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'],
56 ['reset', 'Reset/presence'],
57 ['overdrive', 'Overdrive mode notifications'],
61 self.put(0, 0, self.out_ann, data)
63 def putpb(self, data):
64 self.put(self.fall, self.samplenum, self.out_proto, data)
67 self.put(self.fall, self.samplenum, self.out_ann, data)
70 self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, data)
72 def __init__(self, **kwargs):
74 self.state = 'WAIT FOR FALLING EDGE'
83 def start(self, metadata):
84 self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire_link')
85 self.out_ann = self.add(srd.OUTPUT_ANN, 'onewire_link')
87 self.samplerate = metadata['samplerate']
89 # Check if samplerate is appropriate.
90 if self.options['overdrive'] == 'yes':
91 if self.samplerate < 2000000:
92 self.putm([1, ['Sampling rate is too low. Must be above ' +
93 '2MHz for proper overdrive mode decoding.']])
94 elif self.samplerate < 5000000:
95 self.putm([1, ['Sampling rate is suggested to be above 5MHz ' +
96 'for proper overdrive mode decoding.']])
98 if self.samplerate < 400000:
99 self.putm([1, ['Sampling rate is too low. Must be above ' +
100 '400kHz for proper normal mode decoding.']])
101 elif (self.samplerate < 1000000):
102 self.putm([1, ['Sampling rate is suggested to be above ' +
103 '1MHz for proper normal mode decoding.']])
105 # The default 1-Wire time base is 30us. This is used to calculate
107 samplerate = float(self.samplerate)
109 x = float(self.options['cnt_normal_bit']) / 1000000.0
110 self.cnt_normal_bit = int(samplerate * x) - 1
111 x = float(self.options['cnt_normal_slot']) / 1000000.0
112 self.cnt_normal_slot = int(samplerate * x) - 1
113 x = float(self.options['cnt_normal_presence']) / 1000000.0
114 self.cnt_normal_presence = int(samplerate * x) - 1
115 x = float(self.options['cnt_normal_reset']) / 1000000.0
116 self.cnt_normal_reset = int(samplerate * x) - 1
117 x = float(self.options['cnt_overdrive_bit']) / 1000000.0
118 self.cnt_overdrive_bit = int(samplerate * x) - 1
119 x = float(self.options['cnt_overdrive_slot']) / 1000000.0
120 self.cnt_overdrive_slot = int(samplerate * x) - 1
121 x = float(self.options['cnt_overdrive_presence']) / 1000000.0
122 self.cnt_overdrive_presence = int(samplerate * x) - 1
123 x = float(self.options['cnt_overdrive_reset']) / 1000000.0
124 self.cnt_overdrive_reset = int(samplerate * x) - 1
126 # Organize values into lists.
127 self.cnt_bit = [self.cnt_normal_bit, self.cnt_overdrive_bit]
128 self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence]
129 self.cnt_reset = [self.cnt_normal_reset, self.cnt_overdrive_reset]
130 self.cnt_slot = [self.cnt_normal_slot, self.cnt_overdrive_slot]
132 # Check if sample times are in the allowed range.
134 time_min = float(self.cnt_normal_bit) / self.samplerate
135 time_max = float(self.cnt_normal_bit + 1) / self.samplerate
136 if (time_min < 0.000005) or (time_max > 0.000015):
137 self.putm([1, ['The normal mode data sample time interval ' +
138 '(%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).'
139 % (time_min * 1000000, time_max * 1000000)]])
141 time_min = float(self.cnt_normal_presence) / self.samplerate
142 time_max = float(self.cnt_normal_presence + 1) / self.samplerate
143 if (time_min < 0.0000681) or (time_max > 0.000075):
144 self.putm([1, ['The normal mode presence sample time interval ' +
145 '(%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).'
146 % (time_min * 1000000, time_max * 1000000)]])
148 time_min = float(self.cnt_overdrive_bit) / self.samplerate
149 time_max = float(self.cnt_overdrive_bit + 1) / self.samplerate
150 if (time_min < 0.000001) or (time_max > 0.000002):
151 self.putm([1, ['The overdrive mode data sample time interval ' +
152 '(%2.1fus-%2.1fus) should be inside (1.0us, 2.0us).'
153 % (time_min * 1000000, time_max * 1000000)]])
155 time_min = float(self.cnt_overdrive_presence) / self.samplerate
156 time_max = float(self.cnt_overdrive_presence + 1) / self.samplerate
157 if (time_min < 0.0000073) or (time_max > 0.000010):
158 self.putm([1, ['The overdrive mode presence sample time interval ' +
159 '(%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).'
160 % (time_min*1000000, time_max*1000000)]])
165 def decode(self, ss, es, data):
166 for (self.samplenum, (owr, pwr)) in data:
168 if self.state == 'WAIT FOR FALLING EDGE':
169 # The start of a cycle is a falling edge.
172 # Save the sample number for the falling edge.
173 self.fall = self.samplenum
174 # Go to waiting for sample time.
175 self.state = 'WAIT FOR DATA SAMPLE'
176 elif self.state == 'WAIT FOR DATA SAMPLE':
178 t = self.samplenum - self.fall
179 if t == self.cnt_bit[self.overdrive]:
181 self.state = 'WAIT FOR DATA SLOT END'
182 elif self.state == 'WAIT FOR DATA SLOT END':
183 # A data slot ends in a recovery period, otherwise, this is
185 t = self.samplenum - self.fall
186 if t != self.cnt_slot[self.overdrive]:
190 # This seems to be a reset slot, wait for its end.
191 self.state = 'WAIT FOR RISING EDGE'
194 self.putb([0, ['Bit: %d' % self.bit]])
195 self.putpb(['BIT', self.bit])
197 # Checking the first command to see if overdrive mode
199 if self.bit_cnt <= 8:
200 self.command |= (self.bit << self.bit_cnt)
201 elif self.bit_cnt == 8 and self.command in [0x3c, 0x69]:
202 self.putx([3, ['Entering overdrive mode']])
203 # Increment the bit counter.
205 # Wait for next slot.
206 self.state = 'WAIT FOR FALLING EDGE'
207 elif self.state == 'WAIT FOR RISING EDGE':
208 # The end of a cycle is a rising edge.
212 # Check if this was a reset cycle.
213 t = self.samplenum - self.fall
214 if t > self.cnt_normal_reset:
215 # Save the sample number for the falling edge.
216 self.rise = self.samplenum
217 self.state = 'WAIT FOR PRESENCE DETECT'
218 # Exit overdrive mode.
220 self.putx([3, ['Exiting overdrive mode']])
222 # Clear command bit counter and data register.
225 elif (t > self.cnt_overdrive_reset) and self.overdrive:
226 # Save the sample number for the falling edge.
227 self.rise = self.samplenum
228 self.state = "WAIT FOR PRESENCE DETECT"
229 # Otherwise this is assumed to be a data bit.
231 self.state = "WAIT FOR FALLING EDGE"
232 elif self.state == 'WAIT FOR PRESENCE DETECT':
233 # Sample presence status.
234 t = self.samplenum - self.rise
235 if t == self.cnt_presence[self.overdrive]:
237 self.state = 'WAIT FOR RESET SLOT END'
238 elif self.state == 'WAIT FOR RESET SLOT END':
239 # A reset slot ends in a long recovery period.
240 t = self.samplenum - self.rise
241 if t != self.cnt_reset[self.overdrive]:
245 # This seems to be a reset slot, wait for its end.
246 self.state = 'WAIT FOR RISING EDGE'
249 p = 'false' if self.present else 'true'
250 self.putb([2, ['Reset/presence: %s' % p]])
251 self.putpb(['RESET/PRESENCE', not self.present])
253 # Wait for next slot.
254 self.state = 'WAIT FOR FALLING EDGE'
256 raise Exception('Invalid state: %s' % self.state)