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0588ed70 | 1 | ## |
50bd5d25 | 2 | ## This file is part of the libsigrokdecode project. |
0588ed70 | 3 | ## |
de038c47 | 4 | ## Copyright (C) 2010-2014 Uwe Hermann <uwe@hermann-uwe.de> |
0588ed70 UH |
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 | ||
0588ed70 | 21 | # TODO: Look into arbitration, collision detection, clock synchronisation, etc. |
9e95e4d8 | 22 | # TODO: Implement support for 10bit slave addresses. |
0588ed70 UH |
23 | # TODO: Implement support for inverting SDA/SCL levels (0->1 and 1->0). |
24 | # TODO: Implement support for detecting various bus errors. | |
23fb2e12 | 25 | |
677d597b | 26 | import sigrokdecode as srd |
b2c19614 | 27 | |
f1428c4c | 28 | ''' |
c515eed7 | 29 | OUTPUT_PYTHON format: |
f1428c4c | 30 | |
ab4aa33c | 31 | I²C packet: |
f1428c4c UH |
32 | [<cmd>, <data>] |
33 | ||
34 | <cmd> is one of: | |
35 | - 'START' (START condition) | |
36 | - 'START REPEAT' (Repeated START condition) | |
37 | - 'ADDRESS READ' (Slave address, read) | |
38 | - 'ADDRESS WRITE' (Slave address, write) | |
39 | - 'DATA READ' (Data, read) | |
40 | - 'DATA WRITE' (Data, write) | |
41 | - 'STOP' (STOP condition) | |
42 | - 'ACK' (ACK bit) | |
43 | - 'NACK' (NACK bit) | |
de038c47 | 44 | - 'BITS' (<data>: list of data/address bits and their ss/es numbers) |
f1428c4c UH |
45 | |
46 | <data> is the data or address byte associated with the 'ADDRESS*' and 'DATA*' | |
47 | command. Slave addresses do not include bit 0 (the READ/WRITE indication bit). | |
48 | For example, a slave address field could be 0x51 (instead of 0xa2). | |
49 | For 'START', 'START REPEAT', 'STOP', 'ACK', and 'NACK' <data> is None. | |
50 | ''' | |
51 | ||
d94ff143 | 52 | # CMD: [annotation-type-index, long annotation, short annotation] |
1541976f | 53 | proto = { |
d94ff143 UH |
54 | 'START': [0, 'Start', 'S'], |
55 | 'START REPEAT': [1, 'Start repeat', 'Sr'], | |
56 | 'STOP': [2, 'Stop', 'P'], | |
57 | 'ACK': [3, 'ACK', 'A'], | |
58 | 'NACK': [4, 'NACK', 'N'], | |
de038c47 UH |
59 | 'BIT': [5, 'Bit', 'B'], |
60 | 'ADDRESS READ': [6, 'Address read', 'AR'], | |
61 | 'ADDRESS WRITE': [7, 'Address write', 'AW'], | |
62 | 'DATA READ': [8, 'Data read', 'DR'], | |
63 | 'DATA WRITE': [9, 'Data write', 'DW'], | |
15969949 | 64 | } |
e5080882 | 65 | |
677d597b | 66 | class Decoder(srd.Decoder): |
a2c2afd9 | 67 | api_version = 1 |
67e847fd | 68 | id = 'i2c' |
ab4aa33c | 69 | name = 'I²C' |
9a12a6e7 | 70 | longname = 'Inter-Integrated Circuit' |
a465436e | 71 | desc = 'Two-wire, multi-master, serial bus.' |
f39d2404 UH |
72 | license = 'gplv2+' |
73 | inputs = ['logic'] | |
74 | outputs = ['i2c'] | |
bc5f5a43 BV |
75 | probes = [ |
76 | {'id': 'scl', 'name': 'SCL', 'desc': 'Serial clock line'}, | |
77 | {'id': 'sda', 'name': 'SDA', 'desc': 'Serial data line'}, | |
78 | ] | |
b77614bc | 79 | optional_probes = [] |
f39d2404 | 80 | options = { |
d94ff143 | 81 | 'address_format': ['Displayed slave address format', 'shifted'], |
ad2dc0de | 82 | } |
e97b6ef5 | 83 | annotations = [ |
fbd226c3 BV |
84 | ['start', 'Start condition'], |
85 | ['repeat-start', 'Repeat start condition'], | |
86 | ['stop', 'Stop condition'], | |
87 | ['ack', 'ACK'], | |
88 | ['nack', 'NACK'], | |
de038c47 | 89 | ['bit', 'Data/address bit'], |
fbd226c3 BV |
90 | ['address-read', 'Address read'], |
91 | ['address-write', 'Address write'], | |
92 | ['data-read', 'Data read'], | |
93 | ['data-write', 'Data write'], | |
94 | ['warnings', 'Human-readable warnings'], | |
15969949 | 95 | ] |
de038c47 UH |
96 | annotation_rows = ( |
97 | ('bits', 'Bits', (5,)), | |
98 | ('addr-data', 'Address/Data', (0, 1, 2, 3, 4, 6, 7, 8, 9)), | |
99 | ('warnings', 'Warnings', (10,)), | |
100 | ) | |
a929afa6 | 101 | binary = ( |
5cb2cb02 BV |
102 | ('address-read', 'Address read'), |
103 | ('address-write', 'Address write'), | |
104 | ('data-read', 'Data read'), | |
105 | ('data-write', 'Data write'), | |
a929afa6 | 106 | ) |
0588ed70 | 107 | |
3643fc3f | 108 | def __init__(self, **kwargs): |
8d2a9636 | 109 | self.samplerate = None |
de038c47 | 110 | self.ss = self.es = self.byte_ss = -1 |
c4975078 | 111 | self.samplenum = None |
f39d2404 UH |
112 | self.bitcount = 0 |
113 | self.databyte = 0 | |
114 | self.wr = -1 | |
5dd9af5b | 115 | self.is_repeat_start = 0 |
2b716038 | 116 | self.state = 'FIND START' |
de038c47 | 117 | self.oldscl = self.oldsda = 1 |
d94ff143 | 118 | self.oldpins = [1, 1] |
8d2a9636 BV |
119 | self.pdu_start = None |
120 | self.pdu_bits = 0 | |
de038c47 | 121 | self.bits = [] |
8d2a9636 BV |
122 | |
123 | def metadata(self, key, value): | |
124 | if key == srd.SRD_CONF_SAMPLERATE: | |
125 | self.samplerate = value | |
f39d2404 | 126 | |
8915b346 | 127 | def start(self): |
c515eed7 | 128 | self.out_python = self.register(srd.OUTPUT_PYTHON) |
8d2a9636 | 129 | self.out_ann = self.register(srd.OUTPUT_ANN) |
be6733ca | 130 | self.out_binary = self.register(srd.OUTPUT_BINARY) |
8d2a9636 BV |
131 | self.out_bitrate = self.register(srd.OUTPUT_META, |
132 | meta=(int, 'Bitrate', 'Bitrate from Start bit to Stop bit')) | |
3643fc3f | 133 | |
d94ff143 | 134 | def putx(self, data): |
de038c47 | 135 | self.put(self.ss, self.es, self.out_ann, data) |
d94ff143 UH |
136 | |
137 | def putp(self, data): | |
de038c47 | 138 | self.put(self.ss, self.es, self.out_python, data) |
d94ff143 | 139 | |
a929afa6 | 140 | def putb(self, data): |
de038c47 | 141 | self.put(self.ss, self.es, self.out_binary, data) |
a929afa6 | 142 | |
7b86f0bc | 143 | def is_start_condition(self, scl, sda): |
eb7082c9 | 144 | # START condition (S): SDA = falling, SCL = high |
7b86f0bc UH |
145 | if (self.oldsda == 1 and sda == 0) and scl == 1: |
146 | return True | |
147 | return False | |
148 | ||
149 | def is_data_bit(self, scl, sda): | |
eb7082c9 | 150 | # Data sampling of receiver: SCL = rising |
7b86f0bc UH |
151 | if self.oldscl == 0 and scl == 1: |
152 | return True | |
153 | return False | |
154 | ||
155 | def is_stop_condition(self, scl, sda): | |
eb7082c9 | 156 | # STOP condition (P): SDA = rising, SCL = high |
7b86f0bc UH |
157 | if (self.oldsda == 0 and sda == 1) and scl == 1: |
158 | return True | |
159 | return False | |
160 | ||
e5080882 | 161 | def found_start(self, scl, sda): |
de038c47 | 162 | self.ss, self.es = self.samplenum, self.samplenum |
8d2a9636 BV |
163 | self.pdu_start = self.samplenum |
164 | self.pdu_bits = 0 | |
c4975078 | 165 | cmd = 'START REPEAT' if (self.is_repeat_start == 1) else 'START' |
d94ff143 UH |
166 | self.putp([cmd, None]) |
167 | self.putx([proto[cmd][0], proto[cmd][1:]]) | |
2b716038 | 168 | self.state = 'FIND ADDRESS' |
7b86f0bc | 169 | self.bitcount = self.databyte = 0 |
5dd9af5b | 170 | self.is_repeat_start = 1 |
7b86f0bc | 171 | self.wr = -1 |
de038c47 | 172 | self.bits = [] |
7b86f0bc | 173 | |
c4975078 | 174 | # Gather 8 bits of data plus the ACK/NACK bit. |
e5080882 | 175 | def found_address_or_data(self, scl, sda): |
7b86f0bc UH |
176 | # Address and data are transmitted MSB-first. |
177 | self.databyte <<= 1 | |
178 | self.databyte |= sda | |
179 | ||
de038c47 | 180 | # Remember the start of the first data/address bit. |
c4975078 | 181 | if self.bitcount == 0: |
de038c47 UH |
182 | self.byte_ss = self.samplenum |
183 | ||
184 | # Store individual bits and their start/end samplenumbers. | |
185 | # In the list, index 0 represents the LSB (I²C transmits MSB-first). | |
186 | self.bits.insert(0, [sda, self.samplenum, self.samplenum]) | |
187 | if self.bitcount > 0: | |
188 | self.bits[1][2] = self.samplenum | |
189 | if self.bitcount == 7: | |
190 | self.bitwidth = self.bits[1][2] - self.bits[2][2] | |
191 | self.bits[0][2] += self.bitwidth | |
c4975078 | 192 | |
7b86f0bc | 193 | # Return if we haven't collected all 8 + 1 bits, yet. |
de038c47 UH |
194 | if self.bitcount < 7: |
195 | self.bitcount += 1 | |
eb7082c9 | 196 | return |
7b86f0bc | 197 | |
d94ff143 | 198 | d = self.databyte |
2b716038 | 199 | if self.state == 'FIND ADDRESS': |
7b86f0bc | 200 | # The READ/WRITE bit is only in address bytes, not data bytes. |
bf1c3f4d | 201 | self.wr = 0 if (self.databyte & 1) else 1 |
d94ff143 UH |
202 | if self.options['address_format'] == 'shifted': |
203 | d = d >> 1 | |
15969949 | 204 | |
a929afa6 | 205 | bin_class = -1 |
2b716038 | 206 | if self.state == 'FIND ADDRESS' and self.wr == 1: |
a2d2aff2 | 207 | cmd = 'ADDRESS WRITE' |
a929afa6 | 208 | bin_class = 1 |
2b716038 | 209 | elif self.state == 'FIND ADDRESS' and self.wr == 0: |
a2d2aff2 | 210 | cmd = 'ADDRESS READ' |
a929afa6 | 211 | bin_class = 0 |
2b716038 | 212 | elif self.state == 'FIND DATA' and self.wr == 1: |
a2d2aff2 | 213 | cmd = 'DATA WRITE' |
a929afa6 | 214 | bin_class = 3 |
2b716038 | 215 | elif self.state == 'FIND DATA' and self.wr == 0: |
a2d2aff2 | 216 | cmd = 'DATA READ' |
a929afa6 | 217 | bin_class = 2 |
eb7082c9 | 218 | |
de038c47 UH |
219 | self.ss, self.es = self.byte_ss, self.samplenum + self.bitwidth |
220 | ||
221 | self.putp(['BITS', self.bits]) | |
d94ff143 | 222 | self.putp([cmd, d]) |
de038c47 | 223 | |
a929afa6 | 224 | self.putb((bin_class, bytes([d]))) |
7b86f0bc | 225 | |
de038c47 UH |
226 | for bit in self.bits: |
227 | self.put(bit[1], bit[2], self.out_ann, [5, ['%d' % bit[0]]]) | |
228 | ||
229 | if cmd.startswith('ADDRESS'): | |
230 | self.ss, self.es = self.samplenum, self.samplenum + self.bitwidth | |
231 | w = ['Write', 'Wr', 'W'] if self.wr else ['Read', 'Rd', 'R'] | |
232 | self.putx([proto[cmd][0], w]) | |
233 | self.ss, self.es = self.byte_ss, self.samplenum | |
234 | ||
235 | self.putx([proto[cmd][0], ['%s: %02X' % (proto[cmd][1], d), | |
236 | '%s: %02X' % (proto[cmd][2], d), '%02X' % d]]) | |
237 | ||
1b75abfd | 238 | # Done with this packet. |
1b75abfd | 239 | self.bitcount = self.databyte = 0 |
de038c47 | 240 | self.bits = [] |
2b716038 | 241 | self.state = 'FIND ACK' |
7b86f0bc | 242 | |
1b75abfd | 243 | def get_ack(self, scl, sda): |
de038c47 | 244 | self.ss, self.es = self.samplenum, self.samplenum + self.bitwidth |
d94ff143 UH |
245 | cmd = 'NACK' if (sda == 1) else 'ACK' |
246 | self.putp([cmd, None]) | |
247 | self.putx([proto[cmd][0], proto[cmd][1:]]) | |
1b75abfd BV |
248 | # There could be multiple data bytes in a row, so either find |
249 | # another data byte or a STOP condition next. | |
2b716038 | 250 | self.state = 'FIND DATA' |
7b86f0bc | 251 | |
e5080882 | 252 | def found_stop(self, scl, sda): |
8d2a9636 BV |
253 | # Meta bitrate |
254 | elapsed = 1 / float(self.samplerate) * (self.samplenum - self.pdu_start + 1) | |
255 | bitrate = int(1 / elapsed * self.pdu_bits) | |
de038c47 | 256 | self.put(self.byte_ss, self.samplenum, self.out_bitrate, bitrate) |
8d2a9636 | 257 | |
d94ff143 | 258 | cmd = 'STOP' |
de038c47 | 259 | self.ss, self.es = self.samplenum, self.samplenum |
d94ff143 UH |
260 | self.putp([cmd, None]) |
261 | self.putx([proto[cmd][0], proto[cmd][1:]]) | |
2b716038 | 262 | self.state = 'FIND START' |
5dd9af5b | 263 | self.is_repeat_start = 0 |
7b86f0bc | 264 | self.wr = -1 |
de038c47 | 265 | self.bits = [] |
7b86f0bc | 266 | |
2b9837d9 | 267 | def decode(self, ss, es, data): |
8d2a9636 BV |
268 | if self.samplerate is None: |
269 | raise Exception("Cannot decode without samplerate.") | |
2fcd7c22 UH |
270 | for (self.samplenum, pins) in data: |
271 | ||
272 | # Ignore identical samples early on (for performance reasons). | |
273 | if self.oldpins == pins: | |
274 | continue | |
275 | self.oldpins, (scl, sda) = pins, pins | |
f39d2404 | 276 | |
8d2a9636 BV |
277 | self.pdu_bits += 1 |
278 | ||
7b86f0bc | 279 | # State machine. |
2b716038 | 280 | if self.state == 'FIND START': |
7b86f0bc | 281 | if self.is_start_condition(scl, sda): |
e5080882 | 282 | self.found_start(scl, sda) |
2b716038 | 283 | elif self.state == 'FIND ADDRESS': |
7b86f0bc | 284 | if self.is_data_bit(scl, sda): |
e5080882 | 285 | self.found_address_or_data(scl, sda) |
2b716038 | 286 | elif self.state == 'FIND DATA': |
7b86f0bc | 287 | if self.is_data_bit(scl, sda): |
e5080882 | 288 | self.found_address_or_data(scl, sda) |
7b86f0bc | 289 | elif self.is_start_condition(scl, sda): |
e5080882 | 290 | self.found_start(scl, sda) |
7b86f0bc | 291 | elif self.is_stop_condition(scl, sda): |
e5080882 | 292 | self.found_stop(scl, sda) |
2b716038 | 293 | elif self.state == 'FIND ACK': |
1b75abfd BV |
294 | if self.is_data_bit(scl, sda): |
295 | self.get_ack(scl, sda) | |
7b86f0bc | 296 | else: |
0eeeb544 | 297 | raise Exception('Invalid state: %s' % self.state) |
f39d2404 UH |
298 | |
299 | # Save current SDA/SCL values for the next round. | |
de038c47 | 300 | self.oldscl, self.oldsda = scl, sda |
f39d2404 | 301 |