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 = 'Professional lighting control protocol.'
32 {'id': 'dmx', 'name': 'DMX data', 'desc': 'Any DMX data line'},
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'),
48 ('name', 'Logical', (1, 2, 5, 6, 7, 8)),
49 ('data', 'Data', (9,)),
50 ('bits', 'Bits', (0, 3, 4)),
51 ('errors', 'Errors', (10,)),
58 self.samplerate = None
59 self.sample_usec = None
62 self.state = 'FIND BREAK'
65 self.out_ann = self.register(srd.OUTPUT_ANN)
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)
74 self.put(self.run_start, self.samplenum, self.out_ann, data)
77 if not self.samplerate:
78 raise SamplerateError('Cannot decode without samplerate.')
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':
83 (dmx,) = self.wait({0: 'h' if self.run_bit == 0 else 'l'})
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'
90 elif runlen >= 1000000:
92 self.putr([10, ['Invalid break length']])
94 self.run_start = self.samplenum
95 # Directly following the BREAK is the MARK AFTER BREAK.
96 elif self.state == 'MARK MAB':
97 (dmx,) = self.wait({0: 'h' if self.run_bit == 0 else 'l'})
98 self.putr([2, ['MAB']])
99 self.state = 'READ BYTE'
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':
108 self.next_sample = self.run_start + (self.bit + 1) * self.skip_per_bit
110 if self.samplenum != self.next_sample:
112 bit_value = 0 if round(self.aggreg/self.skip_per_bit) == self.bit_break else 1
116 self.putr([3, ['Start bit']])
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']])
122 self.put(self.samplenum - self.skip_per_bit,
123 self.samplenum, self.out_ann, [4, ['Stop bit']])
125 # Invalid stop bit, mark.
126 self.put(self.samplenum, self.samplenum,
127 self.out_ann, [10, ['Invalid stop bit']])
129 # On invalid 2nd stop bit, search for new break.
131 self.state = 'FIND BREAK'
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)
138 # Label a complete byte.
140 if self.channel == 0:
141 d = [5, ['Start code']]
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.
151 self.run_start = self.samplenum
153 self.state = 'MARK IFT'
157 # Mark the INTERFRAME-TIME between bytes / INTERPACKET-TIME between packets.
158 elif self.state == 'MARK IFT':
159 (dmx,) = self.wait({0: 'h' if self.run_bit == 0 else 'l'})
160 if self.channel > 512:
161 self.putr([8, ['Interpacket']])
162 self.state = 'FIND BREAK'
164 self.run_start = self.samplenum
166 self.putr([7, ['Interframe']])
167 self.state = 'READ BYTE'
169 self.run_start = self.samplenum