--- /dev/null
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2018 Steve R <steversig@virginmedia.com>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+import sigrokdecode as srd
+
+'''
+OUTPUT_PYTHON format:
+Samples: The Samples array is sent when a DECODE_TIMEOUT occurs.
+[<start>, <finish>, <state>]
+<start> is the sample number of the start of the decoded bit. This may not line
+up with the pulses that were converted into the decoded bit particularly for
+Manchester encoding.
+<finish> is the sample number of the end of the decoded bit.
+<state> is a single character string which is the state of the decoded bit.
+This can be
+'0' zero or low
+'1' one or high
+'E' Error or invalid. This can be caused by missing transitions or the wrong
+pulse lengths according to the rules for the particular encoding. In some cases
+this is intentional (Oregon 1 preamble) and is part of the sync pattern. In
+other cases the signal could simply be broken.
+
+If there are more than self.max_errors (default 5) in decoding then the
+OUTPUT_PYTHON is not sent as the data is assumed to be worthless.
+There also needs to be a low for five times the preamble period at the end of
+each set of pulses to trigger a DECODE_TIMEOUT and get the OUTPUT_PYTHON sent.
+'''
+
+class SamplerateError(Exception):
+ pass
+
+class Decoder(srd.Decoder):
+ api_version = 3
+ id = 'ook'
+ name = 'OOK'
+ longname = 'On-off keying'
+ desc = 'On-off keying protocol.'
+ license = 'gplv2+'
+ inputs = ['logic']
+ outputs = ['ook']
+ channels = (
+ {'id': 'data', 'name': 'Data', 'desc': 'Data line'},
+ )
+ annotations = (
+ ('frame', 'Frame'),
+ ('info', 'Info'),
+ ('1111', '1111'),
+ ('1010', '1010'),
+ ('diffman', 'Diff Man'),
+ ('nrz', 'NRZ'),
+ )
+ annotation_rows = (
+ ('frame', 'Framing',(0,)),
+ ('info', 'Info', (1,)),
+ ('man1111', 'Man 1111', (2,)),
+ ('man1010', 'Man 1010', (3,)),
+ ('diffman', 'Diff Man', (4,)),
+ ('nrz', 'NRZ', (5,)),
+ )
+ binary = (
+ ('pulse-lengths', 'Pulse lengths'),
+ )
+ options = (
+ {'id': 'invert', 'desc': 'Invert data', 'default': 'no',
+ 'values': ('no', 'yes')},
+ {'id': 'decodeas', 'desc': 'Decode type', 'default': 'Manchester',
+ 'values': ('NRZ', 'Manchester', 'Diff Manchester')},
+ {'id': 'preamble', 'desc': 'Preamble', 'default': 'auto',
+ 'values': ('auto', '1010', '1111')},
+ {'id': 'preamlen', 'desc': 'Filter length', 'default': '7',
+ 'values': ('0', '3', '4', '5', '6', '7', '8', '9', '10')},
+ {'id': 'diffmanvar', 'desc': 'Transition at start', 'default': '1',
+ 'values': ('1', '0')},
+ )
+
+ def __init__(self):
+ self.reset()
+
+ def reset(self):
+ self.samplerate = None
+ self.ss = self.es = -1
+ self.ss_1111 = self.ss_1010 = -1
+ self.samplenumber_last = None
+ self.sample_first = None
+ self.sample_high = 0
+ self.sample_low = 0
+ self.edge_count = 0
+ self.word_first = None
+ self.word_count = 0
+ self.state = 'IDLE'
+ self.lstate = None
+ self.lstate_1010 = None
+ self.insync = 0 # Preamble in sync flag
+ self.man_errors = 0
+ self.man_errors_1010 = 0
+ self.preamble = [] # Preamble buffer
+ self.half_time = -1 # Half time for man 1111
+ self.half_time_1010 = 0 # Half time for man 1010
+ self.pulse_lengths = [] # Pulse lengths
+ self.decoded = [] # Decoded stream
+ self.decoded_1010 = [] # Decoded stream
+ self.diff_man_trans = '0' # Transition
+ self.diff_man_len = 1 # Length of pulse in half clock periods
+ self.max_errors = 5 # Max number of errors to output OOK
+
+ def metadata(self, key, value):
+ if key == srd.SRD_CONF_SAMPLERATE:
+ self.samplerate = value
+
+ def start(self):
+ self.out_ann = self.register(srd.OUTPUT_ANN)
+ self.out_python = self.register(srd.OUTPUT_PYTHON)
+ self.out_binary = self.register(srd.OUTPUT_BINARY)
+ self.invert = self.options['invert']
+ self.decodeas = self.options['decodeas']
+ self.preamble_val = self.options['preamble']
+ self.preamble_len = self.options['preamlen']
+ self.diffmanvar = self.options['diffmanvar']
+
+ def putx(self, data):
+ self.put(self.ss, self.es, self.out_ann, data)
+
+ def putp(self, data):
+ self.put(self.ss, self.es, self.out_python, data)
+
+ def dump_pulse_lengths(self):
+ if self.samplerate:
+ self.pulse_lengths[-1] = self.sample_first # Fix final pulse length.
+ mystring = 'Pulses(us)='
+ mystring += ','.join(str(int(int(x) * 1000000 / self.samplerate))
+ for x in self.pulse_lengths)
+ mystring += '\n'
+ self.put(self.samplenum - 10, self.samplenum, self.out_binary,
+ [0, bytes([ord(c) for c in mystring])])
+
+ def decode_nrz(self, start, samples, state):
+ self.pulse_lengths.append(samples)
+ # Use different high and low widths to compensate skewed waveforms.
+ if state == '1':
+ dsamples = self.sample_high
+ else:
+ dsamples = self.sample_low
+ self.ss = start
+ self.es = start + samples
+ while samples > dsamples * 0.5:
+ if samples >= dsamples * 1.5: # More than one bit.
+ self.es = self.ss + dsamples
+ self.putx([5, [state]])
+ self.decoded.append([self.ss, self.es, state])
+ self.edge_count += 1
+ elif samples >= dsamples * 0.5 and samples < dsamples * 1.5: # Last bit.
+ self.putx([5, [state]])
+ self.decoded.append([self.ss, self.es, state])
+ self.edge_count += 1
+ else:
+ self.edge_count += 1
+ samples -= dsamples
+ self.ss += dsamples
+ self.es += dsamples
+
+ # Ensure 2nd row doesn't go past end of 1st row.
+ if self.es > self.samplenum:
+ self.es = self.samplenum
+
+ if self.state == 'DECODE_TIMEOUT': # Five bits - reset.
+ self.ss = self.decoded[0][0]
+ self.es = self.decoded[len(self.decoded) - 1][1]
+ self.dump_pulse_lengths()
+ self.putp(self.decoded)
+ self.decode_timeout()
+ break
+
+ def lock_onto_preamble(self, samples, state): # Filters and recovers clock.
+ self.edge_count += 1
+ l2s = 5 # Max ratio of long to short pulses.
+
+ # Filter incoming pulses to remove random noise.
+ if self.state == 'DECODE_TIMEOUT':
+ self.preamble = []
+ self.edge_count == 0
+ self.word_first = self.samplenum
+ self.sample_first = self.samplenum - self.samplenumber_last
+ self.state = 'WAITING_FOR_PREAMBLE'
+ self.man_errors = 0
+
+ pre_detect = int(self.preamble_len) # Number of valid pulses to detect.
+ pre_samples = self.samplenum - self.samplenumber_last
+ if len(self.preamble) > 0:
+ if (pre_samples * l2s < self.preamble[-1][1] or
+ self.preamble[-1][1] * l2s < pre_samples): # Garbage in.
+ self.put(self.samplenum, self.samplenum,
+ self.out_ann, [0, ['R']]) # Display resets.
+ self.preamble = [] # Clear buffer.
+ self.preamble.append([self.samplenumber_last,
+ pre_samples, state])
+ self.edge_count == 0
+ self.samplenumber_last = self.samplenum
+ self.word_first = self.samplenum
+ else:
+ self.preamble.append([self.samplenumber_last,
+ pre_samples, state])
+ else:
+ self.preamble.append([self.samplenumber_last,
+ pre_samples, state])
+
+ pre = self.preamble
+ if len(self.preamble) == pre_detect: # Have a valid series of pulses.
+ if self.preamble[0][2] == '1':
+ self.sample_high = self.preamble[0][1] # Allows skewed pulses.
+ self.sample_low = self.preamble[1][1]
+ else:
+ self.sample_high = self.preamble[1][1]
+ self.sample_low = self.preamble[0][1]
+
+ self.edge_count = 0
+
+ for i in range(len(self.preamble)):
+ if i > 1:
+ if (pre[i][1] > pre[i - 2][1] * 1.25 or
+ pre[i][1] * 1.25 < pre[i - 2][1]): # Adjust ref width.
+ if pre[i][2] == '1':
+ self.sample_high = pre[i][1]
+ else:
+ self.sample_low = pre[i][1]
+
+ # Display start of preamble.
+ if self.decodeas == 'NRZ':
+ self.decode_nrz(pre[i][0], pre[i][1], pre[i][2])
+ if self.decodeas == 'Manchester':
+ self.decode_manchester(pre[i][0], pre[i][1], pre[i][2])
+ if self.decodeas == 'Diff Manchester':
+ self.es = pre[i][0] + pre[i][1]
+ self.decode_diff_manchester(pre[i][0], pre[i][1], pre[i][2])
+
+ # Used to timeout signal.
+ self.sample_first = int((self.sample_high + self.sample_low)/2)
+ self.insync = 1
+ self.state = 'DECODING'
+ self.lstate = state
+ self.lstate_1010 = state
+
+ def decode_diff_manchester(self, start, samples, state):
+ self.pulse_lengths.append(samples)
+
+ # Use different high and low widths to compensate skewed waveforms.
+ if state == '1':
+ dsamples = self.sample_high
+ else:
+ dsamples = self.sample_low
+
+ self.es = start + samples
+ p_length = round(samples / dsamples) # Find relative pulse length.
+
+ if self.edge_count == 0:
+ self.diff_man_trans = '1' # Very first pulse must be a transition.
+ self.diff_man_len = 1 # Must also be a half pulse.
+ self.ss = start
+ elif self.edge_count % 2 == 1: # Time to make a decision.
+ if self.diffmanvar == '0': # Transition at self.ss is a zero.
+ self.diff_man_trans = '0' if self.diff_man_trans == '1' else '1'
+ if self.diff_man_len == 1 and p_length == 1:
+ self.putx([4, [self.diff_man_trans]])
+ self.decoded.append([self.ss, self.es, self.diff_man_trans])
+ self.diff_man_trans = '1'
+ elif self.diff_man_len == 1 and p_length == 2:
+ self.es -= int(samples / 2)
+ self.putx([4, [self.diff_man_trans]])
+ self.decoded.append([self.ss, self.es, self.diff_man_trans])
+ self.diff_man_trans = '0'
+ self.edge_count += 1 # Add a virt edge to keep in sync with clk.
+ elif self.diff_man_len == 2 and p_length == 1:
+ self.putx([4, [self.diff_man_trans]])
+ self.decoded.append([self.ss, self.es, self.diff_man_trans])
+ self.diff_man_trans = '1'
+ elif self.diff_man_len == 2 and p_length == 2: # Double illegal E E.
+ self.es -= samples
+ self.putx([4, ['E']])
+ self.decoded.append([self.ss, self.es, 'E'])
+ self.ss = self.es
+ self.es += samples
+ self.putx([4, ['E']])
+ self.decoded.append([self.ss, self.es, 'E'])
+ self.diff_man_trans = '1'
+ elif self.diff_man_len == 1 and p_length > 4:
+ if self.state == 'DECODE_TIMEOUT':
+ self.es = self.ss + 2 * self.sample_first
+ self.putx([4, [self.diff_man_trans]]) # Write error.
+ self.decoded.append([self.ss, self.es, self.diff_man_trans])
+ self.ss = self.decoded[0][0]
+ self.es = self.decoded[len(self.decoded) - 1][1]
+ self.dump_pulse_lengths()
+ if self.man_errors < self.max_errors:
+ self.putp(self.decoded)
+ else:
+ error_message = 'Probably not Diff Manchester encoded'
+ self.ss = self.word_first
+ self.putx([1, [error_message]])
+ self.decode_timeout()
+ self.diff_man_trans = '1'
+ self.ss = self.es
+ self.diff_man_len = p_length # Save the previous length.
+ self.edge_count += 1
+
+ def decode_manchester_sim(self, start, samples, state,
+ dsamples, half_time, lstate, ss, pream):
+ ook_bit = []
+ errors = 0
+ if self.edge_count == 0:
+ half_time += 1
+ if samples > 0.75 * dsamples and samples <= 1.5 * dsamples: # Long p.
+ half_time += 2
+ if half_time % 2 == 0: # Transition.
+ es = start
+ else:
+ es = start + int(samples / 2)
+ if ss == start:
+ lstate = 'E'
+ es = start + samples
+ if not (self.edge_count == 0 and pream == '1010'): # Skip first p.
+ ook_bit = [ss, es, lstate]
+ lstate = state
+ ss = es
+ elif samples > 0.25 * dsamples and samples <= 0.75 * dsamples: # Short p.
+ half_time += 1
+ if (half_time % 2 == 0): # Transition.
+ es = start + samples
+ ook_bit = [ss, es, lstate]
+ lstate = state
+ ss = es
+ else: # 1st half.
+ ss = start
+ lstate = state
+ else: # Too long or too short - error.
+ errors = 1
+ if self.state != 'DECODE_TIMEOUT': # Error condition.
+ lstate = 'E'
+ es = ss + samples
+ else: # Assume final half bit buried in timeout pulse.
+ es = ss + self.sample_first
+ ook_bit = [ss, es, lstate]
+ ss = es
+
+ return (half_time, lstate, ss, ook_bit, errors)
+
+ def decode_manchester(self, start, samples, state):
+ self.pulse_lengths.append(samples)
+
+ # Use different high and low widths to compensate skewed waveforms.
+ if state == '1':
+ dsamples = self.sample_high
+ else:
+ dsamples = self.sample_low
+
+ if self.preamble_val != '1010': # 1111 preamble is half clock T.
+ (self.half_time, self.lstate, self.ss_1111, ook_bit, errors) = (
+ self.decode_manchester_sim(start, samples, state, dsamples * 2,
+ self.half_time, self.lstate,
+ self.ss_1111, '1111'))
+ self.man_errors += errors
+ if ook_bit != []:
+ self.decoded.append([ook_bit[0], ook_bit[1], ook_bit[2]])
+
+ if self.preamble_val != '1111': # 1010 preamble is clock T.
+ (self.half_time_1010, self.lstate_1010, self.ss_1010,
+ ook_bit, errors) = (
+ self.decode_manchester_sim(start, samples, state, dsamples,
+ self.half_time_1010, self.lstate_1010,
+ self.ss_1010, '1010'))
+ self.man_errors_1010 += errors
+ if ook_bit != []:
+ self.decoded_1010.append([ook_bit[0], ook_bit[1], ook_bit[2]])
+
+ self.edge_count += 1
+
+ # Stream display and save ook_bit.
+ if ook_bit != []:
+ self.ss = ook_bit[0]
+ self.es = ook_bit[1]
+ if self.preamble_val == '1111':
+ self.putx([2, [ook_bit[2]]])
+ if self.preamble_val == '1010':
+ self.putx([3, [ook_bit[2]]])
+
+ if self.state == 'DECODE_TIMEOUT': # End of packet.
+ self.dump_pulse_lengths()
+
+ decoded = []
+ # If 1010 preamble has less errors use it.
+ if (self.preamble_val == '1010' or
+ (self.man_errors_1010 < self.max_errors and
+ self.man_errors_1010 < self.man_errors and
+ len(self.decoded_1010) > 0)):
+ decoded = self.decoded_1010
+ man_errors = self.man_errors_1010
+ d_row = 3
+ else:
+ decoded = self.decoded
+ man_errors = self.man_errors
+ d_row = 2
+
+ if self.preamble_val == 'auto': # Display OOK packet.
+ for i in range(len(decoded)):
+ self.ss = decoded[i][0]
+ self.es = decoded[i][1]
+ self.putx([d_row, [decoded[i][2]]])
+
+ if (man_errors < self.max_errors and len(decoded) > 0):
+ self.ss = decoded[0][0]
+ self.es = decoded[len(decoded) - 1][1]
+ self.putp(decoded)
+ else:
+ error_message = 'Not Manchester encoded or wrong preamble'
+ self.ss = self.word_first
+ self.putx([1, [error_message]])
+
+ self.put(self.es, self.es, self.out_ann, [0, ['T']]) # Mark timeout.
+ self.decode_timeout()
+
+ def decode_timeout(self):
+ self.word_count = 0
+ self.samplenumber_last = None
+ self.edge_count = 0
+ self.man_errors = 0 # Clear the bit error counters.
+ self.man_errors_1010 = 0
+ self.state = 'IDLE'
+ self.wait({0: 'e'}) # Get rid of long pulse.
+ self.samplenumber_last = self.samplenum
+ self.word_first = self.samplenum
+ self.insync = 0 # Preamble in sync flag
+ self.preamble = [] # Preamble buffer
+ self.half_time = -1 # Half time for man 1111
+ self.half_time_1010 = 0 # Half time for man 1010
+ self.decoded = [] # Decoded bits
+ self.decoded_1010 = [] # Decoded bits for man 1010
+ self.pulse_lengths = []
+
+ def decode(self):
+ while True:
+ if self.edge_count == 0: # Waiting for a signal.
+ pin = self.wait({0: 'e'})
+ self.state = 'DECODING'
+ else:
+ pin = self.wait([{0: 'e'}, {'skip': 5 * self.sample_first}])
+ if self.matched[1] and not self.matched[0]: # No edges for 5 p's.
+ self.state = 'DECODE_TIMEOUT'
+
+ if not self.samplenumber_last: # Set counters to start of signal.
+ self.samplenumber_last = self.samplenum
+ self.word_first = self.samplenum
+ continue
+ samples = self.samplenum - self.samplenumber_last
+ if not self.sample_first: # Get number of samples for first pulse.
+ self.sample_first = samples
+
+ pinstate = pin[0]
+ if self.state == 'DECODE_TIMEOUT': # No edge so flip the state.
+ pinstate = int(not pinstate)
+ if self.invert == 'yes': # Invert signal.
+ pinstate = int(not pinstate)
+ if pinstate:
+ state = '0'
+ else:
+ state = '1'
+
+ # No preamble filtering or checking and no skew correction.
+ if self.preamble_len == '0':
+ self.sample_high = self.sample_first
+ self.sample_low = self.sample_first
+ self.insync = 0
+
+ if self.insync == 0:
+ self.lock_onto_preamble(samples, state)
+ else:
+ if self.decodeas == 'NRZ':
+ self.decode_nrz(self.samplenumber_last, samples, state)
+ if self.decodeas == 'Manchester':
+ self.decode_manchester(self.samplenumber_last,
+ samples, state)
+ if self.decodeas == 'Diff Manchester':
+ self.decode_diff_manchester(self.samplenumber_last,
+ samples, state)
+
+ self.samplenumber_last = self.samplenum
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