My decoder chip is 38KHz
elif proto == 6:
led.toggle()
s = '''Test for IR transmitter. Run:
-ir_tx_test.test() for NEC protocol
-ir_tx_test.test(5) for RC-5 protocol
-ir_tx_test.test(6) for RC-6 mode 0.
+from ir_tx_test import test
+test() for NEC protocol
+test(1) for Sony SIRC 12 bit
+test(2) for Sony SIRC 15 bit
+test(3) for Sony SIRC 20 bit
+test(5) for Philips RC-5 protocol
+test(6) for Philips RC-6 mode 0.
Ground X3 to send addr 1 data 7
Ground X4 to send addr 0x10 data 0x0b.'''
projects / micorpython_ir.git / commitdiff