]>
Commit | Line | Data |
---|---|---|
1 | ## | |
2 | ## This file is part of the sigrok project. | |
3 | ## | |
4 | ## Copyright (C) 2012 Iztok Jeras <iztok.jeras@gmail.com> | |
5 | ## | |
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. | |
10 | ## | |
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. | |
15 | ## | |
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 | |
19 | ## | |
20 | ||
21 | # 1-Wire protocol decoder (link layer) | |
22 | ||
23 | import sigrokdecode as srd | |
24 | ||
25 | class Decoder(srd.Decoder): | |
26 | api_version = 1 | |
27 | id = 'onewire_link' | |
28 | name = '1-Wire link layer' | |
29 | longname = '1-Wire serial communication bus (link layer)' | |
30 | desc = 'Bidirectional, half-duplex, asynchronous serial bus.' | |
31 | license = 'gplv2+' | |
32 | inputs = ['logic'] | |
33 | outputs = ['onewire_link'] | |
34 | probes = [ | |
35 | {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire signal line'}, | |
36 | ] | |
37 | optional_probes = [ | |
38 | {'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power supply pin'}, | |
39 | ] | |
40 | options = { | |
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], | |
51 | } | |
52 | annotations = [ | |
53 | ['Text', 'Human-readable text'], | |
54 | ['Warnings', 'Human-readable warnings'], | |
55 | ] | |
56 | ||
57 | def __init__(self, **kwargs): | |
58 | self.samplenum = 0 | |
59 | self.state = 'WAIT FOR FALLING EDGE' | |
60 | self.present = 0 | |
61 | self.bit = 0 | |
62 | self.bit_cnt = 0 | |
63 | self.command = 0 | |
64 | self.overdrive = 0 | |
65 | self.fall = 0 | |
66 | self.rise = 0 | |
67 | ||
68 | def start(self, metadata): | |
69 | self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire_link') | |
70 | self.out_ann = self.add(srd.OUTPUT_ANN, 'onewire_link') | |
71 | ||
72 | self.samplerate = metadata['samplerate'] | |
73 | ||
74 | # Check if samplerate is appropriate. | |
75 | if self.options['overdrive']: | |
76 | if self.samplerate < 2000000: | |
77 | self.put(0, 0, self.out_ann, [1, | |
78 | ['ERROR: Sampling rate is too low. Must be above 2MHz ' + | |
79 | 'for proper overdrive mode decoding.']]) | |
80 | elif self.samplerate < 5000000: | |
81 | self.put(0, 0, self.out_ann, [1, | |
82 | ['WARNING: Sampling rate is suggested to be above 5MHz ' + | |
83 | 'for proper overdrive mode decoding.']]) | |
84 | else: | |
85 | if self.samplerate < 400000: | |
86 | self.put(0, 0, self.out_ann, [1, | |
87 | ['ERROR: Sampling rate is too low. Must be above ' + | |
88 | '400kHz for proper normal mode decoding.']]) | |
89 | elif (self.samplerate < 1000000): | |
90 | self.put(0, 0, self.out_ann, [1, | |
91 | ['WARNING: Sampling rate is suggested to be above ' + | |
92 | '1MHz for proper normal mode decoding.']]) | |
93 | ||
94 | # The default 1-Wire time base is 30us. This is used to calculate | |
95 | # sampling times. | |
96 | samplerate = float(self.samplerate) | |
97 | if self.options['cnt_normal_bit']: | |
98 | self.cnt_normal_bit = self.options['cnt_normal_bit'] | |
99 | else: | |
100 | self.cnt_normal_bit = int(samplerate * 0.000015) - 1 # 15ns | |
101 | if self.options['cnt_normal_slot']: | |
102 | self.cnt_normal_slot = self.options['cnt_normal_slot'] | |
103 | else: | |
104 | self.cnt_normal_slot = int(samplerate * 0.000060) - 1 # 60ns | |
105 | if self.options['cnt_normal_presence']: | |
106 | self.cnt_normal_presence = self.options['cnt_normal_presence'] | |
107 | else: | |
108 | self.cnt_normal_presence = int(samplerate * 0.000075) - 1 # 75ns | |
109 | if self.options['cnt_normal_reset']: | |
110 | self.cnt_normal_reset = self.options['cnt_normal_reset'] | |
111 | else: | |
112 | self.cnt_normal_reset = int(samplerate * 0.000480) - 1 # 480ns | |
113 | if self.options['cnt_overdrive_bit']: | |
114 | self.cnt_overdrive_bit = self.options['cnt_overdrive_bit'] | |
115 | else: | |
116 | self.cnt_overdrive_bit = int(samplerate * 0.000002) - 1 # 2ns | |
117 | if self.options['cnt_overdrive_slot']: | |
118 | self.cnt_overdrive_slot = self.options['cnt_overdrive_slot'] | |
119 | else: | |
120 | self.cnt_overdrive_slot = int(samplerate * 0.0000073) - 1 # 6ns+1.3ns | |
121 | if self.options['cnt_overdrive_presence']: | |
122 | self.cnt_overdrive_presence = self.options['cnt_overdrive_presence'] | |
123 | else: | |
124 | self.cnt_overdrive_presence = int(samplerate * 0.000010) - 1 # 10ns | |
125 | if self.options['cnt_overdrive_reset']: | |
126 | self.cnt_overdrive_reset = self.options['cnt_overdrive_reset'] | |
127 | else: | |
128 | self.cnt_overdrive_reset = int(samplerate * 0.000048) - 1 # 48ns | |
129 | ||
130 | # Organize values into lists. | |
131 | self.cnt_bit = [self.cnt_normal_bit, self.cnt_overdrive_bit] | |
132 | self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence] | |
133 | self.cnt_reset = [self.cnt_normal_reset, self.cnt_overdrive_reset] | |
134 | self.cnt_slot = [self.cnt_normal_slot, self.cnt_overdrive_slot] | |
135 | ||
136 | # Check if sample times are in the allowed range. | |
137 | ||
138 | time_min = float(self.cnt_normal_bit) / self.samplerate | |
139 | time_max = float(self.cnt_normal_bit + 1) / self.samplerate | |
140 | if (time_min < 0.000005) or (time_max > 0.000015): | |
141 | self.put(0, 0, self.out_ann, [1, | |
142 | ['WARNING: The normal mode data sample time interval ' + | |
143 | '(%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).' | |
144 | % (time_min * 1000000, time_max * 1000000)]]) | |
145 | ||
146 | time_min = float(self.cnt_normal_presence) / self.samplerate | |
147 | time_max = float(self.cnt_normal_presence + 1) / self.samplerate | |
148 | if (time_min < 0.0000681) or (time_max > 0.000075): | |
149 | self.put(0, 0, self.out_ann, [1, | |
150 | ['WARNING: The normal mode presence sample time interval ' + | |
151 | '(%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).' | |
152 | % (time_min * 1000000, time_max * 1000000)]]) | |
153 | ||
154 | time_min = float(self.cnt_overdrive_bit) / self.samplerate | |
155 | time_max = float(self.cnt_overdrive_bit + 1) / self.samplerate | |
156 | if (time_min < 0.000001) or (time_max > 0.000002): | |
157 | self.put(0, 0, self.out_ann, [1, | |
158 | ['WARNING: The overdrive mode data sample time interval ' + | |
159 | '(%2.1fus-%2.1fus) should be inside (1.0us, 2.0us).' | |
160 | % (time_min * 1000000, time_max * 1000000)]]) | |
161 | ||
162 | time_min = float(self.cnt_overdrive_presence) / self.samplerate | |
163 | time_max = float(self.cnt_overdrive_presence + 1) / self.samplerate | |
164 | if (time_min < 0.0000073) or (time_max > 0.000010): | |
165 | self.put(0, 0, self.out_ann, [1, | |
166 | ['WARNING: The overdrive mode presence sample time interval ' + | |
167 | '(%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).' | |
168 | % (time_min*1000000, time_max*1000000)]]) | |
169 | ||
170 | def report(self): | |
171 | pass | |
172 | ||
173 | def decode(self, ss, es, data): | |
174 | for (self.samplenum, (owr, pwr)) in data: | |
175 | # State machine. | |
176 | if self.state == 'WAIT FOR FALLING EDGE': | |
177 | # The start of a cycle is a falling edge. | |
178 | if owr != 0: | |
179 | continue | |
180 | # Save the sample number for the falling edge. | |
181 | self.fall = self.samplenum | |
182 | # Go to waiting for sample time. | |
183 | self.state = 'WAIT FOR DATA SAMPLE' | |
184 | elif self.state == 'WAIT FOR DATA SAMPLE': | |
185 | # Sample data bit. | |
186 | t = self.samplenum - self.fall | |
187 | if t == self.cnt_bit[self.overdrive]: | |
188 | self.bit = owr | |
189 | self.state = 'WAIT FOR DATA SLOT END' | |
190 | elif self.state == 'WAIT FOR DATA SLOT END': | |
191 | # A data slot ends in a recovery period, otherwise, this is | |
192 | # probably a reset. | |
193 | t = self.samplenum - self.fall | |
194 | if t != self.cnt_slot[self.overdrive]: | |
195 | continue | |
196 | ||
197 | if owr == 0: | |
198 | # This seems to be a reset slot, wait for its end. | |
199 | self.state = 'WAIT FOR RISING EDGE' | |
200 | continue | |
201 | ||
202 | self.put(self.fall, self.samplenum, self.out_ann, | |
203 | [0, ['Bit: %d' % self.bit]]) | |
204 | self.put(self.fall, self.samplenum, self.out_proto, | |
205 | ['BIT', self.bit]) | |
206 | ||
207 | # Checking the first command to see if overdrive mode | |
208 | # should be entered. | |
209 | if self.bit_cnt <= 8: | |
210 | self.command |= (self.bit << self.bit_cnt) | |
211 | elif self.bit_cnt == 8 and self.command in [0x3c, 0x69]: | |
212 | self.put(self.fall, self.cnt_bit[self.overdrive], | |
213 | self.out_ann, [0, ['Entering overdrive mode']]) | |
214 | # Increment the bit counter. | |
215 | self.bit_cnt += 1 | |
216 | # Wait for next slot. | |
217 | self.state = 'WAIT FOR FALLING EDGE' | |
218 | elif self.state == 'WAIT FOR RISING EDGE': | |
219 | # The end of a cycle is a rising edge. | |
220 | if owr != 1: | |
221 | continue | |
222 | ||
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. | |
230 | if self.overdrive: | |
231 | self.put(self.fall, self.cnt_bit[self.overdrive], | |
232 | self.out_ann, [0, ['Exiting overdrive mode']]) | |
233 | self.overdrive = 0 | |
234 | # Clear command bit counter and data register. | |
235 | self.bit_cnt = 0 | |
236 | self.command = 0 | |
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. | |
242 | else: | |
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]: | |
248 | self.present = owr | |
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]: | |
254 | continue | |
255 | ||
256 | if owr == 0: | |
257 | # This seems to be a reset slot, wait for its end. | |
258 | self.state = 'WAIT FOR RISING EDGE' | |
259 | continue | |
260 | ||
261 | self.put(self.fall, self.samplenum, self.out_ann, | |
262 | [0, ['Reset/presence: %s' | |
263 | % ('false' if self.present else 'true')]]) | |
264 | self.put(self.fall, self.samplenum, self.out_proto, | |
265 | ['RESET/PRESENCE', not self.present]) | |
266 | # Wait for next slot. | |
267 | self.state = 'WAIT FOR FALLING EDGE' | |
268 | else: | |
269 | raise Exception('Invalid state: %s' % self.state) |