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 # 1-Wire protocol decoder (link layer)
23 import sigrokdecode as srd
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'},
41 'overdrive': ['Overdrive mode', 'no'],
42 # Time options (specified in microseconds):
43 'cnt_normal_bit': ['Normal mode sample bit time (us)', 15],
44 'cnt_normal_slot': ['Normal mode data slot time (us)', 60],
45 'cnt_normal_presence': ['Normal mode sample presence time (us)', 75],
46 'cnt_normal_reset': ['Normal mode reset time (us)', 480],
47 'cnt_overdrive_bit': ['Overdrive mode sample bit time (us)', 2],
48 # 'cnt_overdrive_slot': ['Overdrive mode data slot time (us)', 7.3],
49 'cnt_overdrive_slot': ['Overdrive mode data slot time (us)', 7],
50 'cnt_overdrive_presence': ['Overdrive mode sample presence time (us)', 10],
51 'cnt_overdrive_reset': ['Overdrive mode reset time (us)', 48],
55 ['warnings', 'Warnings'],
57 ['presence', 'Presence'],
58 ['overdrive', 'Overdrive mode notifications'],
62 self.put(0, 0, self.out_ann, data)
64 def putpb(self, data):
65 self.put(self.fall, self.samplenum, self.out_proto, data)
68 self.put(self.fall, self.samplenum, self.out_ann, data)
71 self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, data)
73 def putfr(self, data):
74 self.put(self.fall, self.rise, self.out_ann, data)
76 def putprs(self, data):
77 self.put(self.rise, self.samplenum, self.out_proto, data)
79 def putrs(self, data):
80 self.put(self.rise, self.samplenum, self.out_ann, data)
82 def __init__(self, **kwargs):
83 self.samplerate = None
85 self.state = 'WAIT FOR FALLING EDGE'
95 self.out_proto = self.register(srd.OUTPUT_PYTHON)
96 self.out_ann = self.register(srd.OUTPUT_ANN)
98 def metadata(self, key, value):
99 if key != srd.SRD_CONF_SAMPLERATE:
101 self.samplerate = value
103 # Check if samplerate is appropriate.
104 if self.options['overdrive'] == 'yes':
105 if self.samplerate < 2000000:
106 self.putm([1, ['Sampling rate is too low. Must be above ' +
107 '2MHz for proper overdrive mode decoding.']])
108 elif self.samplerate < 5000000:
109 self.putm([1, ['Sampling rate is suggested to be above 5MHz ' +
110 'for proper overdrive mode decoding.']])
112 if self.samplerate < 400000:
113 self.putm([1, ['Sampling rate is too low. Must be above ' +
114 '400kHz for proper normal mode decoding.']])
115 elif (self.samplerate < 1000000):
116 self.putm([1, ['Sampling rate is suggested to be above ' +
117 '1MHz for proper normal mode decoding.']])
119 # The default 1-Wire time base is 30us. This is used to calculate
121 samplerate = float(self.samplerate)
123 x = float(self.options['cnt_normal_bit']) / 1000000.0
124 self.cnt_normal_bit = int(samplerate * x) - 1
125 x = float(self.options['cnt_normal_slot']) / 1000000.0
126 self.cnt_normal_slot = int(samplerate * x) - 1
127 x = float(self.options['cnt_normal_presence']) / 1000000.0
128 self.cnt_normal_presence = int(samplerate * x) - 1
129 x = float(self.options['cnt_normal_reset']) / 1000000.0
130 self.cnt_normal_reset = int(samplerate * x) - 1
131 x = float(self.options['cnt_overdrive_bit']) / 1000000.0
132 self.cnt_overdrive_bit = int(samplerate * x) - 1
133 x = float(self.options['cnt_overdrive_slot']) / 1000000.0
134 self.cnt_overdrive_slot = int(samplerate * x) - 1
135 x = float(self.options['cnt_overdrive_presence']) / 1000000.0
136 self.cnt_overdrive_presence = int(samplerate * x) - 1
137 x = float(self.options['cnt_overdrive_reset']) / 1000000.0
138 self.cnt_overdrive_reset = int(samplerate * x) - 1
140 # Organize values into lists.
141 self.cnt_bit = [self.cnt_normal_bit, self.cnt_overdrive_bit]
142 self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence]
143 self.cnt_reset = [self.cnt_normal_reset, self.cnt_overdrive_reset]
144 self.cnt_slot = [self.cnt_normal_slot, self.cnt_overdrive_slot]
146 # Check if sample times are in the allowed range.
148 time_min = float(self.cnt_normal_bit) / self.samplerate
149 time_max = float(self.cnt_normal_bit + 1) / self.samplerate
150 if (time_min < 0.000005) or (time_max > 0.000015):
151 self.putm([1, ['The normal mode data sample time interval ' +
152 '(%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).'
153 % (time_min * 1000000, time_max * 1000000)]])
155 time_min = float(self.cnt_normal_presence) / self.samplerate
156 time_max = float(self.cnt_normal_presence + 1) / self.samplerate
157 if (time_min < 0.0000681) or (time_max > 0.000075):
158 self.putm([1, ['The normal mode presence sample time interval ' +
159 '(%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).'
160 % (time_min * 1000000, time_max * 1000000)]])
162 time_min = float(self.cnt_overdrive_bit) / self.samplerate
163 time_max = float(self.cnt_overdrive_bit + 1) / self.samplerate
164 if (time_min < 0.000001) or (time_max > 0.000002):
165 self.putm([1, ['The overdrive mode data sample time interval ' +
166 '(%2.1fus-%2.1fus) should be inside (1.0us, 2.0us).'
167 % (time_min * 1000000, time_max * 1000000)]])
169 time_min = float(self.cnt_overdrive_presence) / self.samplerate
170 time_max = float(self.cnt_overdrive_presence + 1) / self.samplerate
171 if (time_min < 0.0000073) or (time_max > 0.000010):
172 self.putm([1, ['The overdrive mode presence sample time interval ' +
173 '(%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).'
174 % (time_min*1000000, time_max*1000000)]])
179 def decode(self, ss, es, data):
180 if self.samplerate is None:
181 raise Exception("Cannot decode without samplerate.")
182 for (self.samplenum, (owr, pwr)) in data:
184 if self.state == 'WAIT FOR FALLING EDGE':
185 # The start of a cycle is a falling edge.
188 # Save the sample number for the falling edge.
189 self.fall = self.samplenum
190 # Go to waiting for sample time.
191 self.state = 'WAIT FOR DATA SAMPLE'
192 elif self.state == 'WAIT FOR DATA SAMPLE':
194 t = self.samplenum - self.fall
195 if t == self.cnt_bit[self.overdrive]:
197 self.state = 'WAIT FOR DATA SLOT END'
198 elif self.state == 'WAIT FOR DATA SLOT END':
199 # A data slot ends in a recovery period, otherwise, this is
201 t = self.samplenum - self.fall
202 if t != self.cnt_slot[self.overdrive]:
206 # This seems to be a reset slot, wait for its end.
207 self.state = 'WAIT FOR RISING EDGE'
210 self.putb([0, ['Bit: %d' % self.bit, '%d' % self.bit]])
211 self.putpb(['BIT', self.bit])
213 # Checking the first command to see if overdrive mode
215 if self.bit_cnt <= 8:
216 self.command |= (self.bit << self.bit_cnt)
217 elif self.bit_cnt == 8 and self.command in [0x3c, 0x69]:
218 self.putx([4, ['Entering overdrive mode', 'Overdrive on']])
219 # Increment the bit counter.
221 # Wait for next slot.
222 self.state = 'WAIT FOR FALLING EDGE'
223 elif self.state == 'WAIT FOR RISING EDGE':
224 # The end of a cycle is a rising edge.
228 # Check if this was a reset cycle.
229 t = self.samplenum - self.fall
230 if t > self.cnt_normal_reset:
231 # Save the sample number for the rising edge.
232 self.rise = self.samplenum
233 self.putfr([2, ['Reset', 'Rst', 'R']])
234 self.state = 'WAIT FOR PRESENCE DETECT'
235 # Exit overdrive mode.
237 self.putx([4, ['Exiting overdrive mode', 'Overdrive off']])
239 # Clear command bit counter and data register.
242 elif (t > self.cnt_overdrive_reset) and self.overdrive:
243 # Save the sample number for the rising edge.
244 self.rise = self.samplenum
245 self.putfr([2, ['Reset', 'Rst', 'R']])
246 self.state = "WAIT FOR PRESENCE DETECT"
247 # Otherwise this is assumed to be a data bit.
249 self.state = "WAIT FOR FALLING EDGE"
250 elif self.state == 'WAIT FOR PRESENCE DETECT':
251 # Sample presence status.
252 t = self.samplenum - self.rise
253 if t == self.cnt_presence[self.overdrive]:
255 self.state = 'WAIT FOR RESET SLOT END'
256 elif self.state == 'WAIT FOR RESET SLOT END':
257 # A reset slot ends in a long recovery period.
258 t = self.samplenum - self.rise
259 if t != self.cnt_reset[self.overdrive]:
263 # This seems to be a reset slot, wait for its end.
264 self.state = 'WAIT FOR RISING EDGE'
267 p = 'false' if self.present else 'true'
268 self.putrs([3, ['Presence: %s' % p, 'Presence', 'Pres', 'P']])
269 self.putprs(['RESET/PRESENCE', not self.present])
271 # Wait for next slot.
272 self.state = 'WAIT FOR FALLING EDGE'
274 raise Exception('Invalid state: %s' % self.state)