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, write to the Free Software
18 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 import sigrokdecode as srd
23 class SamplerateError(Exception):
26 class Decoder(srd.Decoder):
29 name = '1-Wire link layer'
30 longname = '1-Wire serial communication bus (link layer)'
31 desc = 'Bidirectional, half-duplex, asynchronous serial bus.'
34 outputs = ['onewire_link']
36 {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire signal line'},
39 {'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power supply pin'},
43 'desc': 'Overdrive mode', 'default': 'no', 'values': ('yes', 'no')},
44 # Time options (specified in microseconds):
45 {'id': 'cnt_normal_bit',
46 'desc': 'Normal mode sample bit time (μs)', 'default': 15},
47 {'id': 'cnt_normal_slot',
48 'desc': 'Normal mode data slot time (μs)', 'default': 60},
49 {'id': 'cnt_normal_presence',
50 'desc': 'Normal mode sample presence time (μs)', 'default': 75},
51 {'id': 'cnt_normal_reset',
52 'desc': 'Normal mode reset time (μs)', 'default': 480},
53 {'id': 'cnt_overdrive_bit',
54 'desc': 'Overdrive mode sample bit time (μs)', 'default': 2},
55 {'id': 'cnt_overdrive_slot',
56 'desc': 'Overdrive mode data slot time (μs)', 'default': 7.3},
57 {'id': 'cnt_overdrive_presence',
58 'desc': 'Overdrive mode sample presence time (μs)', 'default': 10},
59 {'id': 'cnt_overdrive_reset',
60 'desc': 'Overdrive mode reset time (μs)', 'default': 48},
64 ('warnings', 'Warnings'),
66 ('presence', 'Presence'),
67 ('overdrive', 'Overdrive mode notifications'),
70 ('bits', 'Bits', (0, 2, 3)),
71 ('info', 'Info', (4,)),
72 ('warnings', 'Warnings', (1,)),
76 self.put(0, 0, self.out_ann, data)
78 def putpb(self, data):
79 self.put(self.fall, self.samplenum, self.out_python, data)
82 self.put(self.fall, self.samplenum, self.out_ann, data)
85 self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, data)
87 def putfr(self, data):
88 self.put(self.fall, self.rise, self.out_ann, data)
90 def putprs(self, data):
91 self.put(self.rise, self.samplenum, self.out_python, data)
93 def putrs(self, data):
94 self.put(self.rise, self.samplenum, self.out_ann, data)
97 self.samplerate = None
98 self.state = 'WAIT FOR FALLING EDGE'
108 self.out_python = self.register(srd.OUTPUT_PYTHON)
109 self.out_ann = self.register(srd.OUTPUT_ANN)
111 self.initial_pins = [1, 1]
114 # Check if samplerate is appropriate.
115 if self.options['overdrive'] == 'yes':
116 if self.samplerate < 2000000:
117 self.putm([1, ['Sampling rate is too low. Must be above ' +
118 '2MHz for proper overdrive mode decoding.']])
119 elif self.samplerate < 5000000:
120 self.putm([1, ['Sampling rate is suggested to be above 5MHz ' +
121 'for proper overdrive mode decoding.']])
123 if self.samplerate < 400000:
124 self.putm([1, ['Sampling rate is too low. Must be above ' +
125 '400kHz for proper normal mode decoding.']])
126 elif self.samplerate < 1000000:
127 self.putm([1, ['Sampling rate is suggested to be above ' +
128 '1MHz for proper normal mode decoding.']])
130 # Check if sample times are in the allowed range.
132 time_min = float(self.cnt_normal_bit) / self.samplerate
133 time_max = float(self.cnt_normal_bit + 1) / self.samplerate
134 if (time_min < 0.000005) or (time_max > 0.000015):
135 self.putm([1, ['The normal mode data sample time interval ' +
136 '(%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).'
137 % (time_min * 1000000, time_max * 1000000)]])
139 time_min = float(self.cnt_normal_presence) / self.samplerate
140 time_max = float(self.cnt_normal_presence + 1) / self.samplerate
141 if (time_min < 0.0000681) or (time_max > 0.000075):
142 self.putm([1, ['The normal mode presence sample time interval ' +
143 '(%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).'
144 % (time_min * 1000000, time_max * 1000000)]])
146 time_min = float(self.cnt_overdrive_bit) / self.samplerate
147 time_max = float(self.cnt_overdrive_bit + 1) / self.samplerate
148 if (time_min < 0.000001) or (time_max > 0.000002):
149 self.putm([1, ['The overdrive mode data sample time interval ' +
150 '(%2.1fus-%2.1fus) should be inside (1.0us, 2.0us).'
151 % (time_min * 1000000, time_max * 1000000)]])
153 time_min = float(self.cnt_overdrive_presence) / self.samplerate
154 time_max = float(self.cnt_overdrive_presence + 1) / self.samplerate
155 if (time_min < 0.0000073) or (time_max > 0.000010):
156 self.putm([1, ['The overdrive mode presence sample time interval ' +
157 '(%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).'
158 % (time_min * 1000000, time_max * 1000000)]])
161 def metadata(self, key, value):
162 if key != srd.SRD_CONF_SAMPLERATE:
164 self.samplerate = value
166 # The default 1-Wire time base is 30us. This is used to calculate
168 samplerate = float(self.samplerate)
170 x = float(self.options['cnt_normal_bit']) / 1000000.0
171 self.cnt_normal_bit = int(samplerate * x) - 1
172 x = float(self.options['cnt_normal_slot']) / 1000000.0
173 self.cnt_normal_slot = int(samplerate * x) - 1
174 x = float(self.options['cnt_normal_presence']) / 1000000.0
175 self.cnt_normal_presence = int(samplerate * x) - 1
176 x = float(self.options['cnt_normal_reset']) / 1000000.0
177 self.cnt_normal_reset = int(samplerate * x) - 1
178 x = float(self.options['cnt_overdrive_bit']) / 1000000.0
179 self.cnt_overdrive_bit = int(samplerate * x) - 1
180 x = float(self.options['cnt_overdrive_slot']) / 1000000.0
181 self.cnt_overdrive_slot = int(samplerate * x) - 1
182 x = float(self.options['cnt_overdrive_presence']) / 1000000.0
183 self.cnt_overdrive_presence = int(samplerate * x) - 1
184 x = float(self.options['cnt_overdrive_reset']) / 1000000.0
185 self.cnt_overdrive_reset = int(samplerate * x) - 1
187 # Organize values into lists.
188 self.cnt_bit = [self.cnt_normal_bit, self.cnt_overdrive_bit]
189 self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence]
190 self.cnt_reset = [self.cnt_normal_reset, self.cnt_overdrive_reset]
191 self.cnt_slot = [self.cnt_normal_slot, self.cnt_overdrive_slot]
194 if not self.samplerate:
195 raise SamplerateError('Cannot decode without samplerate.')
199 if self.state == 'WAIT FOR FALLING EDGE':
200 # The start of a cycle is a falling edge on OWR.
202 # Save the sample number for the falling edge.
203 self.fall = self.samplenum
204 self.state = 'WAIT FOR DATA SAMPLE'
205 elif self.state == 'WAIT FOR DATA SAMPLE':
207 t = self.fall + self.cnt_bit[self.overdrive]
208 self.bit, pwr = self.wait({'skip': t - self.samplenum})
209 self.state = 'WAIT FOR DATA SLOT END'
210 elif self.state == 'WAIT FOR DATA SLOT END':
211 # A data slot ends in a recovery period, otherwise, this is
213 t = self.fall + self.cnt_slot[self.overdrive]
214 owr, pwr = self.wait({'skip': t - self.samplenum})
217 # This seems to be a reset slot, wait for its end.
218 self.state = 'WAIT FOR RISING EDGE'
221 self.putb([0, ['Bit: %d' % self.bit, '%d' % self.bit]])
222 self.putpb(['BIT', self.bit])
224 # Checking the first command to see if overdrive mode
226 if self.bit_cnt <= 8:
227 self.command |= (self.bit << self.bit_cnt)
228 elif self.bit_cnt == 8 and self.command in [0x3c, 0x69]:
229 self.putx([4, ['Entering overdrive mode', 'Overdrive on']])
230 # Increment the bit counter.
232 # Wait for next slot.
233 self.state = 'WAIT FOR FALLING EDGE'
234 elif self.state == 'WAIT FOR RISING EDGE':
235 # The end of a cycle is a rising edge.
238 # Check if this was a reset cycle.
239 t = self.samplenum - self.fall
240 if t > self.cnt_normal_reset:
241 # Save the sample number for the rising edge.
242 self.rise = self.samplenum
243 self.putfr([2, ['Reset', 'Rst', 'R']])
244 self.state = 'WAIT FOR PRESENCE DETECT'
245 # Exit overdrive mode.
247 self.putx([4, ['Exiting overdrive mode', 'Overdrive off']])
249 # Clear command bit counter and data register.
252 elif (t > self.cnt_overdrive_reset) and self.overdrive:
253 # Save the sample number for the rising edge.
254 self.rise = self.samplenum
255 self.putfr([2, ['Reset', 'Rst', 'R']])
256 self.state = 'WAIT FOR PRESENCE DETECT'
257 # Otherwise this is assumed to be a data bit.
259 self.state = 'WAIT FOR FALLING EDGE'
260 elif self.state == 'WAIT FOR PRESENCE DETECT':
261 # Sample presence status.
262 t = self.rise + self.cnt_presence[self.overdrive]
263 owr, pwr = self.wait({'skip': t - self.samplenum})
265 self.state = 'WAIT FOR RESET SLOT END'
266 elif self.state == 'WAIT FOR RESET SLOT END':
267 # A reset slot ends in a long recovery period.
268 t = self.rise + self.cnt_reset[self.overdrive]
269 owr, pwr = self.wait({'skip': t - self.samplenum})
272 # This seems to be a reset slot, wait for its end.
273 self.state = 'WAIT FOR RISING EDGE'
276 p = 'false' if self.present else 'true'
277 self.putrs([3, ['Presence: %s' % p, 'Presence', 'Pres', 'P']])
278 self.putprs(['RESET/PRESENCE', not self.present])
280 # Wait for next slot.
281 self.state = 'WAIT FOR FALLING EDGE'