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2ab416c2 | 1 | ## |
50bd5d25 | 2 | ## This file is part of the libsigrokdecode project. |
2ab416c2 JH |
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 | |
4539e9ca | 17 | ## along with this program; if not, see <http://www.gnu.org/licenses/>. |
2ab416c2 JH |
18 | ## |
19 | ||
2ab416c2 | 20 | import sigrokdecode as srd |
7f214f53 | 21 | import struct |
2ab416c2 | 22 | |
4adb11a9 | 23 | ''' |
c515eed7 | 24 | OUTPUT_PYTHON format: |
4adb11a9 UH |
25 | |
26 | Packet: | |
27 | [<ptype>, <pdata>] | |
28 | ||
29 | <ptype>, <pdata>: | |
30 | - 'DATA', [<channel>, <value>] | |
31 | ||
32 | <channel>: 'L' or 'R' | |
33 | <value>: integer | |
34 | ''' | |
35 | ||
21cda951 UH |
36 | class SamplerateError(Exception): |
37 | pass | |
38 | ||
2ab416c2 | 39 | class Decoder(srd.Decoder): |
07e40f34 | 40 | api_version = 3 |
2ab416c2 | 41 | id = 'i2s' |
270a59d8 | 42 | name = 'I²S' |
2ab416c2 | 43 | longname = 'Integrated Interchip Sound' |
a465436e | 44 | desc = 'Serial bus for connecting digital audio devices.' |
2ab416c2 JH |
45 | license = 'gplv2+' |
46 | inputs = ['logic'] | |
47 | outputs = ['i2s'] | |
6a15597a | 48 | channels = ( |
2ab416c2 JH |
49 | {'id': 'sck', 'name': 'SCK', 'desc': 'Bit clock line'}, |
50 | {'id': 'ws', 'name': 'WS', 'desc': 'Word select line'}, | |
ee3e279c | 51 | {'id': 'sd', 'name': 'SD', 'desc': 'Serial data line'}, |
da9bcbd9 BV |
52 | ) |
53 | annotations = ( | |
54 | ('left', 'Left channel'), | |
55 | ('right', 'Right channel'), | |
56 | ('warnings', 'Warnings'), | |
57 | ) | |
e54f222c UH |
58 | binary = ( |
59 | ('wav', 'WAV file'), | |
60 | ) | |
2ab416c2 | 61 | |
92b7b49f | 62 | def __init__(self): |
10aeb8ea GS |
63 | self.reset() |
64 | ||
65 | def reset(self): | |
f372d597 | 66 | self.samplerate = None |
2ab416c2 JH |
67 | self.oldws = 1 |
68 | self.bitcount = 0 | |
69 | self.data = 0 | |
70 | self.samplesreceived = 0 | |
780a5bee | 71 | self.first_sample = None |
486b19ce | 72 | self.ss_block = None |
abbbd2ba | 73 | self.wordlength = -1 |
e54f222c | 74 | self.wrote_wav_header = False |
2ab416c2 | 75 | |
f372d597 | 76 | def start(self): |
c515eed7 | 77 | self.out_python = self.register(srd.OUTPUT_PYTHON) |
2f370328 | 78 | self.out_binary = self.register(srd.OUTPUT_BINARY) |
be465111 | 79 | self.out_ann = self.register(srd.OUTPUT_ANN) |
2ab416c2 | 80 | |
f372d597 BV |
81 | def metadata(self, key, value): |
82 | if key == srd.SRD_CONF_SAMPLERATE: | |
83 | self.samplerate = value | |
84 | ||
2b2b7c30 | 85 | def putpb(self, data): |
486b19ce | 86 | self.put(self.ss_block, self.samplenum, self.out_python, data) |
2b2b7c30 | 87 | |
e54f222c | 88 | def putbin(self, data): |
2f370328 | 89 | self.put(self.ss_block, self.samplenum, self.out_binary, data) |
e54f222c | 90 | |
2b2b7c30 | 91 | def putb(self, data): |
486b19ce | 92 | self.put(self.ss_block, self.samplenum, self.out_ann, data) |
2b2b7c30 | 93 | |
2ab416c2 | 94 | def report(self): |
780a5bee | 95 | |
ee3e279c | 96 | # Calculate the sample rate. |
780a5bee | 97 | samplerate = '?' |
486b19ce | 98 | if self.ss_block is not None and \ |
35b380b1 | 99 | self.first_sample is not None and \ |
486b19ce | 100 | self.ss_block > self.first_sample: |
ee3e279c | 101 | samplerate = '%d' % (self.samplesreceived * |
486b19ce | 102 | self.samplerate / (self.ss_block - |
780a5bee JH |
103 | self.first_sample)) |
104 | ||
ea48f543 | 105 | return 'I²S: %d %d-bit samples received at %sHz' % \ |
780a5bee | 106 | (self.samplesreceived, self.wordlength, samplerate) |
2ab416c2 | 107 | |
e54f222c UH |
108 | def wav_header(self): |
109 | # Chunk descriptor | |
110 | h = b'RIFF' | |
111 | h += b'\x24\x80\x00\x00' # Chunk size (2084) | |
112 | h += b'WAVE' | |
113 | # Fmt subchunk | |
114 | h += b'fmt ' | |
115 | h += b'\x10\x00\x00\x00' # Subchunk size (16 bytes) | |
116 | h += b'\x01\x00' # Audio format (0x0001 == PCM) | |
117 | h += b'\x02\x00' # Number of channels (2) | |
118 | h += b'\x80\x3e\x00\x00' # Samplerate (16000) | |
7f214f53 | 119 | h += b'\x00\xfa\x00\x00' # Byterate (64000) |
e54f222c | 120 | h += b'\x04\x00' # Blockalign (4) |
7f214f53 | 121 | h += b'\x20\x00' # Bits per sample (32) |
e54f222c UH |
122 | # Data subchunk |
123 | h += b'data' | |
65658c0a | 124 | h += b'\xff\xff\xff\xff' # Subchunk size (4G bytes) TODO |
e54f222c UH |
125 | return h |
126 | ||
127 | def wav_sample(self, sample): | |
30c855f6 | 128 | return struct.pack('<I', self.data) |
e54f222c | 129 | |
07e40f34 | 130 | def decode(self): |
21cda951 UH |
131 | if not self.samplerate: |
132 | raise SamplerateError('Cannot decode without samplerate.') | |
07e40f34 UH |
133 | while True: |
134 | # Wait for a rising edge on the SCK pin. | |
135 | sck, ws, sd = self.wait({0: 'r'}) | |
2ab416c2 JH |
136 | |
137 | self.data = (self.data << 1) | sd | |
138 | self.bitcount += 1 | |
139 | ||
ee3e279c | 140 | # This was not the LSB unless WS has flipped. |
2ab416c2 JH |
141 | if ws == self.oldws: |
142 | continue | |
143 | ||
ee3e279c | 144 | # Only submit the sample, if we received the beginning of it. |
486b19ce | 145 | if self.ss_block is not None: |
e54f222c UH |
146 | |
147 | if not self.wrote_wav_header: | |
2f370328 | 148 | self.put(0, 0, self.out_binary, [0, self.wav_header()]) |
e54f222c UH |
149 | self.wrote_wav_header = True |
150 | ||
2ab416c2 | 151 | self.samplesreceived += 1 |
750a808a UH |
152 | |
153 | idx = 0 if self.oldws else 1 | |
154 | c1 = 'Left channel' if self.oldws else 'Right channel' | |
155 | c2 = 'Left' if self.oldws else 'Right' | |
156 | c3 = 'L' if self.oldws else 'R' | |
157 | v = '%08x' % self.data | |
158 | self.putpb(['DATA', [c3, self.data]]) | |
159 | self.putb([idx, ['%s: %s' % (c1, v), '%s: %s' % (c2, v), | |
160 | '%s: %s' % (c3, v), c3]]) | |
2824e811 | 161 | self.putbin([0, self.wav_sample(self.data)]) |
abbbd2ba | 162 | |
ee3e279c | 163 | # Check that the data word was the correct length. |
abbbd2ba | 164 | if self.wordlength != -1 and self.wordlength != self.bitcount: |
2b2b7c30 UH |
165 | self.putb([2, ['Received %d-bit word, expected %d-bit ' |
166 | 'word' % (self.bitcount, self.wordlength)]]) | |
abbbd2ba JH |
167 | |
168 | self.wordlength = self.bitcount | |
2ab416c2 JH |
169 | |
170 | # Reset decoder state. | |
171 | self.data = 0 | |
172 | self.bitcount = 0 | |
486b19ce | 173 | self.ss_block = self.samplenum |
780a5bee | 174 | |
ee3e279c | 175 | # Save the first sample position. |
35b380b1 | 176 | if self.first_sample is None: |
2b2b7c30 | 177 | self.first_sample = self.samplenum |
780a5bee | 178 | |
2ab416c2 | 179 | self.oldws = ws |