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all decoders: introduce a reset() method
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1##
2## This file is part of the libsigrokdecode project.
3##
4## Copyright (C) 2014 Johannes Roemer <jroemer@physik.uni-wuerzburg.de>
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
4539e9ca 17## along with this program; if not, see <http://www.gnu.org/licenses/>.
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18##
19
20import sigrokdecode as srd
21
22# Define valid timing values (in microseconds).
23timing = {
24 'START LOW' : {'min': 750, 'max': 25000},
25 'START HIGH' : {'min': 10, 'max': 10000},
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26 'RESPONSE LOW' : {'min': 50, 'max': 90},
27 'RESPONSE HIGH' : {'min': 50, 'max': 90},
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28 'BIT LOW' : {'min': 45, 'max': 90},
29 'BIT 0 HIGH' : {'min': 20, 'max': 35},
30 'BIT 1 HIGH' : {'min': 65, 'max': 80},
31}
32
33class SamplerateError(Exception):
34 pass
35
36class Decoder(srd.Decoder):
b6bac00c 37 api_version = 3
b1f2b85b 38 id = 'am230x'
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39 name = 'AM230x/DHTxx/RHTxx'
40 longname = 'Aosong AM230x/DHTxx/RHTxx'
41 desc = 'Aosong AM230x/DHTxx/RHTxx humidity/temperature sensor protocol.'
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42 license = 'gplv2+'
43 inputs = ['logic']
44 outputs = ['am230x']
45 channels = (
46 {'id': 'sda', 'name': 'SDA', 'desc': 'Single wire serial data line'},
47 )
48 options = (
cda1352a 49 {'id': 'device', 'desc': 'Device type',
e2ba53bb 50 'default': 'am230x', 'values': ('am230x/rht', 'dht11')},
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51 )
52 annotations = (
53 ('start', 'Start'),
54 ('response', 'Response'),
55 ('bit', 'Bit'),
56 ('end', 'End'),
57 ('byte', 'Byte'),
58 ('humidity', 'Relative humidity in percent'),
59 ('temperature', 'Temperature in degrees Celsius'),
60 ('checksum', 'Checksum'),
61 )
62 annotation_rows = (
63 ('bits', 'Bits', (0, 1, 2, 3)),
64 ('bytes', 'Bytes', (4,)),
65 ('results', 'Results', (5, 6, 7)),
66 )
67
68 def putfs(self, data):
69 self.put(self.fall, self.samplenum, self.out_ann, data)
70
71 def putb(self, data):
72 self.put(self.bytepos[-1], self.samplenum, self.out_ann, data)
73
74 def putv(self, data):
75 self.put(self.bytepos[-2], self.samplenum, self.out_ann, data)
76
779c540d 77 def reset_variables(self):
b1f2b85b 78 self.state = 'WAIT FOR START LOW'
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79 self.fall = 0
80 self.rise = 0
81 self.bits = []
82 self.bytepos = []
83
84 def is_valid(self, name):
85 dt = 0
86 if name.endswith('LOW'):
87 dt = self.samplenum - self.fall
88 elif name.endswith('HIGH'):
89 dt = self.samplenum - self.rise
90 if dt >= self.cnt[name]['min'] and dt <= self.cnt[name]['max']:
91 return True
92 return False
93
94 def bits2num(self, bitlist):
95 number = 0
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96 for i in range(len(bitlist)):
97 number += bitlist[-1 - i] * 2**i
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98 return number
99
100 def calculate_humidity(self, bitlist):
101 h = 0
cda1352a 102 if self.options['device'] == 'dht11':
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103 h = self.bits2num(bitlist[0:8])
104 else:
105 h = self.bits2num(bitlist) / 10
106 return h
107
108 def calculate_temperature(self, bitlist):
109 t = 0
cda1352a 110 if self.options['device'] == 'dht11':
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111 t = self.bits2num(bitlist[0:8])
112 else:
113 t = self.bits2num(bitlist[1:]) / 10
114 if bitlist[0] == 1:
115 t = -t
116 return t
117
118 def calculate_checksum(self, bitlist):
119 checksum = 0
47405f47 120 for i in range(8, len(bitlist) + 1, 8):
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121 checksum += self.bits2num(bitlist[i-8:i])
122 return checksum % 256
123
92b7b49f 124 def __init__(self):
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125 self.reset()
126
127 def reset(self):
b1f2b85b 128 self.samplerate = None
779c540d 129 self.reset_variables()
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130
131 def start(self):
132 self.out_ann = self.register(srd.OUTPUT_ANN)
133
134 def metadata(self, key, value):
135 if key != srd.SRD_CONF_SAMPLERATE:
136 return
137 self.samplerate = value
138 # Convert microseconds to sample counts.
139 self.cnt = {}
140 for e in timing:
141 self.cnt[e] = {}
142 for t in timing[e]:
143 self.cnt[e][t] = timing[e][t] * self.samplerate / 1000000
144
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145 def handle_byte(self, bit):
146 self.bits.append(bit)
147 self.putfs([2, ['Bit: %d' % bit, '%d' % bit]])
148 self.fall = self.samplenum
149 self.state = 'WAIT FOR BIT HIGH'
150 if len(self.bits) % 8 == 0:
151 byte = self.bits2num(self.bits[-8:])
152 self.putb([4, ['Byte: %#04x' % byte, '%#04x' % byte]])
153 if len(self.bits) == 16:
154 h = self.calculate_humidity(self.bits[-16:])
155 self.putv([5, ['Humidity: %.1f %%' % h, 'RH = %.1f %%' % h]])
156 elif len(self.bits) == 32:
157 t = self.calculate_temperature(self.bits[-16:])
158 self.putv([6, ['Temperature: %.1f °C' % t, 'T = %.1f °C' % t]])
159 elif len(self.bits) == 40:
160 parity = self.bits2num(self.bits[-8:])
161 if parity == self.calculate_checksum(self.bits[0:32]):
162 self.putb([7, ['Checksum: OK', 'OK']])
163 else:
164 self.putb([7, ['Checksum: not OK', 'NOK']])
165 self.state = 'WAIT FOR END'
166 self.bytepos.append(self.samplenum)
167
b6bac00c 168 def decode(self):
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169 if not self.samplerate:
170 raise SamplerateError('Cannot decode without samplerate.')
b6bac00c 171 while True:
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172 # State machine.
173 if self.state == 'WAIT FOR START LOW':
b6bac00c 174 self.wait({0: 'f'})
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175 self.fall = self.samplenum
176 self.state = 'WAIT FOR START HIGH'
177 elif self.state == 'WAIT FOR START HIGH':
b6bac00c 178 self.wait({0: 'r'})
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179 if self.is_valid('START LOW'):
180 self.rise = self.samplenum
181 self.state = 'WAIT FOR RESPONSE LOW'
182 else:
779c540d 183 self.reset_variables()
b1f2b85b 184 elif self.state == 'WAIT FOR RESPONSE LOW':
b6bac00c 185 self.wait({0: 'f'})
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186 if self.is_valid('START HIGH'):
187 self.putfs([0, ['Start', 'S']])
188 self.fall = self.samplenum
189 self.state = 'WAIT FOR RESPONSE HIGH'
190 else:
779c540d 191 self.reset_variables()
b1f2b85b 192 elif self.state == 'WAIT FOR RESPONSE HIGH':
b6bac00c 193 self.wait({0: 'r'})
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194 if self.is_valid('RESPONSE LOW'):
195 self.rise = self.samplenum
196 self.state = 'WAIT FOR FIRST BIT'
197 else:
779c540d 198 self.reset_variables()
b1f2b85b 199 elif self.state == 'WAIT FOR FIRST BIT':
b6bac00c 200 self.wait({0: 'f'})
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201 if self.is_valid('RESPONSE HIGH'):
202 self.putfs([1, ['Response', 'R']])
203 self.fall = self.samplenum
204 self.bytepos.append(self.samplenum)
205 self.state = 'WAIT FOR BIT HIGH'
206 else:
779c540d 207 self.reset_variables()
b1f2b85b 208 elif self.state == 'WAIT FOR BIT HIGH':
b6bac00c 209 self.wait({0: 'r'})
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210 if self.is_valid('BIT LOW'):
211 self.rise = self.samplenum
212 self.state = 'WAIT FOR BIT LOW'
213 else:
779c540d 214 self.reset_variables()
b1f2b85b 215 elif self.state == 'WAIT FOR BIT LOW':
b6bac00c 216 self.wait({0: 'f'})
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217 if self.is_valid('BIT 0 HIGH'):
218 bit = 0
219 elif self.is_valid('BIT 1 HIGH'):
220 bit = 1
221 else:
779c540d 222 self.reset_variables()
b1f2b85b 223 continue
0b6bc7f9 224 self.handle_byte(bit)
b1f2b85b 225 elif self.state == 'WAIT FOR END':
b6bac00c 226 self.wait({0: 'r'})
b1f2b85b 227 self.putfs([3, ['End', 'E']])
779c540d 228 self.reset_variables()