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

##
## This file is part of the libsigrokdecode 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

'''
Protocol output format:

Packet:
[<ptype>, <pdata>]

<ptype>, <pdata>:
 - 'DATA', [<channel>, <value>]

<channel>: 'L' or 'R'
<value>: integer
'''

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 = [
        ['left', 'Left channel'],
        ['right', 'Right channel'],
        ['warnings', 'Warnings'],
    ]
    binary = (
        ('wav', 'WAV file'),
    )

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

    def start(self):
        self.out_proto = self.register(srd.OUTPUT_PYTHON)
        self.out_bin = self.register(srd.OUTPUT_BINARY)
        self.out_ann = self.register(srd.OUTPUT_ANN)

    def metadata(self, key, value):
        if key == srd.SRD_CONF_SAMPLERATE:
            self.samplerate = value

    def putpb(self, data):
        self.put(self.start_sample, self.samplenum, self.out_proto, data)

    def putbin(self, data):
        self.put(self.start_sample, self.samplenum, self.out_bin, data)

    def putb(self, data):
        self.put(self.start_sample, self.samplenum, self.out_ann, data)

    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 wav_header(self):
        # Chunk descriptor
        h  = b'RIFF'
        h += b'\x24\x80\x00\x00' # Chunk size (2084)
        h += b'WAVE'
        # Fmt subchunk
        h += b'fmt '
        h += b'\x10\x00\x00\x00' # Subchunk size (16 bytes)
        h += b'\x01\x00'         # Audio format (0x0001 == PCM)
        h += b'\x02\x00'         # Number of channels (2)
        h += b'\x80\x3e\x00\x00' # Samplerate (16000)
        h += b'\x00\x7d\x00\x00' # Byterate (32000)
        h += b'\x04\x00'         # Blockalign (4)
        h += b'\x10\x00'         # Bits per sample (16)
        # Data subchunk
        h += b'data'
        h += b'\xff\xff\x00\x00' # Subchunk size (65535 bytes) TODO
        return h

    def wav_sample(self, sample):
        # TODO: This currently assumes U32 samples, and converts to S16.
        s = sample >> 16
        if s >= 0x8000:
            s -= 0x10000
        lo, hi = s & 0xff, (s >> 8) & 0xff
        return bytes([lo, hi])

    def decode(self, ss, es, data):
        if self.samplerate is None:
            raise Exception("Cannot decode without samplerate.")
        for self.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:

                if not self.wrote_wav_header:
                    self.put(0, 0, self.out_bin, (0, self.wav_header()))
                    self.wrote_wav_header = True

                self.samplesreceived += 1

                idx = 0 if self.oldws else 1
                c1 = 'Left channel' if self.oldws else 'Right channel'
                c2 = 'Left' if self.oldws else 'Right'
                c3 = 'L' if self.oldws else 'R'
                v = '%08x' % self.data
                self.putpb(['DATA', [c3, self.data]])
                self.putb([idx, ['%s: %s' % (c1, v), '%s: %s' % (c2, v),
                                 '%s: %s' % (c3, v), c3]])
                self.putbin((0, self.wav_sample(self.data)))

                # Check that the data word was the correct length.
                if self.wordlength != -1 and self.wordlength != self.bitcount:
                    self.putb([2, ['Received %d-bit word, expected %d-bit '
                                   'word' % (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 libsigrokdecode 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	'''
	26	Protocol output format:
	27
	28	Packet:
	29	[<ptype>, <pdata>]
	30
	31	<ptype>, <pdata>:
	32	- 'DATA', [<channel>, <value>]
	33
	34	<channel>: 'L' or 'R'
	35	<value>: integer
	36	'''
	37
	38	class Decoder(srd.Decoder):
	39	api_version = 1
	40	id = 'i2s'
	41	name = 'I²S'
	42	longname = 'Integrated Interchip Sound'
	43	desc = 'Serial bus for connecting digital audio devices.'
	44	license = 'gplv2+'
	45	inputs = ['logic']
	46	outputs = ['i2s']
	47	probes = [
	48	{'id': 'sck', 'name': 'SCK', 'desc': 'Bit clock line'},
	49	{'id': 'ws', 'name': 'WS', 'desc': 'Word select line'},
	50	{'id': 'sd', 'name': 'SD', 'desc': 'Serial data line'},
	51	]
	52	optional_probes = []
	53	options = {}
	54	annotations = [
	55	['left', 'Left channel'],
	56	['right', 'Right channel'],
	57	['warnings', 'Warnings'],
	58	]
	59	binary = (
	60	('wav', 'WAV file'),
	61	)
	62
	63	def __init__(self, **kwargs):
	64	self.samplerate = None
	65	self.oldsck = 1
	66	self.oldws = 1
	67	self.bitcount = 0
	68	self.data = 0
	69	self.samplesreceived = 0
	70	self.first_sample = None
	71	self.start_sample = None
	72	self.wordlength = -1
	73	self.wrote_wav_header = False
	74
	75	def start(self):
	76	self.out_proto = self.register(srd.OUTPUT_PYTHON)
	77	self.out_bin = self.register(srd.OUTPUT_BINARY)
	78	self.out_ann = self.register(srd.OUTPUT_ANN)
	79
	80	def metadata(self, key, value):
	81	if key == srd.SRD_CONF_SAMPLERATE:
	82	self.samplerate = value
	83
	84	def putpb(self, data):
	85	self.put(self.start_sample, self.samplenum, self.out_proto, data)
	86
	87	def putbin(self, data):
	88	self.put(self.start_sample, self.samplenum, self.out_bin, data)
	89
	90	def putb(self, data):
	91	self.put(self.start_sample, self.samplenum, self.out_ann, data)
	92
	93	def report(self):
	94
	95	# Calculate the sample rate.
	96	samplerate = '?'
	97	if self.start_sample != None and \
	98	self.first_sample != None and \
	99	self.start_sample > self.first_sample:
	100	samplerate = '%d' % (self.samplesreceived *
	101	self.samplerate / (self.start_sample -
	102	self.first_sample))
	103
	104	return 'I²S: %d %d-bit samples received at %sHz' % \
	105	(self.samplesreceived, self.wordlength, samplerate)
	106
	107	def wav_header(self):
	108	# Chunk descriptor
	109	h = b'RIFF'
	110	h += b'\x24\x80\x00\x00' # Chunk size (2084)
	111	h += b'WAVE'
	112	# Fmt subchunk
	113	h += b'fmt '
	114	h += b'\x10\x00\x00\x00' # Subchunk size (16 bytes)
	115	h += b'\x01\x00' # Audio format (0x0001 == PCM)
	116	h += b'\x02\x00' # Number of channels (2)
	117	h += b'\x80\x3e\x00\x00' # Samplerate (16000)
	118	h += b'\x00\x7d\x00\x00' # Byterate (32000)
	119	h += b'\x04\x00' # Blockalign (4)
	120	h += b'\x10\x00' # Bits per sample (16)
	121	# Data subchunk
	122	h += b'data'
	123	h += b'\xff\xff\x00\x00' # Subchunk size (65535 bytes) TODO
	124	return h
	125
	126	def wav_sample(self, sample):
	127	# TODO: This currently assumes U32 samples, and converts to S16.
	128	s = sample >> 16
	129	if s >= 0x8000:
	130	s -= 0x10000
	131	lo, hi = s & 0xff, (s >> 8) & 0xff
	132	return bytes([lo, hi])
	133
	134	def decode(self, ss, es, data):
	135	if self.samplerate is None:
	136	raise Exception("Cannot decode without samplerate.")
	137	for self.samplenum, (sck, ws, sd) in data:
	138
	139	# Ignore sample if the bit clock hasn't changed.
	140	if sck == self.oldsck:
	141	continue
	142
	143	self.oldsck = sck
	144	if sck == 0: # Ignore the falling clock edge.
	145	continue
	146
	147	self.data = (self.data << 1) \| sd
	148	self.bitcount += 1
	149
	150	# This was not the LSB unless WS has flipped.
	151	if ws == self.oldws:
	152	continue
	153
	154	# Only submit the sample, if we received the beginning of it.
	155	if self.start_sample != None:
	156
	157	if not self.wrote_wav_header:
	158	self.put(0, 0, self.out_bin, (0, self.wav_header()))
	159	self.wrote_wav_header = True
	160
	161	self.samplesreceived += 1
	162
	163	idx = 0 if self.oldws else 1
	164	c1 = 'Left channel' if self.oldws else 'Right channel'
	165	c2 = 'Left' if self.oldws else 'Right'
	166	c3 = 'L' if self.oldws else 'R'
	167	v = '%08x' % self.data
	168	self.putpb(['DATA', [c3, self.data]])
	169	self.putb([idx, ['%s: %s' % (c1, v), '%s: %s' % (c2, v),
	170	'%s: %s' % (c3, v), c3]])
	171	self.putbin((0, self.wav_sample(self.data)))
	172
	173	# Check that the data word was the correct length.
	174	if self.wordlength != -1 and self.wordlength != self.bitcount:
	175	self.putb([2, ['Received %d-bit word, expected %d-bit '
	176	'word' % (self.bitcount, self.wordlength)]])
	177
	178	self.wordlength = self.bitcount
	179
	180	# Reset decoder state.
	181	self.data = 0
	182	self.bitcount = 0
	183	self.start_sample = self.samplenum
	184
	185	# Save the first sample position.
	186	if self.first_sample == None:
	187	self.first_sample = self.samplenum
	188
	189	self.oldws = ws
	190