## ## This file is part of the libsigrokdecode project. ## ## Copyright (C) 2014 Guenther Wenninger ## ## 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 = 3 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 puty(self, data): self.put(self.ss_edge, self.samplenum, self.out_ann, data) def __init__(self): self.state = 'GET FIRST PULSE WIDTH' self.ss_edge = None self.first_edge = True self.samplenum_prev_edge = 0 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) # Assume that the initial pin state is logic 0. self.initial_pins = [0] def metadata(self, key, value): if key == srd.SRD_CONF_SAMPLERATE: self.samplerate = value def get_pulse_type(self): if self.range1 == 0 or self.range2 == 0: return -1 if self.pulse_width >= self.range2: return 2 elif self.pulse_width >= self.range1: return 0 else: return 1 def find_first_pulse_width(self): if self.pulse_width != 0: self.clocks.append(self.pulse_width) self.state = 'GET SECOND PULSE WIDTH' def find_second_pulse_width(self): 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 = 'GET THIRD PULSE WIDTH' def find_third_pulse_width(self): if not ((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))): return 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.puty([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 = 'DECODE STREAM' def decode_stream(self): pulse = self.get_pulse_type() if not self.seen_preamble: # This is probably the start of a preamble, decode it. if pulse == 2: self.preamble.append(self.get_pulse_type()) self.state = 'DECODE PREAMBLE' self.ss_edge = self.samplenum - self.pulse_width - 1 return # We've seen a 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 def decode_preamble(self): if self.preamble_state == 0: self.preamble.append(self.get_pulse_type()) self.preamble_state = 1 elif self.preamble_state == 1: self.preamble.append(self.get_pulse_type()) self.preamble_state = 2 elif self.preamble_state == 2: self.preamble.append(self.get_pulse_type()) self.preamble_state = 0 self.state = 'DECODE STREAM' if self.preamble == [2, 0, 1, 0]: self.puty([1, ['Preamble W', 'W']]) elif self.preamble == [2, 2, 1, 1]: self.puty([1, ['Preamble M', 'M']]) elif self.preamble == [2, 1, 1, 2]: self.puty([1, ['Preamble B', 'B']]) else: self.puty([1, ['Unknown Preamble', 'Unknown Prea.', 'U']]) self.preamble = [] self.seen_preamble = True self.bitcount = 0 self.first_one = True self.last_preamble = self.samplenum def decode(self): if not self.samplerate: raise SamplerateError('Cannot decode without samplerate.') # Throw away first detected edge as it might be mangled data. self.wait({0: 'e'}) while True: # Wait for any edge (rising or falling). (data,) = self.wait({0: 'e'}) self.pulse_width = self.samplenum - self.samplenum_prev_edge - 1 self.samplenum_prev_edge = self.samplenum if self.state == 'GET FIRST PULSE WIDTH': self.find_first_pulse_width() elif self.state == 'GET SECOND PULSE WIDTH': self.find_second_pulse_width() elif self.state == 'GET THIRD PULSE WIDTH': self.find_third_pulse_width() elif self.state == 'DECODE STREAM': self.decode_stream() elif self.state == 'DECODE PREAMBLE': self.decode_preamble()