--- /dev/null
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2014 Guenther Wenninger <robin@bitschubbser.org>
+##
+## 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, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+##
+
+import sigrokdecode as srd
+
+class SamplerateError(Exception):
+ pass
+
+class Decoder(srd.Decoder):
+ api_version = 2
+ id = 'spdif'
+ name = 'S/PDIF'
+ longname = 'Sony/Philips Digital Interface Format'
+ desc = 'Serial bus for connecting digital audio devices.'
+ license = 'gplv2+'
+ inputs = ['logic']
+ outputs = ['spdif']
+ channels = (
+ {'id': 'data', 'name': 'Data', 'desc': 'Data line'},
+ )
+ annotations = (
+ ('bitrate', 'Bitrate / baudrate'),
+ ('preamble', 'Preamble'),
+ ('bits', 'Bits'),
+ ('aux', 'Auxillary-audio-databits'),
+ ('samples', 'Audio Samples'),
+ ('validity', 'Data Valid'),
+ ('subcode', 'Subcode data'),
+ ('chan_stat', 'Channnel Status'),
+ ('parity', 'Parity Bit'),
+ )
+ annotation_rows = (
+ ('info', 'Info', (0, 1, 3, 5, 6, 7, 8)),
+ ('bits', 'Bits', (2,)),
+ ('samples', 'Samples', (4,)),
+ )
+
+ def putx(self, ss, es, data):
+ self.put(ss, es, self.out_ann, data)
+
+ def __init__(self, **kwargs):
+ self.state = 0
+ self.olddata = None
+ self.ss_edge = None
+ self.first_edge = True
+ self.pulse_width = 0
+
+ self.clocks = []
+ self.range1 = 0
+ self.range2 = 0
+
+ self.preamble_state = 0
+ self.preamble = []
+ self.seen_preamble = False
+ self.last_preamble = 0
+
+ self.first_one = True
+ self.subframe = []
+
+ 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
+
+ def get_pulse_type(self, pulse):
+ if self.range1 == 0 or self.range2 == 0:
+ return -1
+ if pulse >= self.range2:
+ return 2
+ elif pulse >= self.range1:
+ return 0
+ else:
+ return 1
+
+ def decode(self, ss, es, data):
+ if not self.samplerate:
+ raise SamplerateError('Cannot decode without samplerate.')
+
+ for (self.samplenum, pins) in data:
+ data = pins[0]
+
+ # Initialize first self.olddata with the first sample value.
+ if self.olddata == None:
+ self.olddata = data
+ continue
+
+ # First we need to recover the clock.
+ if self.olddata == data:
+ self.pulse_width += 1
+ else:
+ # Found rising or falling edge.
+ if self.first_edge:
+ # Throw away first detected edge as it might be mangled data.
+ self.first_edge = False
+ self.pulse_width = 0
+ else:
+ if self.state == 0:
+ # Find first pulse width.
+ if self.pulse_width != 0:
+ self.clocks.append(self.pulse_width)
+ self.state = 1
+
+ elif self.state == 1:
+ # Find second pulse width.
+ if self.pulse_width > (self.clocks[0] * 1.3) or self.pulse_width < (self.clocks[0] * 0.7):
+ self.clocks.append(self.pulse_width)
+ self.state = 2
+
+ elif self.state == 2:
+ # Find third pulse width.
+ if (self.pulse_width > (self.clocks[0] * 1.3) or self.pulse_width < (self.clocks[0] * 0.7)) \
+ and (self.pulse_width > (self.clocks[1] * 1.3) or self.pulse_width < (self.clocks[1] * 0.7)):
+ self.clocks.append(self.pulse_width)
+ self.clocks.sort()
+ self.range1 = (self.clocks[0] + self.clocks[1]) / 2
+ self.range2 = (self.clocks[1] + self.clocks[2]) / 2
+ spdif_bitrate = int(self.samplerate / (self.clocks[2] / 1.5))
+ self.ss_edge = 0
+
+ self.putx(self.ss_edge, self.samplenum, [0, \
+ ['Signal Bitrate: %d Mbit/s (=> %d kHz)' % \
+ (spdif_bitrate, (spdif_bitrate/ (2 * 32)))]])
+
+ clock_period_nsec = 1000000000 / spdif_bitrate
+
+ self.last_preamble = self.samplenum
+ # We are done recovering the clock, now let's decode the data stream.
+ self.state = 3
+
+ elif self.state == 3:
+ # Decode the stream.
+ pulse = self.get_pulse_type(self.pulse_width)
+
+ if self.seen_preamble:
+ if pulse == 1 and self.first_one:
+ self.first_one = False
+ self.subframe.append([pulse, self.samplenum - self.pulse_width - 1, self.samplenum])
+ elif pulse == 1 and not self.first_one:
+ self.subframe[-1][2] = self.samplenum
+ self.putx(self.subframe[-1][1], self.samplenum, [2, ['1']])
+ self.bitcount += 1
+ self.first_one = True
+ else:
+ self.subframe.append([pulse, self.samplenum - self.pulse_width - 1, self.samplenum])
+ self.putx(self.samplenum - self.pulse_width - 1, self.samplenum, [2, ['0']])
+ self.bitcount += 1
+
+ if self.bitcount == 28:
+ aux_audio_data = self.subframe[0:4]
+ sam, sam_rot = '', ''
+ for a in aux_audio_data:
+ sam = sam + str(a[0])
+ sam_rot = str(a[0]) + sam_rot
+ sample = self.subframe[4:24]
+ for s in sample:
+ sam = sam + str(s[0])
+ sam_rot = str(s[0]) + sam_rot
+ validity = self.subframe[24:25]
+ subcode_data = self.subframe[25:26]
+ channel_status = self.subframe[26:27]
+ parity = self.subframe[27:28]
+
+ self.putx(aux_audio_data[0][1], aux_audio_data[3][2], \
+ [3, ['Aux 0x%x' % int(sam, 2), '0x%x' % int(sam, 2)]])
+ self.putx(sample[0][1], sample[19][2], \
+ [3, ['Sample 0x%x' % int(sam, 2), '0x%x' % int(sam, 2)]])
+ self.putx(aux_audio_data[0][1], sample[19][2], \
+ [4, ['Audio 0x%x' % int(sam_rot, 2), '0x%x' % int(sam_rot, 2)]])
+ if validity[0][0] == 0:
+ self.putx(validity[0][1], validity[0][2], [5, ['V']])
+ else:
+ self.putx(validity[0][1], validity[0][2], [5, ['E']])
+ self.putx(subcode_data[0][1], subcode_data[0][2], [6, ['S: %d' % subcode_data[0][0]]])
+ self.putx(channel_status[0][1], channel_status[0][2], [7, ['C: %d' % channel_status[0][0]]])
+ self.putx(parity[0][1], parity[0][2], [8, ['P: %d' % parity[0][0]]])
+
+ self.subframe = []
+ self.seen_preamble = False
+ self.bitcount = 0
+ else:
+ # This is probably the start of a preamble, so go
+ # ahead and decode it.
+ if pulse == 2:
+ self.preamble.append(self.get_pulse_type(self.pulse_width))
+ self.state = 4 # Decode a preamble.
+ self.ss_edge = self.samplenum - self.pulse_width - 1
+
+ elif self.state == 4:
+ if self.preamble_state == 0:
+ self.preamble.append(self.get_pulse_type(self.pulse_width))
+ self.preamble_state = 1
+ elif self.preamble_state == 1:
+ self.preamble.append(self.get_pulse_type(self.pulse_width))
+ self.preamble_state = 2
+ elif self.preamble_state == 2:
+ self.preamble.append(self.get_pulse_type(self.pulse_width))
+ self.preamble_state = 0
+ self.state = 3
+ if self.preamble == [2, 0, 1, 0]:
+ self.putx(self.ss_edge, self.samplenum, [1, ['Preamble W', 'W']])
+ elif self.preamble == [2, 2, 1, 1]:
+ self.putx(self.ss_edge, self.samplenum, [1, ['Preamble M', 'M']])
+ elif self.preamble == [2, 1, 1, 2]:
+ self.putx(self.ss_edge, self.samplenum, [1, ['Preamble B', 'B']])
+ else:
+ self.putx(self.ss_edge, self.samplenum, [1, ['Unknown Preamble', 'Unkown Prea.', 'U']])
+ self.preamble = []
+ self.seen_preamble = True
+ self.bitcount = 0
+ self.first_one = True
+
+ self.last_preamble = self.samplenum
+
+ self.pulse_width = 0
+
+ self.olddata = data
+
projects / libsigrokdecode.git / commitdiff