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