def test_es(self):
edges = [(0.0, 0), (0.5, 1), (2.0, 0), (4.0, 1)]
es = decode.EdgeSequence(iter(edges), 1.0)
self.assertEqual(es.cur_state(), 0)
states = [0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1]
for i, s in zip(xrange(20), states):
es.advance(0.25)
#print('@@@ cs', es.cur_state(), states[i])
self.assertEqual(es.cur_state(), s, 'advance() mismatch')
es = decode.EdgeSequence(iter(edges), 1.0)
states = [1, 0, 1, 1]
i = 0
while not es.at_end():
es.advance_to_edge()
#print('cs', es.cur_state(), es.cur_time)
self.assertEqual(es.cur_state(), states[i],
'advance_to_edge() mismatch')
i += 1
def rc5_decode(ir_stream, carrier_freq=36.0e3, polarity=ir.IRConfig.IdleLow, logic_levels=None, \
stream_type=stream.StreamType.Samples):
'''Decode RC5 infrared protocol
This is a generator function that can be used in a pipeline of waveform
procesing operations.
ir_stream (iterable of SampleChunk objects or (float, int) pairs)
A sample stream or edge stream of IR pulses. The type of stream is identified
by the stream_type parameter. When this is a sample stream, an initial block
of data is consumed to determine the most likely logic levels in the signal.
This signal can be either modulated or demodulated.
carrier_freq (float)
The carrier frequency for modulation.
polarity (infrared.IRConfig)
Set the polarity (idle state high or low).
logic_levels ((float, float) or None)
Optional pair that indicates (low, high) logic levels of the sample
stream. When present, auto level detection is disabled. This has no effect on
edge streams.
stream_type (streaming.StreamType)
A StreamType value indicating that the ir_stream parameter represents either Samples
or Edges.
Yields a series of RC5StreamMessage objects.
Raises AutoLevelError if stream_type = Samples and the logic levels cannot
be determined.
'''
if stream_type == stream.StreamType.Samples:
if logic_levels is None:
samp_it, logic_levels = decode.check_logic_levels(ir_stream)
else:
samp_it = ir_stream
edges = decode.find_edges(samp_it, logic_levels, hysteresis=0.4)
else: # the stream is already a list of edges
edges = ir_stream
# Demodulate signal (also passes an unmodulated signal without changes)
edges = ir.demodulate(edges, carrier_freq, polarity)
pulse_width = 889.0e-6 # 889us pulse width
es = decode.EdgeSequence(edges, pulse_width)
while not es.at_end():
# Look for the rising edge of a pulse
if es.cur_state() == 0:
es.advance_to_edge() # Now we're 1
msg_start_time = es.cur_time - pulse_width
# Move ahead half a pulse and check that we are still 1
es.advance(pulse_width / 2.0)
if es.cur_state() != 1:
continue
# Advance through edge sequence recording state until we see 3 0's or 3 1's in a row
# This indicates a break in the Manchester encoding.
coded_bits = [0, 1]
bit_starts = [0.0, 0.0]
same_count = 1
prev_state = 1
while True:
es.advance()
coded_bits.append(es.cur_state())
bit_starts.append(es.cur_time - pulse_width / 2.0)
if es.cur_state() == prev_state:
same_count += 1
else:
same_count = 1
if same_count > 2:
break
prev_state = es.cur_state()
msg_end_time = es.cur_time - pulse_width
if len(coded_bits) >= 14 * 2:
# Decode Manchester
# The second bit of each pair is the same as the decoded bit
msg_bits = coded_bits[1:28:2]
mb_starts = bit_starts[::2]
#print('$$$ coded_bits:', coded_bits)
#print('$$$ msg_bits:', msg_bits)
toggle = msg_bits[2]
addr = join_bits(msg_bits[3:8])
cmd = join_bits([0 if msg_bits[1] else 1] + msg_bits[8:14])
msg = RC5Message(cmd, addr, toggle)
sm = RC5StreamMessage((msg_start_time, msg_end_time), msg)
sm.annotate('frame', {'name': 'frame'},
stream.AnnotationFormat.Hidden)
sm.subrecords.append(
stream.StreamSegment((mb_starts[2], mb_starts[3]),
toggle,
kind='toggle'))
sm.subrecords[-1].annotate('data', {'_bits': 1},
stream.AnnotationFormat.Int)
sm.subrecords.append(
stream.StreamSegment((mb_starts[3], mb_starts[8]),
addr,
kind='addr'))
sm.subrecords[-1].annotate('addr', {'_bits': 5})
sm.subrecords.append(
stream.StreamSegment((mb_starts[8], mb_starts[14]),
cmd,
kind='cmd'))
sm.subrecords[-1].annotate('data', {'_bits': 6})
if cmd > 63:
# Extended format; 7-th bit is just after first start bit
sm.subrecords[-1].fields['_bits'] = 7
sm.subrecords.append(
stream.StreamSegment((mb_starts[1], mb_starts[2]),
msg_bits[1],
kind='cmd bit-7'))
sm.subrecords[-1].annotate('data1', {'_bits': 1},
stream.AnnotationFormat.Int)
yield sm
def rc6_decode(ir_stream, carrier_freq=36.0e3, polarity=ir.IRConfig.IdleLow, logic_levels=None, \
stream_type=stream.StreamType.Samples):
'''Decode RC6 infrared protocol
This is a generator function that can be used in a pipeline of waveform
procesing operations.
ir_stream (iterable of SampleChunk objects or (float, int) pairs)
A sample stream or edge stream of IR pulses. The type of stream is identified
by the stream_type parameter. When this is a sample stream, an initial block
of data is consumed to determine the most likely logic levels in the signal.
This signal can be either modulated or demodulated.
carrier_freq (float)
The carrier frequency for modulation.
polarity (infrared.IRConfig)
Set the polarity (idle state high or low).
logic_levels ((float, float) or None)
Optional pair that indicates (low, high) logic levels of the sample
stream. When present, auto level detection is disabled. This has no effect on
edge streams.
stream_type (streaming.StreamType)
A StreamType value indicating that the ir_stream parameter represents either Samples
or Edges.
Yields a series of RC6StreamMessage objects.
Raises AutoLevelError if stream_type = Samples and the logic levels cannot
be determined.
'''
if stream_type == stream.StreamType.Samples:
if logic_levels is None:
samp_it, logic_levels = decode.check_logic_levels(ir_stream)
else:
samp_it = ir_stream
edges = decode.find_edges(samp_it, logic_levels, hysteresis=0.4)
else: # the stream is already a list of edges
edges = ir_stream
# Demodulate signal (also passes an unmodulated signal without changes)
edges = ir.demodulate(edges, carrier_freq, polarity)
pulse_width = 444.0e-6 # 444us pulse width
es = decode.EdgeSequence(edges, pulse_width)
epsilon = 30.0e-6 # allow +/-30us variation for pulses and bit times
time_is_nearly = functools.partial(ir.time_is_nearly, epsilon=epsilon)
while not es.at_end():
# Look for the rising edge of a pulse
if es.cur_state() == 0:
es.advance_to_edge() # Now we're 1
msg_start_time = es.cur_time
ts = es.advance_to_edge()
if not time_is_nearly(ts, 6 * pulse_width):
continue # This is not the leading AGC pulse of a message
ts = es.advance_to_edge()
if not time_is_nearly(ts, 2 * pulse_width):
continue # This is not the leading AGC pulse of a message
# Move ahead half a pulse and check that we are still 1
es.advance(pulse_width / 2.0)
if es.cur_state() != 1:
continue # Not a valid start bit
es.advance() # End of start bit
# Advance through edge sequence recording state until we see 4 0's or 4 1's in a row
# This indicates a break in the Manchester encoding.
coded_bits = [1, 0] # Start bit
bit_starts = [0.0, 0.0]
same_count = 1
prev_state = 1
while True:
es.advance()
coded_bits.append(es.cur_state())
bit_starts.append(es.cur_time - pulse_width / 2.0)
if es.cur_state() == prev_state:
same_count += 1
else:
same_count = 1
if same_count > 3:
break
prev_state = es.cur_state()
msg_end_time = es.cur_time - 2.5 * pulse_width
#print('$$$ found bits:', len(coded_bits))
if len(coded_bits) >= 22 * 2:
# Decode Manchester
# The first bit of each pair is the same as the decoded bit
msg_bits = coded_bits[0:44:2]
mb_starts = bit_starts[::2]
mode = join_bits(msg_bits[1:4])
toggle = msg_bits[4]
if mode == 6: # RC6A message
if msg_bits[6]: # 15-bit customer field
msg_bits = coded_bits[0:76:2]
customer = join_bits(msg_bits[7:22])
asb = 22 # addr start bit index
else: # 7-bit customer field
msg_bits = coded_bits[0:60:2]
customer = join_bits(msg_bits[7:14])
asb = 14
else: # RC6 message
customer = None
asb = 6
#print('$$$ coded_bits:', coded_bits)
#print('$$$ msg_bits:', msg_bits)
addr = join_bits(msg_bits[asb:asb+8])
cmd = join_bits(msg_bits[asb+8:asb+16])
msg = RC6Message(cmd, addr, toggle, mode, customer)
sm = RC6StreamMessage((msg_start_time, msg_end_time), msg)
sm.annotate('frame', {'name':'frame'}, stream.AnnotationFormat.Hidden)
sm.subrecords.append(stream.StreamSegment((mb_starts[1], mb_starts[4]), mode, kind='mode'))
sm.subrecords[-1].annotate('addr', {'_bits':3})
sm.subrecords.append(stream.StreamSegment((mb_starts[4], mb_starts[6]), toggle, kind='toggle'))
sm.subrecords[-1].annotate('data', {'_bits':1}, stream.AnnotationFormat.Int)
if mode == 6:
sm.subrecords.append(stream.StreamSegment((mb_starts[6], mb_starts[asb]), customer, kind='customer'))
sm.subrecords[-1].annotate('data', {'_bits':7 + msg_bits[6]*8})
sm.subrecords.append(stream.StreamSegment((mb_starts[asb], mb_starts[asb+8]), addr, kind='addr'))
sm.subrecords[-1].annotate('addr', {'_bits':8})
sm.subrecords.append(stream.StreamSegment((mb_starts[asb+8], mb_starts[asb+16]), cmd, kind='cmd'))
sm.subrecords[-1].annotate('data', {'_bits':8})
yield sm
def j1850_pwm_decode(pwm,
logic_levels=None,
stream_type=stream.StreamType.Samples):
'''Decode a J1850 PWM data stream
This decodes the Pulse Width Modulated version of J1850 (Ford).
This is a generator function that can be used in a pipeline of waveform
procesing operations.
Sample streams are a sequence of SampleChunk Objects. Edge streams are a sequence
of 2-tuples of (time, int) pairs. The type of stream is identified by the stream_type
parameter. Sample streams will be analyzed to find edge transitions representing
0 and 1 logic states of the waveforms. With sample streams, an initial block of data
is consumed to determine the most likely logic levels in the signal.
pwm (iterable of SampleChunk objects or (float, int) pairs)
A sample stream or edge stream representing a PWM Bus+ signal or the differential
Bus+ - Bus-.
logic_levels ((float, float) or None)
Optional pair that indicates (low, high) logic levels of the sample
stream. When present, auto level detection is disabled. This has no effect on
edge streams.
stream_type (streaming.StreamType)
A StreamType value indicating that the can parameter represents either Samples
or Edges
Yields a series of J1850StreamFrame objects. Each frame contains subrecords marking the location
of sub-elements within the frame. CRC errors are recorded as an error status in their
respective subrecords.
Raises AutoLevelError if stream_type = Samples and the logic levels cannot
be determined.
'''
if stream_type == stream.StreamType.Samples:
if logic_levels is None:
pwm_it, logic_levels = decode.check_logic_levels(pwm)
else:
pwm_it = pwm
edges = decode.find_edges(pwm_it, logic_levels, hysteresis=0.4)
else: # The stream is already a list of edges
edges = pwm
es = decode.EdgeSequence(edges, 0.0)
while not es.at_end():
# Look for start of frame
es.advance_to_edge()
if es.cur_state() != 1: continue
frame_start = es.cur_time
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
if 27.0e-6 <= pulse_width <= 34.0e-6: # This is a valid SOF pulse (Tp7)
sof_start = es.cur_time
es.advance_to_edge() # Move to end of SOF pulse
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
if 42.0e-6 <= es.cur_time - sof_start + pulse_width <= 54.0e-6:
# Valid SOF (Tp4)
es.advance_to_edge() # Move to first bit
else: # Look for break condition
if 34.0e-6 < pulse_width <= 43.0e-6 and es.cur_state() == 1:
brk = J1850Break()
sf = stream.StreamSegment((es.cur_time, es.next_states[0]),
brk,
kind='break')
sf.annotate('frame', {'value': 'Break'},
stream.AnnotationFormat.String)
yield sf
continue
def collect_bits(es):
'''Find frame and IFR bits'''
frame_bits = []
bit_starts = []
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
while pulse_width <= 18.0e-6:
if 4.0e-6 <= pulse_width <= 18.0e-6:
if pulse_width <= 10.0e-6:
b = 1
else:
b = 0
frame_bits.append(b)
bit_starts.append(es.cur_time)
bit_pulse = pulse_width
# Move to end of pulse
es.advance_to_edge()
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
tp3 = bit_pulse + pulse_width
if 21.0e-6 <= tp3 <= 27e-6: # Valid bit
es.advance_to_edge() # Move to start of next bit
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
else: # No more bits
break
else: # Invalid pulse < 4us
break
bit_starts.append(es.cur_time)
return (frame_bits, bit_starts, pulse_width)
# Get the frame bits
frame_bits, bit_starts, pulse_width = collect_bits(es)
if 34.0e-6 < pulse_width <= 43.0e-6 and es.cur_state() == 1:
brk = J1850Break()
sf = stream.StreamSegment((es.cur_time, es.next_states[0]),
brk,
kind='break')
sf.annotate('frame', {'value': 'Break'},
stream.AnnotationFormat.String)
yield sf
continue
# Validate collected bits
if len(frame_bits) % 8 != 0 or len(frame_bits) < 2 * 8:
continue
# Convert frame bits to bytes
bytes = []
for i in xrange(len(frame_bits) // 8):
bytes.append(join_bits(frame_bits[i * 8:i * 8 + 8]))
byte_starts = bit_starts[::8]
header_len = 1 if bytes[0] & 0x10 else 3
if header_len == 3 and len(bytes) < 4: continue
priority = bytes[0] >> 5
msg_type = bytes[0] & 0x0F
data = bytes[header_len:-1]
if len(data) == 0: data = None
# Look for IFR
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
ifr_bytes = []
ifr_byte_starts = []
ifr_with_crc = False
if 42.0e-6 <= pulse_width + (es.cur_time - bit_starts[-2]
) <= 63.0e-6 and (msg_type & 0x08) == 0:
# IFR is present
es.advance_to_edge() # Start of first IFR bit
ifr_with_crc = True if msg_type == J1850MT.FunctionRead else False
# Get the IFR bits
ifr_bits, ifr_bit_starts, pulse_width = collect_bits(es)
if 34.0e-6 < pulse_width <= 43.0e-6 and es.cur_state() == 1:
brk = J1850Break()
sf = stream.StreamSegment((es.cur_time, es.next_states[0]),
brk,
kind='break')
sf.annotate('frame', {'value': 'Break'},
stream.AnnotationFormat.String)
yield sf
continue
# Validate IFR bits
if len(ifr_bits) % 8 == 0 and len(ifr_bits) >= 8:
# Convert IFR bits to bytes
for i in xrange(len(ifr_bits) // 8):
ifr_bytes.append(join_bits(ifr_bits[i * 8:i * 8 + 8]))
ifr_byte_starts = ifr_bit_starts[::8]
sf = _build_j1850_record(bytes, ifr_bytes, byte_starts, ifr_byte_starts, ifr_with_crc, \
(frame_start, es.cur_time + 4.0e-6))
yield sf
def j1850_vpw_decode(vpw,
norm_bit=VPWNormBitStyle.SAE,
logic_levels=None,
stream_type=stream.StreamType.Samples):
'''Decode a J1850 VPW data stream
This decodes the Variable Pulse Width version of J1850 (GM & Chrysler).
This is a generator function that can be used in a pipeline of waveform
procesing operations.
Sample streams are a sequence of SampleChunk Objects. Edge streams are a sequence
of 2-tuples of (time, int) pairs. The type of stream is identified by the stream_type
parameter. Sample streams will be analyzed to find edge transitions representing
0 and 1 logic states of the waveforms. With sample streams, an initial block of data
is consumed to determine the most likely logic levels in the signal.
vpw (iterable of SampleChunk objects or (float, int) pairs)
A sample stream or edge stream representing a VPW data signal.
norm_bit (VPWNormBitStyle)
How to interpret the normalization bit for In-Frame Response. Either standard SAE
style or the GM specific variant. This determines whether the IFR is expected to
have a CRC independently from the message type.
logic_levels ((float, float) or None)
Optional pair that indicates (low, high) logic levels of the sample
stream. When present, auto level detection is disabled. This has no effect on
edge streams.
stream_type (streaming.StreamType)
A StreamType value indicating that the can parameter represents either Samples
or Edges
Yields a series of J1850StreamFrame objects. Each frame contains subrecords marking the location
of sub-elements within the frame. CRC errors are recorded as an error status in their
respective subrecords.
Raises AutoLevelError if stream_type = Samples and the logic levels cannot
be determined.
'''
if stream_type == stream.StreamType.Samples:
if logic_levels is None:
vpw_it, logic_levels = decode.check_logic_levels(vpw)
else:
vpw_it = vpw
edges = decode.find_edges(vpw_it, logic_levels, hysteresis=0.4)
else: # The stream is already a list of edges
edges = vpw
es = decode.EdgeSequence(edges, 0.0)
while not es.at_end():
# Look for start of frame
es.advance_to_edge()
if es.cur_state() != 1: continue
frame_start = es.cur_time
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
if 163.0e-6 < pulse_width <= 239.0e-6: # This is a valid SOF
es.advance_to_edge() # Move to first bit
else:
if pulse_width > 280.0e-6 and es.cur_state() == 1:
brk = J1850Break()
sf = stream.StreamSegment((es.cur_time, es.next_states[0]),
brk,
kind='break')
sf.annotate('frame', {'value': 'Break'},
stream.AnnotationFormat.String)
yield sf
continue
def collect_bits(es):
'''Find frame and IFR bits'''
frame_bits = []
bit_starts = []
is_passive = 1
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
while pulse_width <= 239.0e-6:
if 34.0e-6 < pulse_width <= 163.0e-6:
if pulse_width > 96.0e-6: # 128us pulse
b = 1 if is_passive else 0
else: # 64us pulse
b = 0 if is_passive else 1
frame_bits.append(b)
bit_starts.append(es.cur_time)
is_passive = 1 - is_passive
elif pulse_width > 163.0e-6: # EOD
break
else: # Invalid pulse < 34us
break
es.advance_to_edge()
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
bit_starts.append(es.cur_time)
return (frame_bits, bit_starts, pulse_width)
# Get the frame bits
frame_bits, bit_starts, pulse_width = collect_bits(es)
if pulse_width > 280.0e-6 and es.cur_state() == 1:
brk = J1850Break()
sf = stream.StreamSegment((es.cur_time, es.next_states[0]),
brk,
kind='break')
sf.annotate('frame', {'value': 'Break'},
stream.AnnotationFormat.String)
yield sf
continue
# Validate collected bits
if len(frame_bits) % 8 != 0 or len(frame_bits) < 2 * 8:
continue
# Convert frame bits to bytes
bytes = []
for i in xrange(len(frame_bits) // 8):
bytes.append(join_bits(frame_bits[i * 8:i * 8 + 8]))
byte_starts = bit_starts[::8]
header_len = 1 if bytes[0] & 0x10 else 3
if header_len == 3 and len(bytes) < 4: continue
priority = bytes[0] >> 5
msg_type = bytes[0] & 0x0F
data = bytes[header_len:-1]
if len(data) == 0: data = None
# Look for IFR
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
ifr_bytes = []
ifr_byte_starts = []
ifr_with_crc = False
if 200.0e-6 < pulse_width <= 280.0e-6 and (msg_type & 0x08) == 0:
# IFR is present
# Check normalization bit width to determine if IFR CRC is present
es.advance_to_edge() # Start of norm bit
if es.next_states[0] > es.cur_time:
pulse_width = es.next_states[0] - es.cur_time
else:
pulse_width = 500.0e-6
if norm_bit == VPWNormBitStyle.SAE:
ifr_with_crc = True if pulse_width > 96.0e-6 else False
else: # GM
ifr_with_crc = True if pulse_width <= 96.0e-6 else False
es.advance_to_edge() # Move to first bit
# Get the IFR bits
ifr_bits, ifr_bit_starts, pulse_width = collect_bits(es)
if pulse_width > 280.0e-6 and es.cur_state() == 1:
brk = J1850Break()
sf = stream.StreamSegment((es.cur_time, es.next_states[0]),
brk,
kind='break')
sf.annotate('frame', {'value': 'Break'},
stream.AnnotationFormat.String)
yield sf
continue
# Validate IFR bits
if len(ifr_bits) % 8 == 0 and len(ifr_bits) >= 8:
# Convert IFR bits to bytes
for i in xrange(len(ifr_bits) // 8):
ifr_bytes.append(join_bits(ifr_bits[i * 8:i * 8 + 8]))
ifr_byte_starts = ifr_bit_starts[::8]
sf = _build_j1850_record(bytes, ifr_bytes, byte_starts,
ifr_byte_starts, ifr_with_crc,
(frame_start, es.cur_time + 64.0e-6))
yield sf
def sirc_decode(ir_stream, carrier_freq=40.0e3, polarity=ir.IRConfig.IdleLow, logic_levels=None, \
stream_type=stream.StreamType.Samples):
'''Decode Sony SIRC infrared protocol
This is a generator function that can be used in a pipeline of waveform
procesing operations.
ir_stream (iterable of SampleChunk objects or (float, int) pairs)
A sample stream or edge stream of IR pulses. The type of stream is identified
by the stream_type parameter. When this is a sample stream, an initial block
of data is consumed to determine the most likely logic levels in the signal.
This signal can be either modulated or demodulated.
carrier_freq (float)
The carrier frequency for modulation.
polarity (infrared.IRConfig)
Set the polarity (idle state high or low).
logic_levels ((float, float) or None)
Optional pair that indicates (low, high) logic levels of the sample
stream. When present, auto level detection is disabled. This has no effect on
edge streams.
stream_type (streaming.StreamType)
A StreamType value indicating that the ir_stream parameter represents either Samples
or Edges.
Yields a series of SIRCStreamMessage objects.
Raises AutoLevelError if stream_type = Samples and the logic levels cannot
be determined.
'''
if stream_type == stream.StreamType.Samples:
if logic_levels is None:
samp_it, logic_levels = decode.check_logic_levels(ir_stream)
else:
samp_it = ir_stream
edges = decode.find_edges(samp_it, logic_levels, hysteresis=0.4)
else: # the stream is already a list of edges
edges = ir_stream
# Demodulate signal (also passes an unmodulated signal without changes)
edges = ir.demodulate(edges, carrier_freq, polarity)
mod_period = (1.0 / carrier_freq) # Not really important. Just need a default value to pass to EdgeSequence
es = decode.EdgeSequence(edges, mod_period)
epsilon = 30.0e-6 # allow +/-30us variation for pulses and bit times
time_is_nearly = functools.partial(ir.time_is_nearly, epsilon=epsilon)
one_t = 600.0e-6 # 600us 1T time
while not es.at_end():
# Look for the falling edge of a start pulse
if es.cur_state() == 0:
es.advance_to_edge() # Now we're 1
ts = es.advance_to_edge() # Now we're 0. Could be end of start pulse
# Measure the time we skipped forward by
if not time_is_nearly(ts, 4 * one_t):
continue # Not a start pulse
msg_start_time = es.cur_time - ts
msg_bits = []
bit_starts = []
prev_edge = 0.0
# Accumulate bits until idle for too long
while True:
prev_edge = es.cur_time
ts = es.advance_to_edge()
if not time_is_nearly(ts, one_t):
break # Not the beginning of a bit
bit_starts.append(es.cur_time - ts)
ts = es.advance_to_edge()
if time_is_nearly(ts, one_t): # 0-bit
msg_bits.append(0)
elif time_is_nearly(ts, 2 * one_t): #1-bit
msg_bits.append(1)
else:
break
bit_starts.append(prev_edge) # End of last bit
#print('### last bit:', es.cur_time)
if len(msg_bits) in (12, 15, 20):
cmd = join_bits(reversed(msg_bits[0:7]))
cmd_range = (bit_starts[0], bit_starts[7])
if len(msg_bits) == 12 or len(msg_bits) == 20:
device = join_bits(reversed(msg_bits[7:12]))
device_range = (bit_starts[7], bit_starts[12])
else: # 15-bit command
device = join_bits(reversed(msg_bits[7:15]))
device_range = (bit_starts[7], bit_starts[15])
extended = None
if len(msg_bits) == 20: # 20-bit extended format
extended = join_bits(reversed(msg_bits[12:20]))
extended_range = (bit_starts[12], bit_starts[20])
msg = SIRCMessage(cmd, device, extended)
sm = SIRCStreamMessage((msg_start_time, prev_edge + 0.5*one_t), msg)
sm.annotate('frame', {}, stream.AnnotationFormat.Hidden)
cmd_ss = stream.StreamSegment((cmd_range[0], cmd_range[1]), cmd, kind='command')
sm.subrecords.append(cmd_ss)
sm.subrecords[-1].annotate('data', {'_bits':7})
dev_ss = stream.StreamSegment((device_range[0], device_range[1]), device, kind='device')
sm.subrecords.append(dev_ss)
sm.subrecords[-1].annotate('addr')
if len(msg_bits) == 15:
sm.subrecords[-1].fields['_bits'] = 8
else:
sm.subrecords[-1].fields['_bits'] = 5
if extended is not None:
ext_ss = stream.StreamSegment((extended_range[0], extended_range[1]), extended, kind='extended')
sm.subrecords.append(ext_ss)
sm.subrecords[-1].annotate('data', {'_bits':8})
yield sm
def manchester_decode(edges, bit_period, falling=0, combine_bits=False):
'''Convert differential coded edges to manchester states
edges (iterable of (float, int))
An edge stream of differential states (-1, 0, 1) representing Manchester
coded bits.
bit_period (float)
The period of a single bit.
falling (int)
The bit encoding for a falling edge. Either 0 or 1.
combine_bits (bool)
When True, the output states will only be yielded when a different state
occurs. When False, a state is yielded for each bit or half-bit.
Yields a stream of Manchester states in (float, int) form.
'''
def to_manchester(diff_state):
'''Utility function to convert differentially coded states to ManchesterStates'''
if diff_state == 1:
mstate = ManchesterStates.High
elif diff_state == -1:
mstate = ManchesterStates.Low
else:
mstate = ManchesterStates.Idle
return mstate
es = decode.EdgeSequence(edges, bit_period)
# Initial state
yield (es.cur_time, to_manchester(es.cur_state()))
processing_bits = False
prev_bit = None
while not es.at_end():
if not processing_bits: #state == S_IDLE:
es.advance_to_edge()
if es.cur_state() in (1, -1):
es.advance(bit_period * 0.25)
processing_bits = True
prev_bit = None
else:
yield (es.cur_time, ManchesterStates.Idle)
else: # processing bits
if es.cur_state() not in (1, -1): # Idle
yield (es.cur_time - bit_period*0.25, ManchesterStates.Idle)
processing_bits = False
elif es.next_states[0] - es.cur_time < bit_period * 0.5: # This is a bit
if es.next_states[1] == 1: # rising edge
bit = 1 - falling
elif es.next_states[1] == -1: # falling edge
bit = falling
else: # Unexpected transition to idle
# Create a half bit for this segment
yield (es.cur_time - bit_period*0.25, to_manchester(es.cur_state()))
es.advance(bit_period * 0.5)
continue
#print('### got bit 2:', bit, prev_bit, es.cur_time - bit_period*0.25)
if not combine_bits or bit != prev_bit:
yield (es.cur_time - bit_period*0.25, bit)
prev_bit = bit
es.advance(es.next_states[0] - es.cur_time + bit_period*0.75) # Resync to next edge
else: # This is a half bit
#print('## half bit 2', es.cur_time - bit_period*0.25)
half_bit = to_manchester(es.cur_state())
if not combine_bits or half_bit != prev_bit:
yield (es.cur_time - bit_period*0.25, half_bit)
prev_bit = half_bit
es.advance(bit_period * 0.5)
def nec_decode(ir_stream, carrier_freq=38.0e3, polarity=ir.IRConfig.IdleLow, logic_levels=None, \
stream_type=stream.StreamType.Samples):
'''Decode NEC infrared protocol
This is a generator function that can be used in a pipeline of waveform
procesing operations.
ir_stream (iterable of SampleChunk objects or (float, int) pairs)
A sample stream or edge stream of IR pulses. The type of stream is identified
by the stream_type parameter. When this is a sample stream, an initial block
of data is consumed to determine the most likely logic levels in the signal.
This signal can be either modulated or demodulated.
carrier_freq (float)
The carrier frequency for modulation.
polarity (infrared.IRConfig)
Set the polarity (idle state high or low).
logic_levels ((float, float) or None)
Optional pair that indicates (low, high) logic levels of the sample
stream. When present, auto level detection is disabled. This has no effect on
edge streams.
stream_type (streaming.StreamType)
A StreamType value indicating that the ir_stream parameter represents either Samples
or Edges.
Yields a series of NECStreamMessage objects.
Raises AutoLevelError if stream_type = Samples and the logic levels cannot
be determined.
'''
if stream_type == stream.StreamType.Samples:
if logic_levels is None:
samp_it, logic_levels = decode.check_logic_levels(ir_stream)
else:
samp_it = ir_stream
edges = decode.find_edges(samp_it, logic_levels, hysteresis=0.4)
else: # the stream is already a list of edges
edges = ir_stream
# Demodulate signal (also passes an unmodulated signal without changes)
edges = ir.demodulate(edges, carrier_freq, polarity)
mod_period = (
1.0 / carrier_freq
) # Not really important. Just need a default value to pass to EdgeSequence
es = decode.EdgeSequence(edges, mod_period)
epsilon = 30.0e-6 # Allow +/-30us variation for pulses and bit times
time_is_nearly = functools.partial(ir.time_is_nearly, epsilon=epsilon)
time_is_at_least = functools.partial(ir.time_is_at_least, epsilon=epsilon)
while not es.at_end():
# Look for the falling edge of an AGC burst
if es.cur_state() == 0:
es.advance_to_edge() # Now we're 1
es.advance_to_edge() # Now we're 0. Could be end of AGC
ts = es.advance_to_edge() # Start of next pulse
# Measure the time we skipped forward by
if time_is_nearly(ts, 2.25e-3) or time_is_nearly(ts, 4.5e-3):
# Previous pulse was AGC (gap between 2.25ms and 4.5ms)
msg_start_time = es.cur_time - ts - 9.0e-3
if time_is_at_least(ts, 4.5e-3): # command message
msg_bits = []
bit_starts = []
while len(msg_bits) < 32:
bit_start_time = es.cur_time
ts = es.advance_to_edge()
if time_is_nearly(ts, 560.0e-6): # 560us bit pulse time
# Measure next time gap to determine if bit is 1 or 0
ts = es.advance_to_edge()
bit_period = es.cur_time - bit_start_time
if time_is_nearly(bit_period, 2.25e-3): # 1-bit
msg_bits.append(1)
bit_starts.append(bit_start_time)
if time_is_nearly(bit_period, 1.12e-3): # 0-bit
msg_bits.append(0)
bit_starts.append(bit_start_time)
else:
break
if len(msg_bits) == 32:
bit_starts.append(es.cur_time) # End of last byte
# Check for the stop bit
ts = es.advance_to_edge()
if time_is_nearly(ts, 560.0e-6): # 560us stop pulse time
# Valid command message
msg_bytes = [
join_bits(reversed(msg_bits[i:i + 8]))
for i in xrange(0, 32, 8)
]
m_bounds = [(bit_starts[i], bit_starts[i + 8])
for i in xrange(0, 32, 8)]
addr_low = msg_bytes[0]
addr_high = msg_bytes[1]
cmd = msg_bytes[2]
cmd_inv = msg_bytes[3]
nec_msg = NECMessage(cmd, addr_low, addr_high, cmd_inv)
sm = NECStreamMessage((msg_start_time, es.cur_time),
nec_msg)
sm.annotate('frame', {},
stream.AnnotationFormat.Hidden)
sm.subrecords.append(
stream.StreamSegment(
(m_bounds[0][0], m_bounds[0][1]),
addr_low,
kind='addr-low'))
sm.subrecords[-1].annotate('addr', {'_bits': 8})
sm.subrecords.append(
stream.StreamSegment(
(m_bounds[1][0], m_bounds[1][1]),
addr_high,
kind='addr-high'))
sm.subrecords[-1].annotate('addr', {'_bits': 8})
sm.subrecords.append(
stream.StreamSegment(
(m_bounds[2][0], m_bounds[2][1]),
cmd,
kind='cmd'))
sm.subrecords[-1].annotate('data', {'_bits': 8})
status = stream.StreamStatus.Ok if cmd == (
~cmd_inv) & 0xFF else stream.StreamStatus.Error
sm.subrecords.append(
stream.StreamSegment(
(m_bounds[3][0], m_bounds[3][1]),
cmd_inv,
kind='cmd-inv',
status=status))
sm.subrecords[-1].annotate('check', {'_bits': 8})
yield sm
else: # repeat message
# Check for the stop bit
ts = es.advance_to_edge()
if time_is_nearly(ts, 560.0e-6): # 560us stop pulse time
# Valid repeat message
sm = NECStreamMessage((msg_start_time, es.cur_time),
NECRepeat())
sm.annotate('frame', {'name': ''},
stream.AnnotationFormat.String)
yield sm