2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2012 Iztok Jeras <iztok.jeras@gmail.com>
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 class Decoder(srd.Decoder):
28 name = '1-Wire link layer'
29 longname = '1-Wire serial communication bus (link layer)'
30 desc = 'Bidirectional, half-duplex, asynchronous serial bus.'
33 outputs = ['onewire_link']
35 {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire signal line'},
38 {'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power supply pin'},
42 'desc': 'Overdrive mode', 'default': 'no', 'values': ('yes', 'no')},
43 # Time options (specified in microseconds):
44 {'id': 'cnt_normal_bit',
45 'desc': 'Normal mode sample bit time (μs)', 'default': 15},
46 {'id': 'cnt_normal_slot',
47 'desc': 'Normal mode data slot time (μs)', 'default': 60},
48 {'id': 'cnt_normal_presence',
49 'desc': 'Normal mode sample presence time (μs)', 'default': 75},
50 {'id': 'cnt_normal_reset',
51 'desc': 'Normal mode reset time (μs)', 'default': 480},
52 {'id': 'cnt_overdrive_bit',
53 'desc': 'Overdrive mode sample bit time (μs)', 'default': 2},
54 {'id': 'cnt_overdrive_slot',
55 'desc': 'Overdrive mode data slot time (μs)', 'default': 7.3},
56 {'id': 'cnt_overdrive_presence',
57 'desc': 'Overdrive mode sample presence time (μs)', 'default': 10},
58 {'id': 'cnt_overdrive_reset',
59 'desc': 'Overdrive mode reset time (μs)', 'default': 48},
63 ('warnings', 'Warnings'),
65 ('presence', 'Presence'),
66 ('overdrive', 'Overdrive mode notifications'),
69 ('bits', 'Bits', (0, 2, 3)),
70 ('info', 'Info', (4,)),
71 ('warnings', 'Warnings', (1,)),
75 self.put(0, 0, self.out_ann, data)
77 def putpb(self, data):
78 self.put(self.fall, self.samplenum, self.out_python, data)
81 self.put(self.fall, self.samplenum, self.out_ann, data)
84 self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, data)
86 def putfr(self, data):
87 self.put(self.fall, self.rise, self.out_ann, data)
89 def putprs(self, data):
90 self.put(self.rise, self.samplenum, self.out_python, data)
92 def putrs(self, data):
93 self.put(self.rise, self.samplenum, self.out_ann, data)
96 self.samplerate = None
97 self.state = 'WAIT FOR FALLING EDGE'
107 self.out_python = self.register(srd.OUTPUT_PYTHON)
108 self.out_ann = self.register(srd.OUTPUT_ANN)
110 self.initial_pins = [1, 1]
113 # Check if samplerate is appropriate.
114 if self.options['overdrive'] == 'yes':
115 if self.samplerate < 2000000:
116 self.putm([1, ['Sampling rate is too low. Must be above ' +
117 '2MHz for proper overdrive mode decoding.']])
118 elif self.samplerate < 5000000:
119 self.putm([1, ['Sampling rate is suggested to be above 5MHz ' +
120 'for proper overdrive mode decoding.']])
122 if self.samplerate < 400000:
123 self.putm([1, ['Sampling rate is too low. Must be above ' +
124 '400kHz for proper normal mode decoding.']])
125 elif self.samplerate < 1000000:
126 self.putm([1, ['Sampling rate is suggested to be above ' +
127 '1MHz for proper normal mode decoding.']])
129 # Check if sample times are in the allowed range.
131 time_min = float(self.cnt_normal_bit) / self.samplerate
132 time_max = float(self.cnt_normal_bit + 1) / self.samplerate
133 if (time_min < 0.000005) or (time_max > 0.000015):
134 self.putm([1, ['The normal mode data sample time interval ' +
135 '(%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).'
136 % (time_min * 1000000, time_max * 1000000)]])
138 time_min = float(self.cnt_normal_presence) / self.samplerate
139 time_max = float(self.cnt_normal_presence + 1) / self.samplerate
140 if (time_min < 0.0000681) or (time_max > 0.000075):
141 self.putm([1, ['The normal mode presence sample time interval ' +
142 '(%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).'
143 % (time_min * 1000000, time_max * 1000000)]])
145 time_min = float(self.cnt_overdrive_bit) / self.samplerate
146 time_max = float(self.cnt_overdrive_bit + 1) / self.samplerate
147 if (time_min < 0.000001) or (time_max > 0.000002):
148 self.putm([1, ['The overdrive mode data sample time interval ' +
149 '(%2.1fus-%2.1fus) should be inside (1.0us, 2.0us).'
150 % (time_min * 1000000, time_max * 1000000)]])
152 time_min = float(self.cnt_overdrive_presence) / self.samplerate
153 time_max = float(self.cnt_overdrive_presence + 1) / self.samplerate
154 if (time_min < 0.0000073) or (time_max > 0.000010):
155 self.putm([1, ['The overdrive mode presence sample time interval ' +
156 '(%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).'
157 % (time_min * 1000000, time_max * 1000000)]])
160 def metadata(self, key, value):
161 if key != srd.SRD_CONF_SAMPLERATE:
163 self.samplerate = value
165 # The default 1-Wire time base is 30us. This is used to calculate
167 samplerate = float(self.samplerate)
169 x = float(self.options['cnt_normal_bit']) / 1000000.0
170 self.cnt_normal_bit = int(samplerate * x) - 1
171 x = float(self.options['cnt_normal_slot']) / 1000000.0
172 self.cnt_normal_slot = int(samplerate * x) - 1
173 x = float(self.options['cnt_normal_presence']) / 1000000.0
174 self.cnt_normal_presence = int(samplerate * x) - 1
175 x = float(self.options['cnt_normal_reset']) / 1000000.0
176 self.cnt_normal_reset = int(samplerate * x) - 1
177 x = float(self.options['cnt_overdrive_bit']) / 1000000.0
178 self.cnt_overdrive_bit = int(samplerate * x) - 1
179 x = float(self.options['cnt_overdrive_slot']) / 1000000.0
180 self.cnt_overdrive_slot = int(samplerate * x) - 1
181 x = float(self.options['cnt_overdrive_presence']) / 1000000.0
182 self.cnt_overdrive_presence = int(samplerate * x) - 1
183 x = float(self.options['cnt_overdrive_reset']) / 1000000.0
184 self.cnt_overdrive_reset = int(samplerate * x) - 1
186 # Organize values into lists.
187 self.cnt_bit = [self.cnt_normal_bit, self.cnt_overdrive_bit]
188 self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence]
189 self.cnt_reset = [self.cnt_normal_reset, self.cnt_overdrive_reset]
190 self.cnt_slot = [self.cnt_normal_slot, self.cnt_overdrive_slot]
193 if not self.samplerate:
194 raise SamplerateError('Cannot decode without samplerate.')
198 if self.state == 'WAIT FOR FALLING EDGE':
199 # The start of a cycle is a falling edge on OWR.
201 # Save the sample number for the falling edge.
202 self.fall = self.samplenum
203 self.state = 'WAIT FOR DATA SAMPLE'
204 elif self.state == 'WAIT FOR DATA SAMPLE':
206 t = self.fall + self.cnt_bit[self.overdrive]
207 self.bit, pwr = self.wait({'skip': t - self.samplenum})
208 self.state = 'WAIT FOR DATA SLOT END'
209 elif self.state == 'WAIT FOR DATA SLOT END':
210 # A data slot ends in a recovery period, otherwise, this is
212 t = self.fall + self.cnt_slot[self.overdrive]
213 owr, pwr = self.wait({'skip': t - self.samplenum})
216 # This seems to be a reset slot, wait for its end.
217 self.state = 'WAIT FOR RISING EDGE'
220 self.putb([0, ['Bit: %d' % self.bit, '%d' % self.bit]])
221 self.putpb(['BIT', self.bit])
223 # Checking the first command to see if overdrive mode
225 if self.bit_cnt <= 8:
226 self.command |= (self.bit << self.bit_cnt)
227 elif self.bit_cnt == 8 and self.command in [0x3c, 0x69]:
228 self.putx([4, ['Entering overdrive mode', 'Overdrive on']])
229 # Increment the bit counter.
231 # Wait for next slot.
232 self.state = 'WAIT FOR FALLING EDGE'
233 elif self.state == 'WAIT FOR RISING EDGE':
234 # The end of a cycle is a rising edge.
237 # Check if this was a reset cycle.
238 t = self.samplenum - self.fall
239 if t > self.cnt_normal_reset:
240 # Save the sample number for the rising edge.
241 self.rise = self.samplenum
242 self.putfr([2, ['Reset', 'Rst', 'R']])
243 self.state = 'WAIT FOR PRESENCE DETECT'
244 # Exit overdrive mode.
246 self.putx([4, ['Exiting overdrive mode', 'Overdrive off']])
248 # Clear command bit counter and data register.
251 elif (t > self.cnt_overdrive_reset) and self.overdrive:
252 # Save the sample number for the rising edge.
253 self.rise = self.samplenum
254 self.putfr([2, ['Reset', 'Rst', 'R']])
255 self.state = 'WAIT FOR PRESENCE DETECT'
256 # Otherwise this is assumed to be a data bit.
258 self.state = 'WAIT FOR FALLING EDGE'
259 elif self.state == 'WAIT FOR PRESENCE DETECT':
260 # Sample presence status.
261 t = self.rise + self.cnt_presence[self.overdrive]
262 owr, pwr = self.wait({'skip': t - self.samplenum})
264 self.state = 'WAIT FOR RESET SLOT END'
265 elif self.state == 'WAIT FOR RESET SLOT END':
266 # A reset slot ends in a long recovery period.
267 t = self.rise + self.cnt_reset[self.overdrive]
268 owr, pwr = self.wait({'skip': t - self.samplenum})
271 # This seems to be a reset slot, wait for its end.
272 self.state = 'WAIT FOR RISING EDGE'
275 p = 'false' if self.present else 'true'
276 self.putrs([3, ['Presence: %s' % p, 'Presence', 'Pres', 'P']])
277 self.putprs(['RESET/PRESENCE', not self.present])
279 # Wait for next slot.
280 self.state = 'WAIT FOR FALLING EDGE'