2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2014 Guenther Wenninger <robin@bitschubbser.org>
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, write to the Free Software
18 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 import sigrokdecode as srd
23 class SamplerateError(Exception):
26 class Decoder(srd.Decoder):
30 longname = 'Sony/Philips Digital Interface Format'
31 desc = 'Serial bus for connecting digital audio devices.'
36 {'id': 'data', 'name': 'Data', 'desc': 'Data line'},
39 ('bitrate', 'Bitrate / baudrate'),
40 ('preamble', 'Preamble'),
42 ('aux', 'Auxillary-audio-databits'),
43 ('samples', 'Audio Samples'),
44 ('validity', 'Data Valid'),
45 ('subcode', 'Subcode data'),
46 ('chan_stat', 'Channnel Status'),
47 ('parity', 'Parity Bit'),
50 ('info', 'Info', (0, 1, 3, 5, 6, 7, 8)),
51 ('bits', 'Bits', (2,)),
52 ('samples', 'Samples', (4,)),
55 def putx(self, ss, es, data):
56 self.put(ss, es, self.out_ann, data)
59 self.put(self.ss_edge, self.samplenum, self.out_ann, data)
61 def __init__(self, **kwargs):
62 self.state = 'GET FIRST PULSE WIDTH'
65 self.first_edge = True
72 self.preamble_state = 0
74 self.seen_preamble = False
75 self.last_preamble = 0
81 self.out_ann = self.register(srd.OUTPUT_ANN)
83 def metadata(self, key, value):
84 if key == srd.SRD_CONF_SAMPLERATE:
85 self.samplerate = value
87 def get_pulse_type(self):
88 if self.range1 == 0 or self.range2 == 0:
90 if self.pulse_width >= self.range2:
92 elif self.pulse_width >= self.range1:
97 def find_first_pulse_width(self):
98 if self.pulse_width != 0:
99 self.clocks.append(self.pulse_width)
100 self.state = 'GET SECOND PULSE WIDTH'
102 def find_second_pulse_width(self):
103 if self.pulse_width > (self.clocks[0] * 1.3) or \
104 self.pulse_width < (self.clocks[0] * 0.7):
105 self.clocks.append(self.pulse_width)
106 self.state = 'GET THIRD PULSE WIDTH'
108 def find_third_pulse_width(self):
109 if not ((self.pulse_width > (self.clocks[0] * 1.3) or \
110 self.pulse_width < (self.clocks[0] * 0.7)) \
111 and (self.pulse_width > (self.clocks[1] * 1.3) or \
112 self.pulse_width < (self.clocks[1] * 0.7))):
115 self.clocks.append(self.pulse_width)
117 self.range1 = (self.clocks[0] + self.clocks[1]) / 2
118 self.range2 = (self.clocks[1] + self.clocks[2]) / 2
119 spdif_bitrate = int(self.samplerate / (self.clocks[2] / 1.5))
122 self.puty([0, ['Signal Bitrate: %d Mbit/s (=> %d kHz)' % \
123 (spdif_bitrate, (spdif_bitrate/ (2 * 32)))]])
125 clock_period_nsec = 1000000000 / spdif_bitrate
127 self.last_preamble = self.samplenum
129 # We are done recovering the clock, now let's decode the data stream.
130 self.state = 'DECODE STREAM'
132 def decode_stream(self):
133 pulse = self.get_pulse_type()
135 if not self.seen_preamble:
136 # This is probably the start of a preamble, decode it.
138 self.preamble.append(self.get_pulse_type())
139 self.state = 'DECODE PREAMBLE'
140 self.ss_edge = self.samplenum - self.pulse_width - 1
143 # We've seen a preamble.
144 if pulse == 1 and self.first_one:
145 self.first_one = False
146 self.subframe.append([pulse, self.samplenum - \
147 self.pulse_width - 1, self.samplenum])
148 elif pulse == 1 and not self.first_one:
149 self.subframe[-1][2] = self.samplenum
150 self.putx(self.subframe[-1][1], self.samplenum, [2, ['1']])
152 self.first_one = True
154 self.subframe.append([pulse, self.samplenum - \
155 self.pulse_width - 1, self.samplenum])
156 self.putx(self.samplenum - self.pulse_width - 1,
157 self.samplenum, [2, ['0']])
160 if self.bitcount == 28:
161 aux_audio_data = self.subframe[0:4]
162 sam, sam_rot = '', ''
163 for a in aux_audio_data:
164 sam = sam + str(a[0])
165 sam_rot = str(a[0]) + sam_rot
166 sample = self.subframe[4:24]
168 sam = sam + str(s[0])
169 sam_rot = str(s[0]) + sam_rot
170 validity = self.subframe[24:25]
171 subcode_data = self.subframe[25:26]
172 channel_status = self.subframe[26:27]
173 parity = self.subframe[27:28]
175 self.putx(aux_audio_data[0][1], aux_audio_data[3][2], \
176 [3, ['Aux 0x%x' % int(sam, 2), '0x%x' % int(sam, 2)]])
177 self.putx(sample[0][1], sample[19][2], \
178 [3, ['Sample 0x%x' % int(sam, 2), '0x%x' % int(sam, 2)]])
179 self.putx(aux_audio_data[0][1], sample[19][2], \
180 [4, ['Audio 0x%x' % int(sam_rot, 2), '0x%x' % int(sam_rot, 2)]])
181 if validity[0][0] == 0:
182 self.putx(validity[0][1], validity[0][2], [5, ['V']])
184 self.putx(validity[0][1], validity[0][2], [5, ['E']])
185 self.putx(subcode_data[0][1], subcode_data[0][2],
186 [6, ['S: %d' % subcode_data[0][0]]])
187 self.putx(channel_status[0][1], channel_status[0][2],
188 [7, ['C: %d' % channel_status[0][0]]])
189 self.putx(parity[0][1], parity[0][2], [8, ['P: %d' % parity[0][0]]])
192 self.seen_preamble = False
195 def decode_preamble(self):
196 if self.preamble_state == 0:
197 self.preamble.append(self.get_pulse_type())
198 self.preamble_state = 1
199 elif self.preamble_state == 1:
200 self.preamble.append(self.get_pulse_type())
201 self.preamble_state = 2
202 elif self.preamble_state == 2:
203 self.preamble.append(self.get_pulse_type())
204 self.preamble_state = 0
205 self.state = 'DECODE STREAM'
206 if self.preamble == [2, 0, 1, 0]:
207 self.puty([1, ['Preamble W', 'W']])
208 elif self.preamble == [2, 2, 1, 1]:
209 self.puty([1, ['Preamble M', 'M']])
210 elif self.preamble == [2, 1, 1, 2]:
211 self.puty([1, ['Preamble B', 'B']])
213 self.puty([1, ['Unknown Preamble', 'Unkown Prea.', 'U']])
215 self.seen_preamble = True
217 self.first_one = True
219 self.last_preamble = self.samplenum
221 def decode(self, ss, es, data):
222 if not self.samplerate:
223 raise SamplerateError('Cannot decode without samplerate.')
225 for (self.samplenum, pins) in data:
228 # Initialize self.olddata with the first sample value.
229 if self.olddata is None:
233 # First we need to recover the clock.
234 if self.olddata == data:
235 self.pulse_width += 1
238 # Found rising or falling edge.
240 # Throw away first detected edge as it might be mangled data.
241 self.first_edge = False
244 if self.state == 'GET FIRST PULSE WIDTH':
245 self.find_first_pulse_width()
246 elif self.state == 'GET SECOND PULSE WIDTH':
247 self.find_second_pulse_width()
248 elif self.state == 'GET THIRD PULSE WIDTH':
249 self.find_third_pulse_width()
250 elif self.state == 'DECODE STREAM':
252 elif self.state == 'DECODE PREAMBLE':
253 self.decode_preamble()