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1 | ## | |
2 | ## This file is part of the libsigrokdecode project. | |
3 | ## | |
4 | ## Copyright (C) 2017 Kevin Redon <kingkevin@cuvoodoo.info> | |
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, see <http://www.gnu.org/licenses/>. | |
18 | ## | |
19 | ||
20 | import sigrokdecode as srd | |
21 | ||
22 | class SamplerateError(Exception): | |
23 | pass | |
24 | ||
25 | # Timing values in us for the signal at regular and overdrive speed. | |
26 | timing = { | |
27 | 'RSTL': { | |
28 | 'min': { | |
29 | False: 480.0, | |
30 | True: 48.0, | |
31 | }, | |
32 | 'max': { | |
33 | False: 960.0, | |
34 | True: 80.0, | |
35 | }, | |
36 | }, | |
37 | 'RSTH': { | |
38 | 'min': { | |
39 | False: 480.0, | |
40 | True: 48.0, | |
41 | }, | |
42 | }, | |
43 | 'PDH': { | |
44 | 'min': { | |
45 | False: 15.0, | |
46 | True: 2.0, | |
47 | }, | |
48 | 'max': { | |
49 | False: 60.0, | |
50 | True: 6.0, | |
51 | }, | |
52 | }, | |
53 | 'PDL': { | |
54 | 'min': { | |
55 | False: 60.0, | |
56 | True: 8.0, | |
57 | }, | |
58 | 'max': { | |
59 | False: 240.0, | |
60 | True: 24.0, | |
61 | }, | |
62 | }, | |
63 | 'SLOT': { | |
64 | 'min': { | |
65 | False: 60.0, | |
66 | True: 6.0, | |
67 | }, | |
68 | 'max': { | |
69 | False: 120.0, | |
70 | True: 16.0, | |
71 | }, | |
72 | }, | |
73 | 'REC': { | |
74 | 'min': { | |
75 | False: 1.0, | |
76 | True: 1.0, | |
77 | }, | |
78 | }, | |
79 | 'LOWR': { | |
80 | 'min': { | |
81 | False: 1.0, | |
82 | True: 1.0, | |
83 | }, | |
84 | 'max': { | |
85 | False: 15.0, | |
86 | True: 2.0, | |
87 | }, | |
88 | }, | |
89 | } | |
90 | ||
91 | class Decoder(srd.Decoder): | |
92 | api_version = 3 | |
93 | id = 'onewire_link' | |
94 | name = '1-Wire link layer' | |
95 | longname = '1-Wire serial communication bus (link layer)' | |
96 | desc = 'Bidirectional, half-duplex, asynchronous serial bus.' | |
97 | license = 'gplv2+' | |
98 | inputs = ['logic'] | |
99 | outputs = ['onewire_link'] | |
100 | tags = ['Embedded/industrial'] | |
101 | channels = ( | |
102 | {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire signal line'}, | |
103 | ) | |
104 | options = ( | |
105 | {'id': 'overdrive', 'desc': 'Start in overdrive speed', | |
106 | 'default': 'no', 'values': ('yes', 'no')}, | |
107 | ) | |
108 | annotations = ( | |
109 | ('bit', 'Bit'), | |
110 | ('warning', 'Warning'), | |
111 | ('reset', 'Reset'), | |
112 | ('presence', 'Presence'), | |
113 | ('overdrive', 'Overdrive speed notification'), | |
114 | ) | |
115 | annotation_rows = ( | |
116 | ('bits', 'Bits', (0, 2, 3)), | |
117 | ('info', 'Info', (4,)), | |
118 | ('warnings', 'Warnings', (1,)), | |
119 | ) | |
120 | ||
121 | def __init__(self): | |
122 | self.reset() | |
123 | ||
124 | def reset(self): | |
125 | self.samplerate = None | |
126 | self.state = 'INITIAL' | |
127 | self.present = 0 | |
128 | self.bit = 0 | |
129 | self.bit_count = -1 | |
130 | self.command = 0 | |
131 | self.overdrive = False | |
132 | self.fall = 0 | |
133 | self.rise = 0 | |
134 | ||
135 | def start(self): | |
136 | self.out_python = self.register(srd.OUTPUT_PYTHON) | |
137 | self.out_ann = self.register(srd.OUTPUT_ANN) | |
138 | self.overdrive = (self.options['overdrive'] == 'yes') | |
139 | self.fall = 0 | |
140 | self.rise = 0 | |
141 | self.bit_count = -1 | |
142 | ||
143 | def putm(self, data): | |
144 | self.put(0, 0, self.out_ann, data) | |
145 | ||
146 | def putpfs(self, data): | |
147 | self.put(self.fall, self.samplenum, self.out_python, data) | |
148 | ||
149 | def putfs(self, data): | |
150 | self.put(self.fall, self.samplenum, self.out_ann, data) | |
151 | ||
152 | def putfr(self, data): | |
153 | self.put(self.fall, self.rise, self.out_ann, data) | |
154 | ||
155 | def putprs(self, data): | |
156 | self.put(self.rise, self.samplenum, self.out_python, data) | |
157 | ||
158 | def putrs(self, data): | |
159 | self.put(self.rise, self.samplenum, self.out_ann, data) | |
160 | ||
161 | def checks(self): | |
162 | # Check if samplerate is appropriate. | |
163 | if self.options['overdrive'] == 'yes': | |
164 | if self.samplerate < 2000000: | |
165 | self.putm([1, ['Sampling rate is too low. Must be above ' + | |
166 | '2MHz for proper overdrive mode decoding.']]) | |
167 | elif self.samplerate < 5000000: | |
168 | self.putm([1, ['Sampling rate is suggested to be above 5MHz ' + | |
169 | 'for proper overdrive mode decoding.']]) | |
170 | else: | |
171 | if self.samplerate < 400000: | |
172 | self.putm([1, ['Sampling rate is too low. Must be above ' + | |
173 | '400kHz for proper normal mode decoding.']]) | |
174 | elif self.samplerate < 1000000: | |
175 | self.putm([1, ['Sampling rate is suggested to be above ' + | |
176 | '1MHz for proper normal mode decoding.']]) | |
177 | ||
178 | def metadata(self, key, value): | |
179 | if key != srd.SRD_CONF_SAMPLERATE: | |
180 | return | |
181 | self.samplerate = value | |
182 | ||
183 | def wait_falling_timeout(self, start, t): | |
184 | # Wait until either a falling edge is seen, and/or the specified | |
185 | # number of samples have been skipped (i.e. time has passed). | |
186 | cnt = int((t[self.overdrive] / 1000000.0) * self.samplerate) | |
187 | samples_to_skip = (start + cnt) - self.samplenum | |
188 | samples_to_skip = samples_to_skip if (samples_to_skip > 0) else 0 | |
189 | return self.wait([{0: 'f'}, {'skip': samples_to_skip}]) | |
190 | ||
191 | def decode(self): | |
192 | if not self.samplerate: | |
193 | raise SamplerateError('Cannot decode without samplerate.') | |
194 | self.checks() | |
195 | while True: | |
196 | # State machine. | |
197 | if self.state == 'INITIAL': # Unknown initial state. | |
198 | # Wait until we reach the idle high state. | |
199 | self.wait({0: 'h'}) | |
200 | self.rise = self.samplenum | |
201 | self.state = 'IDLE' | |
202 | elif self.state == 'IDLE': # Idle high state. | |
203 | # Wait for falling edge. | |
204 | self.wait({0: 'f'}) | |
205 | self.fall = self.samplenum | |
206 | # Get time since last rising edge. | |
207 | time = ((self.fall - self.rise) / self.samplerate) * 1000000.0 | |
208 | if self.rise > 0 and \ | |
209 | time < timing['REC']['min'][self.overdrive]: | |
210 | self.putfr([1, ['Recovery time not long enough' | |
211 | 'Recovery too short', | |
212 | 'REC < ' + str(timing['REC']['min'][self.overdrive])]]) | |
213 | # A reset pulse or slot can start on a falling edge. | |
214 | self.state = 'LOW' | |
215 | # TODO: Check minimum recovery time. | |
216 | elif self.state == 'LOW': # Reset pulse or slot. | |
217 | # Wait for rising edge. | |
218 | self.wait({0: 'r'}) | |
219 | self.rise = self.samplenum | |
220 | # Detect reset or slot base on timing. | |
221 | time = ((self.rise - self.fall) / self.samplerate) * 1000000.0 | |
222 | if time >= timing['RSTL']['min'][False]: # Normal reset pulse. | |
223 | if time > timing['RSTL']['max'][False]: | |
224 | self.putfr([1, ['Too long reset pulse might mask interrupt ' + | |
225 | 'signalling by other devices', | |
226 | 'Reset pulse too long', | |
227 | 'RST > ' + str(timing['RSTL']['max'][False])]]) | |
228 | # Regular reset pulse clears overdrive speed. | |
229 | if self.overdrive: | |
230 | self.putfr([4, ['Exiting overdrive mode', 'Overdrive off']]) | |
231 | self.overdrive = False | |
232 | self.putfr([2, ['Reset', 'Rst', 'R']]) | |
233 | self.state = 'PRESENCE DETECT HIGH' | |
234 | elif self.overdrive == True and \ | |
235 | time >= timing['RSTL']['min'][self.overdrive] and \ | |
236 | time < timing['RSTL']['max'][self.overdrive]: | |
237 | # Overdrive reset pulse. | |
238 | self.putfr([2, ['Reset', 'Rst', 'R']]) | |
239 | self.state = 'PRESENCE DETECT HIGH' | |
240 | elif time < timing['SLOT']['max'][self.overdrive]: | |
241 | # Read/write time slot. | |
242 | if time < timing['LOWR']['min'][self.overdrive]: | |
243 | self.putfr([1, ['Low signal not long enough', | |
244 | 'Low too short', | |
245 | 'LOW < ' + str(timing['LOWR']['min'][self.overdrive])]]) | |
246 | if time < timing['LOWR']['max'][self.overdrive]: | |
247 | self.bit = 1 # Short pulse is a 1 bit. | |
248 | else: | |
249 | self.bit = 0 # Long pulse is a 0 bit. | |
250 | # Wait for end of slot. | |
251 | self.state = 'SLOT' | |
252 | else: | |
253 | # Timing outside of known states. | |
254 | self.putfr([1, ['Erroneous signal', 'Error', 'Err', 'E']]) | |
255 | self.state = 'IDLE' | |
256 | elif self.state == 'PRESENCE DETECT HIGH': # Wait for slave presence signal. | |
257 | # Wait for a falling edge and/or presence detect signal. | |
258 | self.wait_falling_timeout(self.rise, timing['PDH']['max']) | |
259 | ||
260 | # Calculate time since rising edge. | |
261 | time = ((self.samplenum - self.rise) / self.samplerate) * 1000000.0 | |
262 | ||
263 | if self.matched[0] and not self.matched[1]: | |
264 | # Presence detected. | |
265 | if time < timing['PDH']['min'][self.overdrive]: | |
266 | self.putrs([1, ['Presence detect signal is too early', | |
267 | 'Presence detect too early', | |
268 | 'PDH < ' + str(timing['PDH']['min'][self.overdrive])]]) | |
269 | self.fall = self.samplenum | |
270 | self.state = 'PRESENCE DETECT LOW' | |
271 | else: # No presence detected. | |
272 | self.putrs([3, ['Presence: false', 'Presence', 'Pres', 'P']]) | |
273 | self.putprs(['RESET/PRESENCE', False]) | |
274 | self.state = 'IDLE' | |
275 | elif self.state == 'PRESENCE DETECT LOW': # Slave presence signalled. | |
276 | # Wait for end of presence signal (on rising edge). | |
277 | self.wait({0: 'r'}) | |
278 | # Calculate time since start of presence signal. | |
279 | time = ((self.samplenum - self.fall) / self.samplerate) * 1000000.0 | |
280 | if time < timing['PDL']['min'][self.overdrive]: | |
281 | self.putfs([1, ['Presence detect signal is too short', | |
282 | 'Presence detect too short', | |
283 | 'PDL < ' + str(timing['PDL']['min'][self.overdrive])]]) | |
284 | elif time > timing['PDL']['max'][self.overdrive]: | |
285 | self.putfs([1, ['Presence detect signal is too long', | |
286 | 'Presence detect too long', | |
287 | 'PDL > ' + str(timing['PDL']['max'][self.overdrive])]]) | |
288 | if time > timing['RSTH']['min'][self.overdrive]: | |
289 | self.rise = self.samplenum | |
290 | # Wait for end of presence detect. | |
291 | self.state = 'PRESENCE DETECT' | |
292 | ||
293 | # End states (for additional checks). | |
294 | if self.state == 'SLOT': # Wait for end of time slot. | |
295 | # Wait for a falling edge and/or end of timeslot. | |
296 | self.wait_falling_timeout(self.fall, timing['SLOT']['min']) | |
297 | ||
298 | if self.matched[0] and not self.matched[1]: | |
299 | # Low detected before end of slot. | |
300 | self.putfs([1, ['Time slot not long enough', | |
301 | 'Slot too short', | |
302 | 'SLOT < ' + str(timing['SLOT']['min'][self.overdrive])]]) | |
303 | # Don't output invalid bit. | |
304 | self.fall = self.samplenum | |
305 | self.state = 'LOW' | |
306 | else: # End of time slot. | |
307 | # Output bit. | |
308 | self.putfs([0, ['Bit: %d' % self.bit, '%d' % self.bit]]) | |
309 | self.putpfs(['BIT', self.bit]) | |
310 | # Save command bits. | |
311 | if self.bit_count >= 0: | |
312 | self.command += (self.bit << self.bit_count) | |
313 | self.bit_count += 1 | |
314 | # Check for overdrive ROM command. | |
315 | if self.bit_count >= 8: | |
316 | if self.command == 0x3c or self.command == 0x69: | |
317 | self.overdrive = True | |
318 | self.put(self.samplenum, self.samplenum, | |
319 | self.out_ann, | |
320 | [4, ['Entering overdrive mode', 'Overdrive on']]) | |
321 | self.bit_count = -1 | |
322 | self.state = 'IDLE' | |
323 | ||
324 | if self.state == 'PRESENCE DETECT': | |
325 | # Wait for a falling edge and/or end of presence detect. | |
326 | self.wait_falling_timeout(self.rise, timing['RSTH']['min']) | |
327 | ||
328 | if self.matched[0] and not self.matched[1]: | |
329 | # Low detected before end of presence detect. | |
330 | self.putfs([1, ['Presence detect not long enough', | |
331 | 'Presence detect too short', | |
332 | 'RTSH < ' + str(timing['RSTH']['min'][self.overdrive])]]) | |
333 | # Inform about presence detected. | |
334 | self.putrs([3, ['Slave presence detected', 'Slave present', | |
335 | 'Present', 'P']]) | |
336 | self.putprs(['RESET/PRESENCE', True]) | |
337 | self.fall = self.samplenum | |
338 | self.state = 'LOW' | |
339 | else: # End of time slot. | |
340 | # Inform about presence detected. | |
341 | self.putrs([3, ['Presence: true', 'Presence', 'Pres', 'P']]) | |
342 | self.putprs(['RESET/PRESENCE', True]) | |
343 | self.rise = self.samplenum | |
344 | # Start counting the first 8 bits to get the ROM command. | |
345 | self.bit_count = 0 | |
346 | self.command = 0 | |
347 | self.state = 'IDLE' |