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,)),
124 self.samplerate = None
125 self.state = 'INITIAL'
130 self.overdrive = False
135 self.out_python = self.register(srd.OUTPUT_PYTHON)
136 self.out_ann = self.register(srd.OUTPUT_ANN)
137 self.overdrive = (self.options['overdrive'] == 'yes')
142 def putm(self, data):
143 self.put(0, 0, self.out_ann, data)
145 def putpfs(self, data):
146 self.put(self.fall, self.samplenum, self.out_python, data)
148 def putfs(self, data):
149 self.put(self.fall, self.samplenum, self.out_ann, data)
151 def putfr(self, data):
152 self.put(self.fall, self.rise, self.out_ann, data)
154 def putprs(self, data):
155 self.put(self.rise, self.samplenum, self.out_python, data)
157 def putrs(self, data):
158 self.put(self.rise, self.samplenum, self.out_ann, data)
161 # Check if samplerate is appropriate.
162 if self.options['overdrive'] == 'yes':
163 if self.samplerate < 2000000:
164 self.putm([1, ['Sampling rate is too low. Must be above ' +
165 '2MHz for proper overdrive mode decoding.']])
166 elif self.samplerate < 5000000:
167 self.putm([1, ['Sampling rate is suggested to be above 5MHz ' +
168 'for proper overdrive mode decoding.']])
170 if self.samplerate < 400000:
171 self.putm([1, ['Sampling rate is too low. Must be above ' +
172 '400kHz for proper normal mode decoding.']])
173 elif self.samplerate < 1000000:
174 self.putm([1, ['Sampling rate is suggested to be above ' +
175 '1MHz for proper normal mode decoding.']])
177 def metadata(self, key, value):
178 if key != srd.SRD_CONF_SAMPLERATE:
180 self.samplerate = value
182 def wait_falling_timeout(self, start, t):
183 # Wait until either a falling edge is seen, and/or the specified
184 # number of samples have been skipped (i.e. time has passed).
185 cnt = int((t[self.overdrive] / 1000000.0) * self.samplerate)
186 samples_to_skip = (start + cnt) - self.samplenum
187 samples_to_skip = samples_to_skip if (samples_to_skip > 0) else 0
188 return self.wait([{0: 'f'}, {'skip': samples_to_skip}])
191 if not self.samplerate:
192 raise SamplerateError('Cannot decode without samplerate.')
196 if self.state == 'INITIAL': # Unknown initial state.
197 # Wait until we reach the idle high state.
199 self.rise = self.samplenum
201 elif self.state == 'IDLE': # Idle high state.
202 # Wait for falling edge.
204 self.fall = self.samplenum
205 # Get time since last rising edge.
206 time = ((self.fall - self.rise) / self.samplerate) * 1000000.0
207 if self.rise > 0 and \
208 time < timing['REC']['min'][self.overdrive]:
209 self.putfr([1, ['Recovery time not long enough'
210 'Recovery too short',
211 'REC < ' + str(timing['REC']['min'][self.overdrive])]])
212 # A reset pulse or slot can start on a falling edge.
214 # TODO: Check minimum recovery time.
215 elif self.state == 'LOW': # Reset pulse or slot.
216 # Wait for rising edge.
218 self.rise = self.samplenum
219 # Detect reset or slot base on timing.
220 time = ((self.rise - self.fall) / self.samplerate) * 1000000.0
221 if time >= timing['RSTL']['min'][False]: # Normal reset pulse.
222 if time > timing['RSTL']['max'][False]:
223 self.putfr([1, ['Too long reset pulse might mask interrupt ' +
224 'signalling by other devices',
225 'Reset pulse too long',
226 'RST > ' + str(timing['RSTL']['max'][False])]])
227 # Regular reset pulse clears overdrive speed.
229 self.putfr([4, ['Exiting overdrive mode', 'Overdrive off']])
230 self.overdrive = False
231 self.putfr([2, ['Reset', 'Rst', 'R']])
232 self.state = 'PRESENCE DETECT HIGH'
233 elif self.overdrive == True and \
234 time >= timing['RSTL']['min'][self.overdrive] and \
235 time < timing['RSTL']['max'][self.overdrive]:
236 # Overdrive reset pulse.
237 self.putfr([2, ['Reset', 'Rst', 'R']])
238 self.state = 'PRESENCE DETECT HIGH'
239 elif time < timing['SLOT']['max'][self.overdrive]:
240 # Read/write time slot.
241 if time < timing['LOWR']['min'][self.overdrive]:
242 self.putfr([1, ['Low signal not long enough',
244 'LOW < ' + str(timing['LOWR']['min'][self.overdrive])]])
245 if time < timing['LOWR']['max'][self.overdrive]:
246 self.bit = 1 # Short pulse is a 1 bit.
248 self.bit = 0 # Long pulse is a 0 bit.
249 # Wait for end of slot.
252 # Timing outside of known states.
253 self.putfr([1, ['Erroneous signal', 'Error', 'Err', 'E']])
255 elif self.state == 'PRESENCE DETECT HIGH': # Wait for slave presence signal.
256 # Wait for a falling edge and/or presence detect signal.
257 self.wait_falling_timeout(self.rise, timing['PDH']['max'])
259 # Calculate time since rising edge.
260 time = ((self.samplenum - self.rise) / self.samplerate) * 1000000.0
262 if self.matched[0] and not self.matched[1]:
264 if time < timing['PDH']['min'][self.overdrive]:
265 self.putrs([1, ['Presence detect signal is too early',
266 'Presence detect too early',
267 'PDH < ' + str(timing['PDH']['min'][self.overdrive])]])
268 self.fall = self.samplenum
269 self.state = 'PRESENCE DETECT LOW'
270 else: # No presence detected.
271 self.putrs([3, ['Presence: false', 'Presence', 'Pres', 'P']])
272 self.putprs(['RESET/PRESENCE', False])
274 elif self.state == 'PRESENCE DETECT LOW': # Slave presence signalled.
275 # Wait for end of presence signal (on rising edge).
277 # Calculate time since start of presence signal.
278 time = ((self.samplenum - self.fall) / self.samplerate) * 1000000.0
279 if time < timing['PDL']['min'][self.overdrive]:
280 self.putfs([1, ['Presence detect signal is too short',
281 'Presence detect too short',
282 'PDL < ' + str(timing['PDL']['min'][self.overdrive])]])
283 elif time > timing['PDL']['max'][self.overdrive]:
284 self.putfs([1, ['Presence detect signal is too long',
285 'Presence detect too long',
286 'PDL > ' + str(timing['PDL']['max'][self.overdrive])]])
287 if time > timing['RSTH']['min'][self.overdrive]:
288 self.rise = self.samplenum
289 # Wait for end of presence detect.
290 self.state = 'PRESENCE DETECT'
292 # End states (for additional checks).
293 if self.state == 'SLOT': # Wait for end of time slot.
294 # Wait for a falling edge and/or end of timeslot.
295 self.wait_falling_timeout(self.fall, timing['SLOT']['min'])
297 if self.matched[0] and not self.matched[1]:
298 # Low detected before end of slot.
299 self.putfs([1, ['Time slot not long enough',
301 'SLOT < ' + str(timing['SLOT']['min'][self.overdrive])]])
302 # Don't output invalid bit.
303 self.fall = self.samplenum
305 else: # End of time slot.
307 self.putfs([0, ['Bit: %d' % self.bit, '%d' % self.bit]])
308 self.putpfs(['BIT', self.bit])
310 if self.bit_count >= 0:
311 self.command += (self.bit << self.bit_count)
313 # Check for overdrive ROM command.
314 if self.bit_count >= 8:
315 if self.command == 0x3c or self.command == 0x69:
316 self.overdrive = True
317 self.put(self.samplenum, self.samplenum,
319 [4, ['Entering overdrive mode', 'Overdrive on']])
323 if self.state == 'PRESENCE DETECT':
324 # Wait for a falling edge and/or end of presence detect.
325 self.wait_falling_timeout(self.rise, timing['RSTH']['min'])
327 if self.matched[0] and not self.matched[1]:
328 # Low detected before end of presence detect.
329 self.putfs([1, ['Presence detect not long enough',
330 'Presence detect too short',
331 'RTSH < ' + str(timing['RSTH']['min'][self.overdrive])]])
332 # Inform about presence detected.
333 self.putrs([3, ['Slave presence detected', 'Slave present',
335 self.putprs(['RESET/PRESENCE', True])
336 self.fall = self.samplenum
338 else: # End of time slot.
339 # Inform about presence detected.
340 self.putrs([3, ['Presence: true', 'Presence', 'Pres', 'P']])
341 self.putprs(['RESET/PRESENCE', True])
342 self.rise = self.samplenum
343 # Start counting the first 8 bits to get the ROM command.