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
122 self.state = 'INITIAL'
127 self.overdrive = False
132 self.out_python = self.register(srd.OUTPUT_PYTHON)
133 self.out_ann = self.register(srd.OUTPUT_ANN)
134 self.overdrive = (self.options['overdrive'] == 'yes')
139 def putm(self, data):
140 self.put(0, 0, self.out_ann, data)
142 def putpfs(self, data):
143 self.put(self.fall, self.samplenum, self.out_python, data)
145 def putfs(self, data):
146 self.put(self.fall, self.samplenum, self.out_ann, data)
148 def putfr(self, data):
149 self.put(self.fall, self.rise, self.out_ann, data)
151 def putprs(self, data):
152 self.put(self.rise, self.samplenum, self.out_python, data)
154 def putrs(self, data):
155 self.put(self.rise, self.samplenum, self.out_ann, data)
158 # Check if samplerate is appropriate.
159 if self.options['overdrive'] == 'yes':
160 if self.samplerate < 2000000:
161 self.putm([1, ['Sampling rate is too low. Must be above ' +
162 '2MHz for proper overdrive mode decoding.']])
163 elif self.samplerate < 5000000:
164 self.putm([1, ['Sampling rate is suggested to be above 5MHz ' +
165 'for proper overdrive mode decoding.']])
167 if self.samplerate < 400000:
168 self.putm([1, ['Sampling rate is too low. Must be above ' +
169 '400kHz for proper normal mode decoding.']])
170 elif self.samplerate < 1000000:
171 self.putm([1, ['Sampling rate is suggested to be above ' +
172 '1MHz for proper normal mode decoding.']])
174 def metadata(self, key, value):
175 if key != srd.SRD_CONF_SAMPLERATE:
177 self.samplerate = value
179 def wait_falling_timeout(self, start, t):
180 # Wait until either a falling edge is seen, and/or the specified
181 # number of samples have been skipped (i.e. time has passed).
182 cnt = int((t[self.overdrive] / 1000000.0) * self.samplerate)
183 samples_to_skip = (start + cnt) - self.samplenum
184 samples_to_skip = samples_to_skip if (samples_to_skip > 0) else 0
185 return self.wait([{0: 'f'}, {'skip': samples_to_skip}])
188 if not self.samplerate:
189 raise SamplerateError('Cannot decode without samplerate.')
193 if self.state == 'INITIAL': # Unknown initial state.
194 # Wait until we reach the idle high state.
196 self.rise = self.samplenum
198 elif self.state == 'IDLE': # Idle high state.
199 # Wait for falling edge.
201 self.fall = self.samplenum
202 # Get time since last rising edge.
203 time = ((self.fall - self.rise) / self.samplerate) * 1000000.0
204 if self.rise > 0 and \
205 time < timing['REC']['min'][self.overdrive]:
206 self.putfr([1, ['Recovery time not long enough'
207 'Recovery too short',
208 'REC < ' + str(timing['REC']['min'][self.overdrive])]])
209 # A reset pulse or slot can start on a falling edge.
211 # TODO: Check minimum recovery time.
212 elif self.state == 'LOW': # Reset pulse or slot.
213 # Wait for rising edge.
215 self.rise = self.samplenum
216 # Detect reset or slot base on timing.
217 time = ((self.rise - self.fall) / self.samplerate) * 1000000.0
218 if time >= timing['RSTL']['min'][False]: # Normal reset pulse.
219 if time > timing['RSTL']['max'][False]:
220 self.putfr([1, ['Too long reset pulse might mask interrupt ' +
221 'signalling by other devices',
222 'Reset pulse too long',
223 'RST > ' + str(timing['RSTL']['max'][False])]])
224 # Regular reset pulse clears overdrive speed.
226 self.putfr([4, ['Exiting overdrive mode', 'Overdrive off']])
227 self.overdrive = False
228 self.putfr([2, ['Reset', 'Rst', 'R']])
229 self.state = 'PRESENCE DETECT HIGH'
230 elif self.overdrive == True and \
231 time >= timing['RSTL']['min'][self.overdrive] and \
232 time < timing['RSTL']['max'][self.overdrive]:
233 # Overdrive reset pulse.
234 self.putfr([2, ['Reset', 'Rst', 'R']])
235 self.state = 'PRESENCE DETECT HIGH'
236 elif time < timing['SLOT']['max'][self.overdrive]:
237 # Read/write time slot.
238 if time < timing['LOWR']['min'][self.overdrive]:
239 self.putfr([1, ['Low signal not long enough',
241 'LOW < ' + str(timing['LOWR']['min'][self.overdrive])]])
242 if time < timing['LOWR']['max'][self.overdrive]:
243 self.bit = 1 # Short pulse is a 1 bit.
245 self.bit = 0 # Long pulse is a 0 bit.
246 # Wait for end of slot.
249 # Timing outside of known states.
250 self.putfr([1, ['Erroneous signal', 'Error', 'Err', 'E']])
252 elif self.state == 'PRESENCE DETECT HIGH': # Wait for slave presence signal.
253 # Wait for a falling edge and/or presence detect signal.
254 self.wait_falling_timeout(self.rise, timing['PDH']['max'])
256 # Calculate time since rising edge.
257 time = ((self.samplenum - self.rise) / self.samplerate) * 1000000.0
259 if self.matched[0] and not self.matched[1]:
261 if time < timing['PDH']['min'][self.overdrive]:
262 self.putrs([1, ['Presence detect signal is too early',
263 'Presence detect too early',
264 'PDH < ' + str(timing['PDH']['min'][self.overdrive])]])
265 self.fall = self.samplenum
266 self.state = 'PRESENCE DETECT LOW'
267 else: # No presence detected.
268 self.putrs([3, ['Presence: false', 'Presence', 'Pres', 'P']])
269 self.putprs(['RESET/PRESENCE', False])
271 elif self.state == 'PRESENCE DETECT LOW': # Slave presence signalled.
272 # Wait for end of presence signal (on rising edge).
274 # Calculate time since start of presence signal.
275 time = ((self.samplenum - self.fall) / self.samplerate) * 1000000.0
276 if time < timing['PDL']['min'][self.overdrive]:
277 self.putfs([1, ['Presence detect signal is too short',
278 'Presence detect too short',
279 'PDL < ' + str(timing['PDL']['min'][self.overdrive])]])
280 elif time > timing['PDL']['max'][self.overdrive]:
281 self.putfs([1, ['Presence detect signal is too long',
282 'Presence detect too long',
283 'PDL > ' + str(timing['PDL']['max'][self.overdrive])]])
284 if time > timing['RSTH']['min'][self.overdrive]:
285 self.rise = self.samplenum
286 # Wait for end of presence detect.
287 self.state = 'PRESENCE DETECT'
289 # End states (for additional checks).
290 if self.state == 'SLOT': # Wait for end of time slot.
291 # Wait for a falling edge and/or end of timeslot.
292 self.wait_falling_timeout(self.fall, timing['SLOT']['min'])
294 if self.matched[0] and not self.matched[1]:
295 # Low detected before end of slot.
296 self.putfs([1, ['Time slot not long enough',
298 'SLOT < ' + str(timing['SLOT']['min'][self.overdrive])]])
299 # Don't output invalid bit.
300 self.fall = self.samplenum
302 else: # End of time slot.
304 self.putfs([0, ['Bit: %d' % self.bit, '%d' % self.bit]])
305 self.putpfs(['BIT', self.bit])
307 if self.bit_count >= 0:
308 self.command += (self.bit << self.bit_count)
310 # Check for overdrive ROM command.
311 if self.bit_count >= 8:
312 if self.command == 0x3c or self.command == 0x69:
313 self.overdrive = True
314 self.put(self.samplenum, self.samplenum,
316 [4, ['Entering overdrive mode', 'Overdrive on']])
320 if self.state == 'PRESENCE DETECT':
321 # Wait for a falling edge and/or end of presence detect.
322 self.wait_falling_timeout(self.rise, timing['RSTH']['min'])
324 if self.matched[0] and not self.matched[1]:
325 # Low detected before end of presence detect.
326 self.putfs([1, ['Presence detect not long enough',
327 'Presence detect too short',
328 'RTSH < ' + str(timing['RSTH']['min'][self.overdrive])]])
329 # Inform about presence detected.
330 self.putrs([3, ['Slave presence detected', 'Slave present',
332 self.putprs(['RESET/PRESENCE', True])
333 self.fall = self.samplenum
335 else: # End of time slot.
336 # Inform about presence detected.
337 self.putrs([3, ['Presence: true', 'Presence', 'Pres', 'P']])
338 self.putprs(['RESET/PRESENCE', True])
339 self.rise = self.samplenum
340 # Start counting the first 8 bits to get the ROM command.