diff options
Diffstat (limited to 'decoders/tdm_audio')
| -rw-r--r-- | decoders/tdm_audio/__init__.py | 25 | ||||
| -rw-r--r-- | decoders/tdm_audio/pd.py | 115 |
2 files changed, 140 insertions, 0 deletions
diff --git a/decoders/tdm_audio/__init__.py b/decoders/tdm_audio/__init__.py new file mode 100644 index 0000000..a95e16e --- /dev/null +++ b/decoders/tdm_audio/__init__.py @@ -0,0 +1,25 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2019 Ben Dooks <ben.dooks@codethink.co.uk> +## +## 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/>. +## + +''' +TDM Audio is an audio serial bus for moving audio data between devices +(usually on the same board) which can carry one or more channels of data. +''' + +from .pd import Decoder diff --git a/decoders/tdm_audio/pd.py b/decoders/tdm_audio/pd.py new file mode 100644 index 0000000..9c57d7a --- /dev/null +++ b/decoders/tdm_audio/pd.py @@ -0,0 +1,115 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2019 Ben Dooks <ben.dooks@codethink.co.uk> +## +## 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 + +MAX_CHANNELS = 8 + +class Decoder(srd.Decoder): + api_version = 3 + id = 'tdm_audio' + name = 'TDM audio' + longname = 'Time division multiplex audio' + desc = 'TDM multi-channel audio protocol.' + license = 'gplv2+' + inputs = ['logic'] + outputs = [] + tags = ['Audio'] + channels = ( + { 'id': 'clock', 'name': 'Bitclk', 'desc': 'Data bit clock' }, + { 'id': 'frame', 'name': 'Framesync', 'desc': 'Frame sync' }, + { 'id': 'data', 'name': 'Data', 'desc': 'Serial data' }, + ) + options = ( + {'id': 'bps', 'desc': 'Bits per sample', 'default': 16 }, + {'id': 'channels', 'desc': 'Channels per frame', 'default': MAX_CHANNELS }, + {'id': 'edge', 'desc': 'Clock edge to sample on', 'default': 'rising', 'values': ('rising', 'falling') } + ) + annotations = tuple(('ch%d' % i, 'Ch%d' % i) for i in range(MAX_CHANNELS)) + + def __init__(self): + self.reset() + + def reset(self): + self.samplerate = None + self.channels = MAX_CHANNELS + self.channel = 0 + self.bitdepth = 16 + self.bitcount = 0 + self.samplecount = 0 + self.lastsync = 0 + self.lastframe = 0 + self.data = 0 + self.ss_block = None + + def metdatadata(self, key, value): + if key == srd.SRD_CONF_SAMPLERATE: + self.samplerate = value + + def start(self): + self.out_ann = self.register(srd.OUTPUT_ANN) + self.bitdepth = self.options['bps'] + self.edge = self.options['edge'] + + def decode(self): + while True: + # Wait for edge of clock (sample on rising/falling edge). + clock, frame, data = self.wait({0: self.edge[0]}) + + self.data = (self.data << 1) | data + self.bitcount += 1 + + if self.ss_block is not None: + if self.bitcount >= self.bitdepth: + self.bitcount = 0 + self.channel += 1 + + c1 = 'Channel %d' % self.channel + c2 = 'C%d' % self.channel + c3 = '%d' % self.channel + if self.bitdepth <= 8: + v = '%02x' % self.data + elif self.bitdepth <= 16: + v = '%04x' % self.data + else: + v = '%08x' % self.data + + if self.channel < self.channels: + ch = self.channel + else: + ch = 0 + + self.put(self.ss_block, self.samplenum, self.out_ann, + [ch, ['%s: %s' % (c1, v), '%s: %s' % (c2, v), + '%s: %s' % (c3, v)]]) + self.data = 0 + self.ss_block = self.samplenum + self.samplecount += 1 + + # Check for new frame. + # Note, frame may be a single clock, or active for the first + # sample in the frame. + if frame != self.lastframe and frame == 1: + self.channel = 0 + self.bitcount = 0 + self.data = 0 + if self.ss_block is None: + self.ss_block = 0 + + self.lastframe = frame |