[libsigrokdecode.git] / decoders / i2s / i2s.py

##
## This file is part of the sigrok project.
##
## Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.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, write to the Free Software
## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
##

# I2S protocol decoder

import sigrokdecode as srd

# Annotation formats
ANN_HEX = 0

class Decoder(srd.Decoder):
    api_version = 1
    id = 'i2s'
    name = 'I2S'
    longname = 'Integrated Interchip Sound'
    desc = 'Serial bus for connecting digital audio devices.'
    license = 'gplv2+'
    inputs = ['logic']
    outputs = ['i2s']
    probes = [
        {'id': 'sck', 'name': 'SCK', 'desc': 'Bit clock line'},
        {'id': 'ws', 'name': 'WS', 'desc': 'Word select line'},
        {'id': 'sd', 'name': 'SD', 'desc': 'Serial data line'},
    ]
    optional_probes = []
    options = {}
    annotations = [
        ['Hex', 'Annotations in hex format'],
    ]

    def __init__(self, **kwargs):
        self.oldsck = 1
        self.oldws = 1
        self.bitcount = 0
        self.data = 0
        self.samplesreceived = 0
        self.first_sample = None
        self.start_sample = None
        self.samplenum = -1
        self.wordlength = -1

    def start(self, metadata):
        self.samplerate = metadata['samplerate']
        self.out_proto = self.add(srd.OUTPUT_PROTO, 'i2s')
        self.out_ann = self.add(srd.OUTPUT_ANN, 'i2s')

    def report(self):

        # Calculate the sample rate.
        samplerate = '?'
        if self.start_sample != None and \
            self.first_sample != None and \
            self.start_sample > self.first_sample:
            samplerate = '%d' % (self.samplesreceived *
                self.samplerate / (self.start_sample -
                self.first_sample))

        return 'I2S: %d %d-bit samples received at %sHz' % \
            (self.samplesreceived, self.wordlength, samplerate)

    def decode(self, ss, es, data):
        for samplenum, (sck, ws, sd) in data:

            # Ignore sample if the bit clock hasn't changed.
            if sck == self.oldsck:
                continue

            self.oldsck = sck
            if sck == 0:   # Ignore the falling clock edge.
                continue

            self.data = (self.data << 1) | sd
            self.bitcount += 1

            # This was not the LSB unless WS has flipped.
            if ws == self.oldws:
                continue

            # Only submit the sample, if we received the beginning of it.
            if self.start_sample != None:
                self.samplesreceived += 1
                self.put(self.start_sample, self.samplenum, self.out_proto,
                         ['data', self.data])
                self.put(self.start_sample, self.samplenum, self.out_ann,
                         [ANN_HEX, ['%s: 0x%08x' % ('L' if self.oldws else 'R',
                         self.data)]])

                # Check that the data word was the correct length.
                if self.wordlength != -1 and self.wordlength != self.bitcount:
                    self.put(self.start_sample, self.samplenum, self.out_ann,
                        [ANN_HEX, ['WARNING: Received a %d-bit word, when a '
                        '%d-bit word was expected' % (self.bitcount,
                        self.wordlength)]])

                self.wordlength = self.bitcount

            # Reset decoder state.
            self.data = 0
            self.bitcount = 0
            self.start_sample = self.samplenum

            # Save the first sample position.
            if self.first_sample == None:
                self.first_sample = self.samplenum

            self.oldws = ws
Commit	Line	Data
	1	##
	2	## This file is part of the sigrok project.
	3	##
	4	## Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
	5	##
	6	## This program is free software; you can redistribute it and/or modify
	7	## it under the terms of the GNU General Public License as published by
	8	## the Free Software Foundation; either version 2 of the License, or
	9	## (at your option) any later version.
	10	##
	11	## This program is distributed in the hope that it will be useful,
	12	## but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	## GNU General Public License for more details.
	15	##
	16	## You should have received a copy of the GNU General Public License
	17	## along with this program; if not, write to the Free Software
	18	## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	19	##
	20
	21	# I2S protocol decoder
	22
	23	import sigrokdecode as srd
	24
	25	# Annotation formats
	26	ANN_HEX = 0
	27
	28	class Decoder(srd.Decoder):
	29	api_version = 1
	30	id = 'i2s'
	31	name = 'I2S'
	32	longname = 'Integrated Interchip Sound'
	33	desc = 'Serial bus for connecting digital audio devices.'
	34	license = 'gplv2+'
	35	inputs = ['logic']
	36	outputs = ['i2s']
	37	probes = [
	38	{'id': 'sck', 'name': 'SCK', 'desc': 'Bit clock line'},
	39	{'id': 'ws', 'name': 'WS', 'desc': 'Word select line'},
	40	{'id': 'sd', 'name': 'SD', 'desc': 'Serial data line'},
	41	]
	42	optional_probes = []
	43	options = {}
	44	annotations = [
	45	['Hex', 'Annotations in hex format'],
	46	]
	47
	48	def __init__(self, **kwargs):
	49	self.oldsck = 1
	50	self.oldws = 1
	51	self.bitcount = 0
	52	self.data = 0
	53	self.samplesreceived = 0
	54	self.first_sample = None
	55	self.start_sample = None
	56	self.samplenum = -1
	57	self.wordlength = -1
	58
	59	def start(self, metadata):
	60	self.samplerate = metadata['samplerate']
	61	self.out_proto = self.add(srd.OUTPUT_PROTO, 'i2s')
	62	self.out_ann = self.add(srd.OUTPUT_ANN, 'i2s')
	63
	64	def report(self):
	65
	66	# Calculate the sample rate.
	67	samplerate = '?'
	68	if self.start_sample != None and \
	69	self.first_sample != None and \
	70	self.start_sample > self.first_sample:
	71	samplerate = '%d' % (self.samplesreceived *
	72	self.samplerate / (self.start_sample -
	73	self.first_sample))
	74
	75	return 'I2S: %d %d-bit samples received at %sHz' % \
	76	(self.samplesreceived, self.wordlength, samplerate)
	77
	78	def decode(self, ss, es, data):
	79	for samplenum, (sck, ws, sd) in data:
	80
	81	# Ignore sample if the bit clock hasn't changed.
	82	if sck == self.oldsck:
	83	continue
	84
	85	self.oldsck = sck
	86	if sck == 0: # Ignore the falling clock edge.
	87	continue
	88
	89	self.data = (self.data << 1) \| sd
	90	self.bitcount += 1
	91
	92	# This was not the LSB unless WS has flipped.
	93	if ws == self.oldws:
	94	continue
	95
	96	# Only submit the sample, if we received the beginning of it.
	97	if self.start_sample != None:
	98	self.samplesreceived += 1
	99	self.put(self.start_sample, self.samplenum, self.out_proto,
	100	['data', self.data])
	101	self.put(self.start_sample, self.samplenum, self.out_ann,
	102	[ANN_HEX, ['%s: 0x%08x' % ('L' if self.oldws else 'R',
	103	self.data)]])
	104
	105	# Check that the data word was the correct length.
	106	if self.wordlength != -1 and self.wordlength != self.bitcount:
	107	self.put(self.start_sample, self.samplenum, self.out_ann,
	108	[ANN_HEX, ['WARNING: Received a %d-bit word, when a '
	109	'%d-bit word was expected' % (self.bitcount,
	110	self.wordlength)]])
	111
	112	self.wordlength = self.bitcount
	113
	114	# Reset decoder state.
	115	self.data = 0
	116	self.bitcount = 0
	117	self.start_sample = self.samplenum
	118
	119	# Save the first sample position.
	120	if self.first_sample == None:
	121	self.first_sample = self.samplenum
	122
	123	self.oldws = ws
	124