2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2016 Fabian J. Stumpf <sigrok@fabianstumpf.de>
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.
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.
16 ## You should have received a copy of the GNU General Public License
17 ## along with this program; if not, see <http://www.gnu.org/licenses/>.
20 import sigrokdecode as srd
22 class Decoder(srd.Decoder):
26 longname = 'Digital MultipleX 512'
27 desc = 'Digital MultipleX 512 (DMX512) lighting protocol.'
31 tags = ['Embedded/industrial', 'Lighting']
33 {'id': 'dmx', 'name': 'DMX data', 'desc': 'Any DMX data line'},
38 ('mab', 'Mark after break'),
39 ('startbit', 'Start bit'),
40 ('stopbits', 'Stop bit'),
41 ('startcode', 'Start code'),
42 ('channel', 'Channel'),
43 ('interframe', 'Interframe'),
44 ('interpacket', 'Interpacket'),
49 ('bits', 'Bits', (0, 3, 4)),
50 ('data', 'Data', (9,)),
51 ('name', 'Logical', (1, 2, 5, 6, 7, 8)),
52 ('errors', 'Errors', (10,)),
59 self.samplerate = None
60 self.sample_usec = None
63 self.state = 'FIND BREAK'
66 self.out_ann = self.register(srd.OUTPUT_ANN)
68 def metadata(self, key, value):
69 if key == srd.SRD_CONF_SAMPLERATE:
70 self.samplerate = value
71 self.sample_usec = 1 / value * 1000000
72 self.skip_per_bit = int(4 / self.sample_usec)
75 self.put(self.run_start, self.samplenum, self.out_ann, data)
78 if not self.samplerate:
79 raise SamplerateError('Cannot decode without samplerate.')
81 # Seek for an interval with no state change with a length between
82 # 88 and 1000000 us (BREAK).
83 if self.state == 'FIND BREAK':
84 (dmx,) = self.wait({0: 'h' if self.run_bit == 0 else 'l'})
85 runlen = (self.samplenum - self.run_start) * self.sample_usec
86 if runlen > 88 and runlen < 1000000:
87 self.putr([1, ['Break']])
88 self.bit_break = self.run_bit
89 self.state = 'MARK MAB'
91 elif runlen >= 1000000:
93 self.putr([10, ['Invalid break length']])
95 self.run_start = self.samplenum
96 # Directly following the BREAK is the MARK AFTER BREAK.
97 elif self.state == 'MARK MAB':
98 (dmx,) = self.wait({0: 'h' if self.run_bit == 0 else 'l'})
99 self.putr([2, ['MAB']])
100 self.state = 'READ BYTE'
104 self.run_start = self.samplenum
105 # Mark and read a single transmitted byte
106 # (start bit, 8 data bits, 2 stop bits).
107 elif self.state == 'READ BYTE':
109 self.next_sample = self.run_start + (self.bit + 1) * self.skip_per_bit
111 if self.samplenum != self.next_sample:
113 bit_value = 0 if round(self.aggreg/self.skip_per_bit) == self.bit_break else 1
117 self.putr([3, ['Start bit']])
119 # (Possibly) invalid start bit, mark but don't fail.
120 self.put(self.samplenum, self.samplenum,
121 self.out_ann, [10, ['Invalid start bit']])
123 self.put(self.samplenum - self.skip_per_bit,
124 self.samplenum, self.out_ann, [4, ['Stop bit']])
126 # Invalid stop bit, mark.
127 self.put(self.samplenum, self.samplenum,
128 self.out_ann, [10, ['Invalid stop bit']])
130 # On invalid 2nd stop bit, search for new break.
132 self.state = 'FIND BREAK'
134 # Label and process one bit.
135 self.put(self.samplenum - self.skip_per_bit,
136 self.samplenum, self.out_ann, [0, [str(bit_value)]])
137 self.byte |= bit_value << (self.bit - 1)
139 # Label a complete byte.
141 if self.channel == 0:
142 d = [5, ['Start code']]
144 d = [6, ['Channel ' + str(self.channel)]]
145 self.put(self.run_start, self.next_sample, self.out_ann, d)
146 self.put(self.run_start + self.skip_per_bit,
147 self.next_sample - 2 * self.skip_per_bit,
148 self.out_ann, [9, [str(self.byte) + ' / ' + \
149 str(hex(self.byte))]])
150 # Continue by scanning the IFT.
152 self.run_start = self.samplenum
154 self.state = 'MARK IFT'
158 # Mark the INTERFRAME-TIME between bytes / INTERPACKET-TIME between packets.
159 elif self.state == 'MARK IFT':
160 (dmx,) = self.wait({0: 'h' if self.run_bit == 0 else 'l'})
161 if self.channel > 512:
162 self.putr([8, ['Interpacket']])
163 self.state = 'FIND BREAK'
165 self.run_start = self.samplenum
167 self.putr([7, ['Interframe']])
168 self.state = 'READ BYTE'
170 self.run_start = self.samplenum