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', 1],
42 # Time options (specified in number of samplerate periods):
43 'cnt_normal_bit': ['Normal mode sample bit time', 0],
44 'cnt_normal_slot': ['Normal mode data slot time', 0],
45 'cnt_normal_presence': ['Normal mode sample presence time', 0],
46 'cnt_normal_reset': ['Normal mode reset time', 0],
47 'cnt_overdrive_bit': ['Overdrive mode sample bit time', 0],
48 'cnt_overdrive_slot': ['Overdrive mode data slot time', 0],
49 'cnt_overdrive_presence': ['Overdrive mode sample presence time', 0],
50 'cnt_overdrive_reset': ['Overdrive mode reset time', 0],
53 ['Text', 'Human-readable text'],
54 ['Warnings', 'Human-readable warnings'],
58 self.put(0, 0, self.out_ann, data)
60 def putpb(self, data):
61 self.put(self.fall, self.samplenum, self.out_proto, data)
64 self.put(self.fall, self.samplenum, self.out_ann, data)
67 self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, data)
69 def __init__(self, **kwargs):
71 self.state = 'WAIT FOR FALLING EDGE'
80 def start(self, metadata):
81 self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire_link')
82 self.out_ann = self.add(srd.OUTPUT_ANN, 'onewire_link')
84 self.samplerate = metadata['samplerate']
86 # Check if samplerate is appropriate.
87 if self.options['overdrive']:
88 if self.samplerate < 2000000:
89 self.putm([1, ['Sampling rate is too low. Must be above ' +
90 '2MHz for proper overdrive mode decoding.']])
91 elif self.samplerate < 5000000:
92 self.putm([1, ['Sampling rate is suggested to be above 5MHz ' +
93 'for proper overdrive mode decoding.']])
95 if self.samplerate < 400000:
96 self.putm([1, ['Sampling rate is too low. Must be above ' +
97 '400kHz for proper normal mode decoding.']])
98 elif (self.samplerate < 1000000):
99 self.putm([1, ['Sampling rate is suggested to be above ' +
100 '1MHz for proper normal mode decoding.']])
102 # The default 1-Wire time base is 30us. This is used to calculate
104 samplerate = float(self.samplerate)
105 if self.options['cnt_normal_bit']:
106 self.cnt_normal_bit = self.options['cnt_normal_bit']
108 self.cnt_normal_bit = int(samplerate * 0.000015) - 1 # 15ns
109 if self.options['cnt_normal_slot']:
110 self.cnt_normal_slot = self.options['cnt_normal_slot']
112 self.cnt_normal_slot = int(samplerate * 0.000060) - 1 # 60ns
113 if self.options['cnt_normal_presence']:
114 self.cnt_normal_presence = self.options['cnt_normal_presence']
116 self.cnt_normal_presence = int(samplerate * 0.000075) - 1 # 75ns
117 if self.options['cnt_normal_reset']:
118 self.cnt_normal_reset = self.options['cnt_normal_reset']
120 self.cnt_normal_reset = int(samplerate * 0.000480) - 1 # 480ns
121 if self.options['cnt_overdrive_bit']:
122 self.cnt_overdrive_bit = self.options['cnt_overdrive_bit']
124 self.cnt_overdrive_bit = int(samplerate * 0.000002) - 1 # 2ns
125 if self.options['cnt_overdrive_slot']:
126 self.cnt_overdrive_slot = self.options['cnt_overdrive_slot']
128 self.cnt_overdrive_slot = int(samplerate * 0.0000073) - 1 # 6ns+1.3ns
129 if self.options['cnt_overdrive_presence']:
130 self.cnt_overdrive_presence = self.options['cnt_overdrive_presence']
132 self.cnt_overdrive_presence = int(samplerate * 0.000010) - 1 # 10ns
133 if self.options['cnt_overdrive_reset']:
134 self.cnt_overdrive_reset = self.options['cnt_overdrive_reset']
136 self.cnt_overdrive_reset = int(samplerate * 0.000048) - 1 # 48ns
138 # Organize values into lists.
139 self.cnt_bit = [self.cnt_normal_bit, self.cnt_overdrive_bit]
140 self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence]
141 self.cnt_reset = [self.cnt_normal_reset, self.cnt_overdrive_reset]
142 self.cnt_slot = [self.cnt_normal_slot, self.cnt_overdrive_slot]
144 # Check if sample times are in the allowed range.
146 time_min = float(self.cnt_normal_bit) / self.samplerate
147 time_max = float(self.cnt_normal_bit + 1) / self.samplerate
148 if (time_min < 0.000005) or (time_max > 0.000015):
149 self.putm([1, ['The normal mode data sample time interval ' +
150 '(%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).'
151 % (time_min * 1000000, time_max * 1000000)]])
153 time_min = float(self.cnt_normal_presence) / self.samplerate
154 time_max = float(self.cnt_normal_presence + 1) / self.samplerate
155 if (time_min < 0.0000681) or (time_max > 0.000075):
156 self.putm([1, ['The normal mode presence sample time interval ' +
157 '(%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).'
158 % (time_min * 1000000, time_max * 1000000)]])
160 time_min = float(self.cnt_overdrive_bit) / self.samplerate
161 time_max = float(self.cnt_overdrive_bit + 1) / self.samplerate
162 if (time_min < 0.000001) or (time_max > 0.000002):
163 self.putm([1, ['The overdrive mode data sample time interval ' +
164 '(%2.1fus-%2.1fus) should be inside (1.0us, 2.0us).'
165 % (time_min * 1000000, time_max * 1000000)]])
167 time_min = float(self.cnt_overdrive_presence) / self.samplerate
168 time_max = float(self.cnt_overdrive_presence + 1) / self.samplerate
169 if (time_min < 0.0000073) or (time_max > 0.000010):
170 self.putm([1, ['The overdrive mode presence sample time interval ' +
171 '(%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).'
172 % (time_min*1000000, time_max*1000000)]])
177 def decode(self, ss, es, data):
178 for (self.samplenum, (owr, pwr)) in data:
180 if self.state == 'WAIT FOR FALLING EDGE':
181 # The start of a cycle is a falling edge.
184 # Save the sample number for the falling edge.
185 self.fall = self.samplenum
186 # Go to waiting for sample time.
187 self.state = 'WAIT FOR DATA SAMPLE'
188 elif self.state == 'WAIT FOR DATA SAMPLE':
190 t = self.samplenum - self.fall
191 if t == self.cnt_bit[self.overdrive]:
193 self.state = 'WAIT FOR DATA SLOT END'
194 elif self.state == 'WAIT FOR DATA SLOT END':
195 # A data slot ends in a recovery period, otherwise, this is
197 t = self.samplenum - self.fall
198 if t != self.cnt_slot[self.overdrive]:
202 # This seems to be a reset slot, wait for its end.
203 self.state = 'WAIT FOR RISING EDGE'
206 self.putb([0, ['Bit: %d' % self.bit]])
207 self.putpb(['BIT', self.bit])
209 # Checking the first command to see if overdrive mode
211 if self.bit_cnt <= 8:
212 self.command |= (self.bit << self.bit_cnt)
213 elif self.bit_cnt == 8 and self.command in [0x3c, 0x69]:
214 self.putx([0, ['Entering overdrive mode']])
215 # Increment the bit counter.
217 # Wait for next slot.
218 self.state = 'WAIT FOR FALLING EDGE'
219 elif self.state == 'WAIT FOR RISING EDGE':
220 # The end of a cycle is a rising edge.
224 # Check if this was a reset cycle.
225 t = self.samplenum - self.fall
226 if t > self.cnt_normal_reset:
227 # Save the sample number for the falling edge.
228 self.rise = self.samplenum
229 self.state = 'WAIT FOR PRESENCE DETECT'
230 # Exit overdrive mode.
232 self.putx([0, ['Exiting overdrive mode']])
234 # Clear command bit counter and data register.
237 elif (t > self.cnt_overdrive_reset) and self.overdrive:
238 # Save the sample number for the falling edge.
239 self.rise = self.samplenum
240 self.state = "WAIT FOR PRESENCE DETECT"
241 # Otherwise this is assumed to be a data bit.
243 self.state = "WAIT FOR FALLING EDGE"
244 elif self.state == 'WAIT FOR PRESENCE DETECT':
245 # Sample presence status.
246 t = self.samplenum - self.rise
247 if t == self.cnt_presence[self.overdrive]:
249 self.state = 'WAIT FOR RESET SLOT END'
250 elif self.state == 'WAIT FOR RESET SLOT END':
251 # A reset slot ends in a long recovery period.
252 t = self.samplenum - self.rise
253 if t != self.cnt_reset[self.overdrive]:
257 # This seems to be a reset slot, wait for its end.
258 self.state = 'WAIT FOR RISING EDGE'
261 p = 'false' if self.present else 'true'
262 self.putb([0, ['Reset/presence: %s' % p]])
263 self.putpb(['RESET/PRESENCE', not self.present])
265 # Wait for next slot.
266 self.state = 'WAIT FOR FALLING EDGE'
268 raise Exception('Invalid state: %s' % self.state)