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##
## 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))
annotation_rows = tuple(('ch%d' % i, 'Ch%d' % i, (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
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