2 ## This file is part of the sigrok 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 bus'},
38 {'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power'},
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 ['Link', 'Link layer events (reset, presence, bit slots)'],
56 def __init__(self, **kwargs):
58 # Link layer variables
59 self.state = 'WAIT FOR FALLING EDGE'
65 # Event timing variables
69 def start(self, metadata):
70 self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire_link')
71 self.out_ann = self.add(srd.OUTPUT_ANN, 'onewire_link')
73 self.samplerate = metadata['samplerate']
75 # Check if samplerate is appropriate.
76 if self.options['overdrive']:
77 self.put(0, 0, self.out_ann, [0,
78 ['NOTE: Sample rate checks assume overdrive mode.']])
79 if self.samplerate < 2000000:
80 self.put(0, 0, self.out_ann, [0,
81 ['ERROR: Sampling rate is too low. Must be above 2MHz ' +
82 'for proper overdrive mode decoding.']])
83 elif self.samplerate < 5000000:
84 self.put(0, 0, self.out_ann, [0,
85 ['WARNING: Sampling rate is suggested to be above 5MHz ' +
86 'for proper overdrive mode decoding.']])
88 self.put(0, 0, self.out_ann, [0,
89 ['NOTE: Sample rate checks assume normal mode only.']])
90 if self.samplerate < 400000:
91 self.put(0, 0, self.out_ann, [0,
92 ['ERROR: Sampling rate is too low. Must be above ' +
93 '400kHz for proper normal mode decoding.']])
94 elif (self.samplerate < 1000000):
95 self.put(0, 0, self.out_ann, [0,
96 ['WARNING: Sampling rate is suggested to be above ' +
97 '1MHz for proper normal mode decoding.']])
99 # The default 1-Wire time base is 30us. This is used to calculate
101 samplerate = float(self.samplerate)
102 if self.options['cnt_normal_bit']:
103 self.cnt_normal_bit = self.options['cnt_normal_bit']
105 self.cnt_normal_bit = int(samplerate * 0.000015) - 1 # 15ns
106 if self.options['cnt_normal_slot']:
107 self.cnt_normal_slot = self.options['cnt_normal_slot']
109 self.cnt_normal_slot = int(samplerate * 0.000060) - 1 # 60ns
110 if self.options['cnt_normal_presence']:
111 self.cnt_normal_presence = self.options['cnt_normal_presence']
113 self.cnt_normal_presence = int(samplerate * 0.000075) - 1 # 75ns
114 if self.options['cnt_normal_reset']:
115 self.cnt_normal_reset = self.options['cnt_normal_reset']
117 self.cnt_normal_reset = int(samplerate * 0.000480) - 1 # 480ns
118 if self.options['cnt_overdrive_bit']:
119 self.cnt_overdrive_bit = self.options['cnt_overdrive_bit']
121 self.cnt_overdrive_bit = int(samplerate * 0.000002) - 1 # 2ns
122 if self.options['cnt_overdrive_slot']:
123 self.cnt_overdrive_slot = self.options['cnt_overdrive_slot']
125 self.cnt_overdrive_slot = int(samplerate * 0.0000073) - 1 # 6ns+1.3ns
126 if self.options['cnt_overdrive_presence']:
127 self.cnt_overdrive_presence = self.options['cnt_overdrive_presence']
129 self.cnt_overdrive_presence = int(samplerate * 0.000010) - 1 # 10ns
130 if self.options['cnt_overdrive_reset']:
131 self.cnt_overdrive_reset = self.options['cnt_overdrive_reset']
133 self.cnt_overdrive_reset = int(samplerate * 0.000048) - 1 # 48ns
135 # Organize values into lists.
136 self.cnt_bit = [self.cnt_normal_bit, self.cnt_overdrive_bit]
137 self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence]
138 self.cnt_reset = [self.cnt_normal_reset, self.cnt_overdrive_reset]
139 self.cnt_slot = [self.cnt_normal_slot, self.cnt_overdrive_slot]
141 # Check if sample times are in the allowed range.
143 time_min = float(self.cnt_normal_bit) / self.samplerate
144 time_max = float(self.cnt_normal_bit + 1) / self.samplerate
145 if (time_min < 0.000005) or (time_max > 0.000015):
146 self.put(0, 0, self.out_ann, [0,
147 ['WARNING: The normal mode data sample time interval ' +
148 '(%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).'
149 % (time_min * 1000000, time_max * 1000000)]])
151 time_min = float(self.cnt_normal_presence) / self.samplerate
152 time_max = float(self.cnt_normal_presence + 1) / self.samplerate
153 if (time_min < 0.0000681) or (time_max > 0.000075):
154 self.put(0, 0, self.out_ann, [0,
155 ['WARNING: The normal mode presence sample time interval ' +
156 '(%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).'
157 % (time_min * 1000000, time_max * 1000000)]])
159 time_min = float(self.cnt_overdrive_bit) / self.samplerate
160 time_max = float(self.cnt_overdrive_bit + 1) / self.samplerate
161 if (time_min < 0.000001) or (time_max > 0.000002):
162 self.put(0, 0, self.out_ann, [0,
163 ['WARNING: 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.put(0, 0, self.out_ann, [0,
171 ['WARNING: The overdrive mode presence sample time interval ' +
172 '(%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).'
173 % (time_min*1000000, time_max*1000000)]])
178 def decode(self, ss, es, data):
179 for (self.samplenum, (owr, pwr)) in data:
181 if self.state == 'WAIT FOR FALLING EDGE':
182 # 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]:
200 self.put(self.fall, self.samplenum, self.out_ann,
201 [0, ['BIT: %01x' % self.bit]])
202 self.put(self.fall, self.samplenum, self.out_proto,
205 # Checking the first command to see if overdrive mode
207 if self.bit_cnt <= 8:
208 self.command |= (self.bit << self.bit_cnt)
209 elif self.bit_cnt == 8 and self.command in [0x3c, 0x69]:
210 self.put(self.fall, self.cnt_bit[self.overdrive],
212 [0, ['ENTER OVERDRIVE MODE']])
213 # Increment the bit counter.
215 # Wait for next slot.
216 self.state = 'WAIT FOR FALLING EDGE'
218 # This seems to be a reset slot, wait for its end.
219 self.state = 'WAIT FOR RISING EDGE'
220 elif self.state == 'WAIT FOR RISING EDGE':
221 # The end of a cycle is a rising edge.
223 # Check if this was a reset cycle.
224 t = self.samplenum - self.fall
225 if t > self.cnt_normal_reset:
226 # Save the sample number for the falling edge.
227 self.rise = self.samplenum
228 self.state = 'WAIT FOR PRESENCE DETECT'
229 # Exit overdrive mode.
231 self.put(self.fall, self.cnt_bit[self.overdrive],
232 self.out_ann, [0, ['EXIT 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]:
255 self.put(self.fall, self.samplenum, self.out_ann,
256 [0, ['RESET/PRESENCE: %s'
257 % ('False' if self.present else 'True')]])
258 self.put(self.fall, self.samplenum, self.out_proto,
259 ['RESET/PRESENCE', not self.present])
260 # Wait for next slot.
261 self.state = 'WAIT FOR FALLING EDGE'
263 # This seems to be a reset slot, wait for its end.
264 self.state = 'WAIT FOR RISING EDGE'
266 raise Exception('Invalid state: %s' % self.state)