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27ea5bac 1##
2## This file is part of the libsigrokdecode project.
3##
4## Copyright (C) 2016 Fabian J. Stumpf <sigrok@fabianstumpf.de>
5##
6## This program is free software; you can redistribute it and/or modify
7## it under the terms of the GNU General Public License as published by
8## the Free Software Foundation; either version 2 of the License, or
9## (at your option) any later version.
10##
11## This program is distributed in the hope that it will be useful,
12## but WITHOUT ANY WARRANTY; without even the implied warranty of
13## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14## GNU General Public License for more details.
15##
16## You should have received a copy of the GNU General Public License
4539e9ca 17## along with this program; if not, see <http://www.gnu.org/licenses/>.
27ea5bac 18##
19
20import sigrokdecode as srd
21
22class Decoder(srd.Decoder):
2ba06442 23 api_version = 3
27ea5bac 24 id = 'dmx512'
25 name = 'DMX512'
26 longname = 'Digital MultipleX 512'
27 desc = 'Professional lighting control protocol.'
28 license = 'gplv2+'
29 inputs = ['logic']
30 outputs = ['dmx512']
31 channels = (
32 {'id': 'dmx', 'name': 'DMX data', 'desc': 'Any DMX data line'},
33 )
34 annotations = (
35 ('bit', 'Bit'),
36 ('break', 'Break'),
37 ('mab', 'Mark after break'),
38 ('startbit', 'Start bit'),
39 ('stopbits', 'Stop bit'),
40 ('startcode', 'Start code'),
41 ('channel', 'Channel'),
42 ('interframe', 'Interframe'),
43 ('interpacket', 'Interpacket'),
44 ('data', 'Data'),
45 ('error', 'Error'),
46 )
47 annotation_rows = (
48 ('name', 'Logical', (1, 2, 5, 6, 7, 8)),
49 ('data', 'Data', (9,)),
50 ('bits', 'Bits', (0, 3, 4)),
51 ('errors', 'Errors', (10,)),
52 )
53
54 def __init__(self):
2ba06442
UH
55 self.reset()
56
57 def reset(self):
27ea5bac 58 self.samplerate = None
59 self.sample_usec = None
27ea5bac 60 self.run_start = -1
61 self.run_bit = 0
62 self.state = 'FIND BREAK'
63
64 def start(self):
65 self.out_ann = self.register(srd.OUTPUT_ANN)
66
67 def metadata(self, key, value):
68 if key == srd.SRD_CONF_SAMPLERATE:
69 self.samplerate = value
70 self.sample_usec = 1 / value * 1000000
71 self.skip_per_bit = int(4 / self.sample_usec)
72
73 def putr(self, data):
74 self.put(self.run_start, self.samplenum, self.out_ann, data)
75
2ba06442 76 def decode(self):
27ea5bac 77 if not self.samplerate:
78 raise SamplerateError('Cannot decode without samplerate.')
2ba06442 79 while True:
27ea5bac 80 # Seek for an interval with no state change with a length between
81 # 88 and 1000000 us (BREAK).
82 if self.state == 'FIND BREAK':
2ba06442 83 (dmx,) = self.wait({0: 'h' if self.run_bit == 0 else 'l'})
27ea5bac 84 runlen = (self.samplenum - self.run_start) * self.sample_usec
85 if runlen > 88 and runlen < 1000000:
86 self.putr([1, ['Break']])
87 self.bit_break = self.run_bit
88 self.state = 'MARK MAB'
89 self.channel = 0
90 elif runlen >= 1000000:
91 # Error condition.
92 self.putr([10, ['Invalid break length']])
2ba06442 93 self.run_bit = dmx
27ea5bac 94 self.run_start = self.samplenum
95 # Directly following the BREAK is the MARK AFTER BREAK.
96 elif self.state == 'MARK MAB':
2ba06442 97 (dmx,) = self.wait({0: 'h' if self.run_bit == 0 else 'l'})
27ea5bac 98 self.putr([2, ['MAB']])
99 self.state = 'READ BYTE'
100 self.channel = 0
101 self.bit = 0
2ba06442 102 self.aggreg = dmx
27ea5bac 103 self.run_start = self.samplenum
104 # Mark and read a single transmitted byte
105 # (start bit, 8 data bits, 2 stop bits).
106 elif self.state == 'READ BYTE':
2ba06442 107 (dmx,) = self.wait()
27ea5bac 108 self.next_sample = self.run_start + (self.bit + 1) * self.skip_per_bit
2ba06442 109 self.aggreg += dmx
27ea5bac 110 if self.samplenum != self.next_sample:
111 continue
112 bit_value = 0 if round(self.aggreg/self.skip_per_bit) == self.bit_break else 1
113
114 if self.bit == 0:
115 self.byte = 0
116 self.putr([3, ['Start bit']])
117 if bit_value != 0:
118 # (Possibly) invalid start bit, mark but don't fail.
119 self.put(self.samplenum, self.samplenum,
120 self.out_ann, [10, ['Invalid start bit']])
121 elif self.bit >= 9:
122 self.put(self.samplenum - self.skip_per_bit,
123 self.samplenum, self.out_ann, [4, ['Stop bit']])
124 if bit_value != 1:
125 # Invalid stop bit, mark.
126 self.put(self.samplenum, self.samplenum,
127 self.out_ann, [10, ['Invalid stop bit']])
128 if self.bit == 10:
129 # On invalid 2nd stop bit, search for new break.
2ba06442 130 self.run_bit = dmx
27ea5bac 131 self.state = 'FIND BREAK'
132 else:
133 # Label and process one bit.
134 self.put(self.samplenum - self.skip_per_bit,
135 self.samplenum, self.out_ann, [0, [str(bit_value)]])
136 self.byte |= bit_value << (self.bit - 1)
137
138 # Label a complete byte.
139 if self.bit == 10:
140 if self.channel == 0:
141 d = [5, ['Start code']]
142 else:
143 d = [6, ['Channel ' + str(self.channel)]]
144 self.put(self.run_start, self.next_sample, self.out_ann, d)
145 self.put(self.run_start + self.skip_per_bit,
146 self.next_sample - 2 * self.skip_per_bit,
147 self.out_ann, [9, [str(self.byte) + ' / ' + \
148 str(hex(self.byte))]])
149 # Continue by scanning the IFT.
150 self.channel += 1
151 self.run_start = self.samplenum
2ba06442 152 self.run_bit = dmx
27ea5bac 153 self.state = 'MARK IFT'
154
2ba06442 155 self.aggreg = dmx
27ea5bac 156 self.bit += 1
157 # Mark the INTERFRAME-TIME between bytes / INTERPACKET-TIME between packets.
158 elif self.state == 'MARK IFT':
2ba06442 159 (dmx,) = self.wait({0: 'h' if self.run_bit == 0 else 'l'})
27ea5bac 160 if self.channel > 512:
161 self.putr([8, ['Interpacket']])
162 self.state = 'FIND BREAK'
2ba06442 163 self.run_bit = dmx
27ea5bac 164 self.run_start = self.samplenum
165 else:
166 self.putr([7, ['Interframe']])
167 self.state = 'READ BYTE'
168 self.bit = 0
169 self.run_start = self.samplenum