2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2017 Kevin Redon <kingkevin@cuvoodoo.info>
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.
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.
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/>.
20 import sigrokdecode as srd
22 class SamplerateError(Exception):
25 # Timing values in us for the signal at regular and overdrive speed.
91 class Decoder(srd.Decoder):
94 name = '1-Wire link layer'
95 longname = '1-Wire serial communication bus (link layer)'
96 desc = 'Bidirectional, half-duplex, asynchronous serial bus.'
99 outputs = ['onewire_link']
101 {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire signal line'},
104 {'id': 'overdrive', 'desc': 'Start in overdrive speed',
105 'default': 'no', 'values': ('yes', 'no')},
109 ('warnings', 'Warnings'),
111 ('presence', 'Presence'),
112 ('overdrive', 'Overdrive speed notifications'),
115 ('bits', 'Bits', (0, 2, 3)),
116 ('info', 'Info', (4,)),
117 ('warnings', 'Warnings', (1,)),
121 self.samplerate = None
123 self.state = 'INITIAL'
128 self.overdrive = False
133 self.out_python = self.register(srd.OUTPUT_PYTHON)
134 self.out_ann = self.register(srd.OUTPUT_ANN)
135 self.overdrive = (self.options['overdrive'] == 'yes')
141 # Check if samplerate is appropriate.
142 if self.options['overdrive'] == 'yes':
143 if self.samplerate < 2000000:
144 self.putm([1, ['Sampling rate is too low. Must be above ' +
145 '2MHz for proper overdrive mode decoding.']])
146 elif self.samplerate < 5000000:
147 self.putm([1, ['Sampling rate is suggested to be above 5MHz ' +
148 'for proper overdrive mode decoding.']])
150 if self.samplerate < 400000:
151 self.putm([1, ['Sampling rate is too low. Must be above ' +
152 '400kHz for proper normal mode decoding.']])
153 elif self.samplerate < 1000000:
154 self.putm([1, ['Sampling rate is suggested to be above ' +
155 '1MHz for proper normal mode decoding.']])
157 def metadata(self, key, value):
158 if key != srd.SRD_CONF_SAMPLERATE:
160 self.samplerate = value
162 def decode(self, ss, es, data):
163 if not self.samplerate:
164 raise SamplerateError('Cannot decode without samplerate.')
165 for (self.samplenum, (owr,)) in data:
166 if self.samplenum == 0:
170 if self.state == 'INITIAL': # Unknown initial state.
171 # Wait until we reach the idle high state.
174 self.rise = self.samplenum
176 elif self.state == 'IDLE': # Idle high state.
177 # Wait for falling edge.
180 self.fall = self.samplenum
181 # Get time since last rising edge.
182 time = ((self.fall - self.rise) / self.samplerate) * 1000000.0
183 if self.rise > 0 and \
184 time < timing['REC']['min'][self.overdrive]:
185 self.put(self.fall, self.rise, self.out_ann,
186 [1, ['Recovery time not long enough'
187 'Recovery too short',
188 'REC < ' + str(timing['REC']['min'][self.overdrive])]])
189 # A reset pulse or slot can start on a falling edge.
191 # TODO: Check minimum recovery time.
192 elif self.state == 'LOW': # Reset pulse or slot.
193 # Wait for rising edge.
196 self.rise = self.samplenum
197 # Detect reset or slot base on timing.
198 time = ((self.rise - self.fall) / self.samplerate) * 1000000.0
199 if time >= timing['RSTL']['min'][False]: # Normal reset pulse.
200 if time > timing['RSTL']['max'][False]:
201 self.put(self.fall, self.rise, self.out_ann,
202 [1, ['Too long reset pulse might mask interrupt ' +
203 'signalling by other devices',
204 'Reset pulse too long',
205 'RST > ' + str(timing['RSTL']['max'][False])]])
206 # Regular reset pulse clears overdrive speed.
208 self.put(self.fall, self.rise, self.out_ann,
209 [4, ['Exiting overdrive mode', 'Overdrive off']])
210 self.overdrive = False
211 self.put(self.fall, self.rise, self.out_ann,
212 [2, ['Reset', 'Rst', 'R']])
213 self.state = 'PRESENCE DETECT HIGH'
214 elif self.overdrive == True and \
215 time >= timing['RSTL']['min'][self.overdrive] and \
216 time < timing['RSTL']['max'][self.overdrive]:
217 # Overdrive reset pulse.
218 self.put(self.fall, self.rise, self.out_ann,
219 [2, ['Reset', 'Rst', 'R']])
220 self.state = 'PRESENCE DETECT HIGH'
221 elif time < timing['SLOT']['max'][self.overdrive]:
222 # Read/write time slot.
223 if time < timing['LOWR']['min'][self.overdrive]:
224 self.put(self.fall, self.rise, self.out_ann,
225 [1, ['Low signal not long enough',
227 'LOW < ' + str(timing['LOWR']['min'][self.overdrive])]])
228 if time < timing['LOWR']['max'][self.overdrive]:
229 self.bit = 1 # Short pulse is a 1 bit.
231 self.bit = 0 # Long pulse is a 0 bit.
232 # Wait for end of slot.
235 # Timing outside of known states.
236 self.put(self.fall, self.rise, self.out_ann,
237 [1, ['Erroneous signal', 'Error', 'Err', 'E']])
239 elif self.state == 'PRESENCE DETECT HIGH': # Wait for slave presence signal.
240 # Calculate time since rising edge.
241 time = ((self.samplenum - self.rise) / self.samplerate) * 1000000.0
242 if owr != 0 and time < timing['PDH']['max'][self.overdrive]:
244 elif owr == 0: # Presence detected.
245 if time < timing['PDH']['min'][self.overdrive]:
246 self.put(self.rise, self.samplenum, self.out_ann,
247 [1, ['Presence detect signal is too early',
248 'Presence detect too early',
249 'PDH < ' + str(timing['PDH']['min'][self.overdrive])]])
250 self.fall = self.samplenum
251 self.state = 'PRESENCE DETECT LOW'
252 else: # No presence detected.
253 self.put(self.rise, self.samplenum, self.out_ann,
254 [3, ['Presence: false', 'Presence', 'Pres', 'P']])
255 self.put(self.rise, self.samplenum, self.out_python,
256 ['RESET/PRESENCE', False])
258 elif self.state == 'PRESENCE DETECT LOW': # Slave presence signalled.
259 # Wait for end of presence signal (on rising edge).
262 # Calculate time since start of presence signal.
263 time = ((self.samplenum - self.fall) / self.samplerate) * 1000000.0
264 if time < timing['PDL']['min'][self.overdrive]:
265 self.put(self.fall, self.samplenum, self.out_ann,
266 [1, ['Presence detect signal is too short',
267 'Presence detect too short',
268 'PDL < ' + str(timing['PDL']['min'][self.overdrive])]])
269 elif time > timing['PDL']['max'][self.overdrive]:
270 self.put(self.fall, self.samplenum, self.out_ann,
271 [1, ['Presence detect signal is too long',
272 'Presence detect too long',
273 'PDL > ' + str(timing['PDL']['max'][self.overdrive])]])
274 if time > timing['RSTH']['min'][self.overdrive]:
275 self.rise = self.samplenum
276 # Wait for end of presence detect.
277 self.state = 'PRESENCE DETECT'
279 # End states (for additional checks).
280 if self.state == 'SLOT': # Wait for end of time slot.
281 # Calculate time since falling edge.
282 time = ((self.samplenum - self.fall) / self.samplerate) * 1000000.0
283 if owr != 0 and time < timing['SLOT']['min'][self.overdrive]:
285 elif owr == 0: # Low detected before end of slot.
286 # Warn about irregularity.
287 self.put(self.fall, self.samplenum, self.out_ann,
288 [1, ['Time slot not long enough',
290 'SLOT < ' + str(timing['SLOT']['min'][self.overdrive])]])
291 # Don't output invalid bit.
292 self.fall = self.samplenum
294 else: # End of time slot.
296 self.put(self.fall, self.samplenum, self.out_ann,
297 [0, ['Bit: %d' % self.bit, '%d' % self.bit]])
298 self.put(self.fall, self.samplenum, self.out_python,
301 if self.bit_count >= 0:
302 self.command += (self.bit << self.bit_count)
304 # Check for overdrive ROM command.
305 if self.bit_count >= 8:
306 if self.command == 0x3c or self.command == 0x69:
307 self.overdrive = True
308 self.put(self.samplenum, self.samplenum,
310 [4, ['Entering overdrive mode', 'Overdrive on']])
314 if self.state == 'PRESENCE DETECT':
315 # Wait for end of presence detect.
316 # Calculate time since falling edge.
317 time = ((self.samplenum - self.rise) / self.samplerate) * 1000000.0
318 if owr != 0 and time < timing['RSTH']['min'][self.overdrive]:
320 elif owr == 0: # Low detected before end of presence detect.
321 # Warn about irregularity.
322 self.put(self.fall, self.samplenum, self.out_ann,
323 [1, ['Presence detect not long enough',
324 'Presence detect too short',
325 'RTSH < ' + str(timing['RSTH']['min'][self.overdrive])]])
326 # Inform about presence detected.
327 self.put(self.rise, self.samplenum, self.out_ann,
328 [3, ['Slave presence detected', 'Slave present',
330 self.put(self.rise, self.samplenum, self.out_python,
331 ['RESET/PRESENCE', True])
332 self.fall = self.samplenum
334 else: # End of time slot.
335 # Inform about presence detected.
336 self.put(self.rise, self.samplenum, self.out_ann,
337 [3, ['Presence: true', 'Presence', 'Pres', 'P']])
338 self.put(self.rise, self.samplenum, self.out_python,
339 ['RESET/PRESENCE', True])
340 self.rise = self.samplenum
341 # Start counting the first 8 bits to get the ROM command.