mirror of
https://github.com/DreamSourceLab/DSView.git
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247 lines
8.8 KiB
Python
247 lines
8.8 KiB
Python
##
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## This file is part of the libsigrokdecode project.
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##
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## Copyright (C) 2014 Guenther Wenninger <robin@bitschubbser.org>
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##
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## This program is free software; you can redistribute it and/or modify
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## it under the terms of the GNU General Public License as published by
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## the Free Software Foundation; either version 2 of the License, or
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## (at your option) any later version.
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##
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## This program is distributed in the hope that it will be useful,
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## but WITHOUT ANY WARRANTY; without even the implied warranty of
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## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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## GNU General Public License for more details.
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##
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## You should have received a copy of the GNU General Public License
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## along with this program; if not, see <http://www.gnu.org/licenses/>.
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##
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import sigrokdecode as srd
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class SamplerateError(Exception):
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pass
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class Decoder(srd.Decoder):
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api_version = 3
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id = 'spdif'
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name = 'S/PDIF'
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longname = 'Sony/Philips Digital Interface Format'
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desc = 'Serial bus for connecting digital audio devices.'
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license = 'gplv2+'
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inputs = ['logic']
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outputs = []
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tags = ['Audio', 'PC']
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channels = (
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{'id': 'data', 'name': 'Data', 'desc': 'Data line', 'idn':'dec_spdif_chan_data'},
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)
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annotations = (
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('bitrate', 'Bitrate / baudrate'),
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('preamble', 'Preamble'),
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('bits', 'Bits'),
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('aux', 'Auxillary-audio-databits'),
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('samples', 'Audio Samples'),
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('validity', 'Data Valid'),
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('subcode', 'Subcode data'),
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('chan_stat', 'Channnel Status'),
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('parity', 'Parity Bit'),
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)
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annotation_rows = (
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('info', 'Info', (0, 1, 3, 5, 6, 7, 8)),
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('bits', 'Bits', (2,)),
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('samples', 'Samples', (4,)),
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)
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def putx(self, ss, es, data):
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self.put(ss, es, self.out_ann, data)
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def puty(self, data):
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self.put(self.ss_edge, self.samplenum, self.out_ann, data)
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def __init__(self):
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self.reset()
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def reset(self):
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self.state = 'GET FIRST PULSE WIDTH'
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self.ss_edge = None
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self.first_edge = True
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self.samplenum_prev_edge = 0
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self.pulse_width = 0
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self.clocks = []
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self.range1 = 0
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self.range2 = 0
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self.preamble_state = 0
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self.preamble = []
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self.seen_preamble = False
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self.last_preamble = 0
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self.first_one = True
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self.subframe = []
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def start(self):
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self.out_ann = self.register(srd.OUTPUT_ANN)
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def metadata(self, key, value):
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if key == srd.SRD_CONF_SAMPLERATE:
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self.samplerate = value
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def get_pulse_type(self):
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if self.range1 == 0 or self.range2 == 0:
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return -1
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if self.pulse_width >= self.range2:
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return 2
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elif self.pulse_width >= self.range1:
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return 0
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else:
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return 1
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def find_first_pulse_width(self):
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if self.pulse_width != 0:
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self.clocks.append(self.pulse_width)
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self.state = 'GET SECOND PULSE WIDTH'
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def find_second_pulse_width(self):
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if self.pulse_width > (self.clocks[0] * 1.3) or \
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self.pulse_width < (self.clocks[0] * 0.7):
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self.clocks.append(self.pulse_width)
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self.state = 'GET THIRD PULSE WIDTH'
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def find_third_pulse_width(self):
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if not ((self.pulse_width > (self.clocks[0] * 1.3) or \
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self.pulse_width < (self.clocks[0] * 0.7)) \
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and (self.pulse_width > (self.clocks[1] * 1.3) or \
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self.pulse_width < (self.clocks[1] * 0.7))):
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return
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self.clocks.append(self.pulse_width)
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self.clocks.sort()
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self.range1 = (self.clocks[0] + self.clocks[1]) / 2
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self.range2 = (self.clocks[1] + self.clocks[2]) / 2
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spdif_bitrate = int(self.samplerate / (self.clocks[2] / 1.5))
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self.ss_edge = 0
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self.puty([0, ['Signal Bitrate: %d Mbit/s (=> %d kHz)' % \
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(spdif_bitrate, (spdif_bitrate/ (2 * 32)))]])
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clock_period_nsec = 1000000000 / spdif_bitrate
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self.last_preamble = self.samplenum
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# We are done recovering the clock, now let's decode the data stream.
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self.state = 'DECODE STREAM'
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def decode_stream(self):
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pulse = self.get_pulse_type()
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if not self.seen_preamble:
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# This is probably the start of a preamble, decode it.
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if pulse == 2:
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self.preamble.append(self.get_pulse_type())
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self.state = 'DECODE PREAMBLE'
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self.ss_edge = self.samplenum - self.pulse_width - 1
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return
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# We've seen a preamble.
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if pulse == 1 and self.first_one:
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self.first_one = False
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self.subframe.append([pulse, self.samplenum - \
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self.pulse_width - 1, self.samplenum])
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elif pulse == 1 and not self.first_one:
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self.subframe[-1][2] = self.samplenum
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self.putx(self.subframe[-1][1], self.samplenum, [2, ['1']])
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self.bitcount += 1
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self.first_one = True
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else:
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self.subframe.append([pulse, self.samplenum - \
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self.pulse_width - 1, self.samplenum])
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self.putx(self.samplenum - self.pulse_width - 1,
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self.samplenum, [2, ['0']])
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self.bitcount += 1
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if self.bitcount == 28:
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aux_audio_data = self.subframe[0:4]
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sam, sam_rot = '', ''
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for a in aux_audio_data:
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sam = sam + str(a[0])
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sam_rot = str(a[0]) + sam_rot
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sample = self.subframe[4:24]
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for s in sample:
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sam = sam + str(s[0])
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sam_rot = str(s[0]) + sam_rot
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validity = self.subframe[24:25]
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subcode_data = self.subframe[25:26]
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channel_status = self.subframe[26:27]
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parity = self.subframe[27:28]
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self.putx(aux_audio_data[0][1], aux_audio_data[3][2], \
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[3, ['Aux 0x%x' % int(sam, 2), '0x%x' % int(sam, 2)]])
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self.putx(sample[0][1], sample[19][2], \
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[3, ['Sample 0x%x' % int(sam, 2), '0x%x' % int(sam, 2)]])
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self.putx(aux_audio_data[0][1], sample[19][2], \
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[4, ['Audio 0x%x' % int(sam_rot, 2), '0x%x' % int(sam_rot, 2)]])
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if validity[0][0] == 0:
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self.putx(validity[0][1], validity[0][2], [5, ['V']])
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else:
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self.putx(validity[0][1], validity[0][2], [5, ['E']])
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self.putx(subcode_data[0][1], subcode_data[0][2],
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[6, ['S: %d' % subcode_data[0][0]]])
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self.putx(channel_status[0][1], channel_status[0][2],
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[7, ['C: %d' % channel_status[0][0]]])
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self.putx(parity[0][1], parity[0][2], [8, ['P: %d' % parity[0][0]]])
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self.subframe = []
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self.seen_preamble = False
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self.bitcount = 0
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def decode_preamble(self):
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if self.preamble_state == 0:
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self.preamble.append(self.get_pulse_type())
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self.preamble_state = 1
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elif self.preamble_state == 1:
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self.preamble.append(self.get_pulse_type())
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self.preamble_state = 2
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elif self.preamble_state == 2:
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self.preamble.append(self.get_pulse_type())
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self.preamble_state = 0
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self.state = 'DECODE STREAM'
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if self.preamble == [2, 0, 1, 0]:
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self.puty([1, ['Preamble W', 'W']])
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elif self.preamble == [2, 2, 1, 1]:
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self.puty([1, ['Preamble M', 'M']])
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elif self.preamble == [2, 1, 1, 2]:
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self.puty([1, ['Preamble B', 'B']])
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else:
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self.puty([1, ['Unknown Preamble', 'Unknown Prea.', 'U']])
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self.preamble = []
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self.seen_preamble = True
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self.bitcount = 0
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self.first_one = True
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self.last_preamble = self.samplenum
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def decode(self):
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if not self.samplerate:
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raise SamplerateError('Cannot decode without samplerate.')
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# Throw away first detected edge as it might be mangled data.
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self.wait({0: 'e'})
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while True:
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# Wait for any edge (rising or falling).
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(data,) = self.wait({0: 'e'})
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self.pulse_width = self.samplenum - self.samplenum_prev_edge - 1
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self.samplenum_prev_edge = self.samplenum
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if self.state == 'GET FIRST PULSE WIDTH':
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self.find_first_pulse_width()
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elif self.state == 'GET SECOND PULSE WIDTH':
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self.find_second_pulse_width()
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elif self.state == 'GET THIRD PULSE WIDTH':
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self.find_third_pulse_width()
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elif self.state == 'DECODE STREAM':
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self.decode_stream()
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elif self.state == 'DECODE PREAMBLE':
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self.decode_preamble()
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