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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 | |
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 | ||
2ab416c2 JH |
21 | import sigrokdecode as srd |
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 | ||
2ab416c2 JH |
36 | class Decoder(srd.Decoder): |
37 | api_version = 1 | |
38 | id = 'i2s' | |
270a59d8 | 39 | name = 'I²S' |
2ab416c2 | 40 | longname = 'Integrated Interchip Sound' |
a465436e | 41 | desc = 'Serial bus for connecting digital audio devices.' |
2ab416c2 JH |
42 | license = 'gplv2+' |
43 | inputs = ['logic'] | |
44 | outputs = ['i2s'] | |
45 | probes = [ | |
46 | {'id': 'sck', 'name': 'SCK', 'desc': 'Bit clock line'}, | |
47 | {'id': 'ws', 'name': 'WS', 'desc': 'Word select line'}, | |
ee3e279c | 48 | {'id': 'sd', 'name': 'SD', 'desc': 'Serial data line'}, |
2ab416c2 JH |
49 | ] |
50 | annotations = [ | |
29fc3625 UH |
51 | ['left', 'Left channel'], |
52 | ['right', 'Right channel'], | |
53 | ['warnings', 'Warnings'], | |
2ab416c2 | 54 | ] |
e54f222c UH |
55 | binary = ( |
56 | ('wav', 'WAV file'), | |
57 | ) | |
2ab416c2 JH |
58 | |
59 | def __init__(self, **kwargs): | |
f372d597 | 60 | self.samplerate = None |
2ab416c2 JH |
61 | self.oldsck = 1 |
62 | self.oldws = 1 | |
63 | self.bitcount = 0 | |
64 | self.data = 0 | |
65 | self.samplesreceived = 0 | |
780a5bee | 66 | self.first_sample = None |
2ab416c2 | 67 | self.start_sample = None |
abbbd2ba | 68 | self.wordlength = -1 |
e54f222c | 69 | self.wrote_wav_header = False |
2ab416c2 | 70 | |
f372d597 | 71 | def start(self): |
c515eed7 | 72 | self.out_python = self.register(srd.OUTPUT_PYTHON) |
e54f222c | 73 | self.out_bin = self.register(srd.OUTPUT_BINARY) |
be465111 | 74 | self.out_ann = self.register(srd.OUTPUT_ANN) |
2ab416c2 | 75 | |
f372d597 BV |
76 | def metadata(self, key, value): |
77 | if key == srd.SRD_CONF_SAMPLERATE: | |
78 | self.samplerate = value | |
79 | ||
2b2b7c30 | 80 | def putpb(self, data): |
c515eed7 | 81 | self.put(self.start_sample, self.samplenum, self.out_python, data) |
2b2b7c30 | 82 | |
e54f222c UH |
83 | def putbin(self, data): |
84 | self.put(self.start_sample, self.samplenum, self.out_bin, data) | |
85 | ||
2b2b7c30 UH |
86 | def putb(self, data): |
87 | self.put(self.start_sample, self.samplenum, self.out_ann, data) | |
88 | ||
2ab416c2 | 89 | def report(self): |
780a5bee | 90 | |
ee3e279c | 91 | # Calculate the sample rate. |
780a5bee JH |
92 | samplerate = '?' |
93 | if self.start_sample != None and \ | |
94 | self.first_sample != None and \ | |
95 | self.start_sample > self.first_sample: | |
ee3e279c | 96 | samplerate = '%d' % (self.samplesreceived * |
780a5bee JH |
97 | self.samplerate / (self.start_sample - |
98 | self.first_sample)) | |
99 | ||
ea48f543 | 100 | return 'I²S: %d %d-bit samples received at %sHz' % \ |
780a5bee | 101 | (self.samplesreceived, self.wordlength, samplerate) |
2ab416c2 | 102 | |
e54f222c UH |
103 | def wav_header(self): |
104 | # Chunk descriptor | |
105 | h = b'RIFF' | |
106 | h += b'\x24\x80\x00\x00' # Chunk size (2084) | |
107 | h += b'WAVE' | |
108 | # Fmt subchunk | |
109 | h += b'fmt ' | |
110 | h += b'\x10\x00\x00\x00' # Subchunk size (16 bytes) | |
111 | h += b'\x01\x00' # Audio format (0x0001 == PCM) | |
112 | h += b'\x02\x00' # Number of channels (2) | |
113 | h += b'\x80\x3e\x00\x00' # Samplerate (16000) | |
114 | h += b'\x00\x7d\x00\x00' # Byterate (32000) | |
115 | h += b'\x04\x00' # Blockalign (4) | |
116 | h += b'\x10\x00' # Bits per sample (16) | |
117 | # Data subchunk | |
118 | h += b'data' | |
119 | h += b'\xff\xff\x00\x00' # Subchunk size (65535 bytes) TODO | |
120 | return h | |
121 | ||
122 | def wav_sample(self, sample): | |
123 | # TODO: This currently assumes U32 samples, and converts to S16. | |
124 | s = sample >> 16 | |
125 | if s >= 0x8000: | |
126 | s -= 0x10000 | |
127 | lo, hi = s & 0xff, (s >> 8) & 0xff | |
128 | return bytes([lo, hi]) | |
129 | ||
2ab416c2 | 130 | def decode(self, ss, es, data): |
f372d597 BV |
131 | if self.samplerate is None: |
132 | raise Exception("Cannot decode without samplerate.") | |
2b2b7c30 | 133 | for self.samplenum, (sck, ws, sd) in data: |
2ab416c2 JH |
134 | |
135 | # Ignore sample if the bit clock hasn't changed. | |
136 | if sck == self.oldsck: | |
137 | continue | |
138 | ||
139 | self.oldsck = sck | |
ee3e279c | 140 | if sck == 0: # Ignore the falling clock edge. |
2ab416c2 JH |
141 | continue |
142 | ||
143 | self.data = (self.data << 1) | sd | |
144 | self.bitcount += 1 | |
145 | ||
ee3e279c | 146 | # This was not the LSB unless WS has flipped. |
2ab416c2 JH |
147 | if ws == self.oldws: |
148 | continue | |
149 | ||
ee3e279c | 150 | # Only submit the sample, if we received the beginning of it. |
2ab416c2 | 151 | if self.start_sample != None: |
e54f222c UH |
152 | |
153 | if not self.wrote_wav_header: | |
154 | self.put(0, 0, self.out_bin, (0, self.wav_header())) | |
155 | self.wrote_wav_header = True | |
156 | ||
2ab416c2 | 157 | self.samplesreceived += 1 |
750a808a UH |
158 | |
159 | idx = 0 if self.oldws else 1 | |
160 | c1 = 'Left channel' if self.oldws else 'Right channel' | |
161 | c2 = 'Left' if self.oldws else 'Right' | |
162 | c3 = 'L' if self.oldws else 'R' | |
163 | v = '%08x' % self.data | |
164 | self.putpb(['DATA', [c3, self.data]]) | |
165 | self.putb([idx, ['%s: %s' % (c1, v), '%s: %s' % (c2, v), | |
166 | '%s: %s' % (c3, v), c3]]) | |
e54f222c | 167 | self.putbin((0, self.wav_sample(self.data))) |
abbbd2ba | 168 | |
ee3e279c | 169 | # Check that the data word was the correct length. |
abbbd2ba | 170 | if self.wordlength != -1 and self.wordlength != self.bitcount: |
2b2b7c30 UH |
171 | self.putb([2, ['Received %d-bit word, expected %d-bit ' |
172 | 'word' % (self.bitcount, self.wordlength)]]) | |
abbbd2ba JH |
173 | |
174 | self.wordlength = self.bitcount | |
2ab416c2 JH |
175 | |
176 | # Reset decoder state. | |
177 | self.data = 0 | |
178 | self.bitcount = 0 | |
2b2b7c30 | 179 | self.start_sample = self.samplenum |
780a5bee | 180 | |
ee3e279c | 181 | # Save the first sample position. |
780a5bee | 182 | if self.first_sample == None: |
2b2b7c30 | 183 | self.first_sample = self.samplenum |
780a5bee | 184 | |
2ab416c2 | 185 | self.oldws = ws |
ee3e279c | 186 |