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')
140 def putm(self, data):
141 self.put(0, 0, self.out_ann, data)
143 def putpfs(self, data):
144 self.put(self.fall, self.samplenum, self.out_python, data)
146 def putfs(self, data):
147 self.put(self.fall, self.samplenum, self.out_ann, data)
149 def putfr(self, data):
150 self.put(self.fall, self.rise, self.out_ann, data)
152 def putprs(self, data):
153 self.put(self.rise, self.samplenum, self.out_python, data)
155 def putrs(self, data):
156 self.put(self.rise, self.samplenum, self.out_ann, data)
159 # Check if samplerate is appropriate.
160 if self.options['overdrive'] == 'yes':
161 if self.samplerate < 2000000:
162 self.putm([1, ['Sampling rate is too low. Must be above ' +
163 '2MHz for proper overdrive mode decoding.']])
164 elif self.samplerate < 5000000:
165 self.putm([1, ['Sampling rate is suggested to be above 5MHz ' +
166 'for proper overdrive mode decoding.']])
168 if self.samplerate < 400000:
169 self.putm([1, ['Sampling rate is too low. Must be above ' +
170 '400kHz for proper normal mode decoding.']])
171 elif self.samplerate < 1000000:
172 self.putm([1, ['Sampling rate is suggested to be above ' +
173 '1MHz for proper normal mode decoding.']])
175 def metadata(self, key, value):
176 if key != srd.SRD_CONF_SAMPLERATE:
178 self.samplerate = value
180 def decode(self, ss, es, data):
181 if not self.samplerate:
182 raise SamplerateError('Cannot decode without samplerate.')
183 for (self.samplenum, (owr,)) in data:
184 if self.samplenum == 0:
188 if self.state == 'INITIAL': # Unknown initial state.
189 # Wait until we reach the idle high state.
192 self.rise = self.samplenum
194 elif self.state == 'IDLE': # Idle high state.
195 # Wait for falling edge.
198 self.fall = self.samplenum
199 # Get time since last rising edge.
200 time = ((self.fall - self.rise) / self.samplerate) * 1000000.0
201 if self.rise > 0 and \
202 time < timing['REC']['min'][self.overdrive]:
203 self.putfr([1, ['Recovery time not long enough'
204 'Recovery too short',
205 'REC < ' + str(timing['REC']['min'][self.overdrive])]])
206 # A reset pulse or slot can start on a falling edge.
208 # TODO: Check minimum recovery time.
209 elif self.state == 'LOW': # Reset pulse or slot.
210 # Wait for rising edge.
213 self.rise = self.samplenum
214 # Detect reset or slot base on timing.
215 time = ((self.rise - self.fall) / self.samplerate) * 1000000.0
216 if time >= timing['RSTL']['min'][False]: # Normal reset pulse.
217 if time > timing['RSTL']['max'][False]:
218 self.putfr([1, ['Too long reset pulse might mask interrupt ' +
219 'signalling by other devices',
220 'Reset pulse too long',
221 'RST > ' + str(timing['RSTL']['max'][False])]])
222 # Regular reset pulse clears overdrive speed.
224 self.putfr([4, ['Exiting overdrive mode', 'Overdrive off']])
225 self.overdrive = False
226 self.putfr([2, ['Reset', 'Rst', 'R']])
227 self.state = 'PRESENCE DETECT HIGH'
228 elif self.overdrive == True and \
229 time >= timing['RSTL']['min'][self.overdrive] and \
230 time < timing['RSTL']['max'][self.overdrive]:
231 # Overdrive reset pulse.
232 self.putfr([2, ['Reset', 'Rst', 'R']])
233 self.state = 'PRESENCE DETECT HIGH'
234 elif time < timing['SLOT']['max'][self.overdrive]:
235 # Read/write time slot.
236 if time < timing['LOWR']['min'][self.overdrive]:
237 self.putfr([1, ['Low signal not long enough',
239 'LOW < ' + str(timing['LOWR']['min'][self.overdrive])]])
240 if time < timing['LOWR']['max'][self.overdrive]:
241 self.bit = 1 # Short pulse is a 1 bit.
243 self.bit = 0 # Long pulse is a 0 bit.
244 # Wait for end of slot.
247 # Timing outside of known states.
248 self.putfr([1, ['Erroneous signal', 'Error', 'Err', 'E']])
250 elif self.state == 'PRESENCE DETECT HIGH': # Wait for slave presence signal.
251 # Calculate time since rising edge.
252 time = ((self.samplenum - self.rise) / self.samplerate) * 1000000.0
253 if owr != 0 and time < timing['PDH']['max'][self.overdrive]:
255 elif owr == 0: # Presence detected.
256 if time < timing['PDH']['min'][self.overdrive]:
257 self.putrs([1, ['Presence detect signal is too early',
258 'Presence detect too early',
259 'PDH < ' + str(timing['PDH']['min'][self.overdrive])]])
260 self.fall = self.samplenum
261 self.state = 'PRESENCE DETECT LOW'
262 else: # No presence detected.
263 self.putrs([3, ['Presence: false', 'Presence', 'Pres', 'P']])
264 self.putprs(['RESET/PRESENCE', False])
266 elif self.state == 'PRESENCE DETECT LOW': # Slave presence signalled.
267 # Wait for end of presence signal (on rising edge).
270 # Calculate time since start of presence signal.
271 time = ((self.samplenum - self.fall) / self.samplerate) * 1000000.0
272 if time < timing['PDL']['min'][self.overdrive]:
273 self.putfs([1, ['Presence detect signal is too short',
274 'Presence detect too short',
275 'PDL < ' + str(timing['PDL']['min'][self.overdrive])]])
276 elif time > timing['PDL']['max'][self.overdrive]:
277 self.putfs([1, ['Presence detect signal is too long',
278 'Presence detect too long',
279 'PDL > ' + str(timing['PDL']['max'][self.overdrive])]])
280 if time > timing['RSTH']['min'][self.overdrive]:
281 self.rise = self.samplenum
282 # Wait for end of presence detect.
283 self.state = 'PRESENCE DETECT'
285 # End states (for additional checks).
286 if self.state == 'SLOT': # Wait for end of time slot.
287 # Calculate time since falling edge.
288 time = ((self.samplenum - self.fall) / self.samplerate) * 1000000.0
289 if owr != 0 and time < timing['SLOT']['min'][self.overdrive]:
291 elif owr == 0: # Low detected before end of slot.
292 # Warn about irregularity.
293 self.putfs([1, ['Time slot not long enough',
295 'SLOT < ' + str(timing['SLOT']['min'][self.overdrive])]])
296 # Don't output invalid bit.
297 self.fall = self.samplenum
299 else: # End of time slot.
301 self.putfs([0, ['Bit: %d' % self.bit, '%d' % self.bit]])
302 self.putpfs(['BIT', self.bit])
304 if self.bit_count >= 0:
305 self.command += (self.bit << self.bit_count)
307 # Check for overdrive ROM command.
308 if self.bit_count >= 8:
309 if self.command == 0x3c or self.command == 0x69:
310 self.overdrive = True
311 self.put(self.samplenum, self.samplenum,
313 [4, ['Entering overdrive mode', 'Overdrive on']])
317 if self.state == 'PRESENCE DETECT':
318 # Wait for end of presence detect.
319 # Calculate time since falling edge.
320 time = ((self.samplenum - self.rise) / self.samplerate) * 1000000.0
321 if owr != 0 and time < timing['RSTH']['min'][self.overdrive]:
323 elif owr == 0: # Low detected before end of presence detect.
324 # Warn about irregularity.
325 self.putfs([1, ['Presence detect not long enough',
326 'Presence detect too short',
327 'RTSH < ' + str(timing['RSTH']['min'][self.overdrive])]])
328 # Inform about presence detected.
329 self.putrs([3, ['Slave presence detected', 'Slave present',
331 self.putprs(['RESET/PRESENCE', True])
332 self.fall = self.samplenum
334 else: # End of time slot.
335 # Inform about presence detected.
336 self.putrs([3, ['Presence: true', 'Presence', 'Pres', 'P']])
337 self.putprs(['RESET/PRESENCE', True])
338 self.rise = self.samplenum
339 # Start counting the first 8 bits to get the ROM command.