2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2014 Johannes Roemer <jroemer@physik.uni-wuerzburg.de>
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, see <http://www.gnu.org/licenses/>.
20 import sigrokdecode as srd
22 # Define valid timing values (in microseconds).
24 'START LOW' : {'min': 750, 'max': 25000},
25 'START HIGH' : {'min': 10, 'max': 10000},
26 'RESPONSE LOW' : {'min': 50, 'max': 90},
27 'RESPONSE HIGH' : {'min': 50, 'max': 90},
28 'BIT LOW' : {'min': 45, 'max': 90},
29 'BIT 0 HIGH' : {'min': 20, 'max': 35},
30 'BIT 1 HIGH' : {'min': 65, 'max': 80},
33 class SamplerateError(Exception):
36 class Decoder(srd.Decoder):
40 longname = 'Aosong AM230x/DHTxx/RHTxx'
41 desc = 'Aosong AM230x/DHTxx/RHTxx humidity/temperature sensor.'
45 tags = ['IC', 'Sensor']
47 {'id': 'sda', 'name': 'SDA', 'desc': 'Single wire serial data line'},
50 {'id': 'device', 'desc': 'Device type',
51 'default': 'am230x', 'values': ('am230x/rht', 'dht11')},
55 ('response', 'Response'),
59 ('humidity', 'Relative humidity'),
60 ('temperature', 'Temperature'),
61 ('checksum', 'Checksum'),
64 ('bits', 'Bits', (0, 1, 2, 3)),
65 ('bytes', 'Bytes', (4,)),
66 ('results', 'Results', (5, 6, 7)),
69 def putfs(self, data):
70 self.put(self.fall, self.samplenum, self.out_ann, data)
73 self.put(self.bytepos[-1], self.samplenum, self.out_ann, data)
76 self.put(self.bytepos[-2], self.samplenum, self.out_ann, data)
78 def reset_variables(self):
79 self.state = 'WAIT FOR START LOW'
85 def is_valid(self, name):
87 if name.endswith('LOW'):
88 dt = self.samplenum - self.fall
89 elif name.endswith('HIGH'):
90 dt = self.samplenum - self.rise
91 if dt >= self.cnt[name]['min'] and dt <= self.cnt[name]['max']:
95 def bits2num(self, bitlist):
97 for i in range(len(bitlist)):
98 number += bitlist[-1 - i] * 2**i
101 def calculate_humidity(self, bitlist):
103 if self.options['device'] == 'dht11':
104 h = self.bits2num(bitlist[0:8])
106 h = self.bits2num(bitlist) / 10
109 def calculate_temperature(self, bitlist):
111 if self.options['device'] == 'dht11':
112 t = self.bits2num(bitlist[0:8])
114 t = self.bits2num(bitlist[1:]) / 10
119 def calculate_checksum(self, bitlist):
121 for i in range(8, len(bitlist) + 1, 8):
122 checksum += self.bits2num(bitlist[i-8:i])
123 return checksum % 256
129 self.samplerate = None
130 self.reset_variables()
133 self.out_ann = self.register(srd.OUTPUT_ANN)
135 def metadata(self, key, value):
136 if key != srd.SRD_CONF_SAMPLERATE:
138 self.samplerate = value
139 # Convert microseconds to sample counts.
144 self.cnt[e][t] = timing[e][t] * self.samplerate / 1000000
146 def handle_byte(self, bit):
147 self.bits.append(bit)
148 self.putfs([2, ['Bit: %d' % bit, '%d' % bit]])
149 self.fall = self.samplenum
150 self.state = 'WAIT FOR BIT HIGH'
151 if len(self.bits) % 8 == 0:
152 byte = self.bits2num(self.bits[-8:])
153 self.putb([4, ['Byte: %#04x' % byte, '%#04x' % byte]])
154 if len(self.bits) == 16:
155 h = self.calculate_humidity(self.bits[-16:])
156 self.putv([5, ['Humidity: %.1f %%' % h, 'RH = %.1f %%' % h]])
157 elif len(self.bits) == 32:
158 t = self.calculate_temperature(self.bits[-16:])
159 self.putv([6, ['Temperature: %.1f °C' % t, 'T = %.1f °C' % t]])
160 elif len(self.bits) == 40:
161 parity = self.bits2num(self.bits[-8:])
162 if parity == self.calculate_checksum(self.bits[0:32]):
163 self.putb([7, ['Checksum: OK', 'OK']])
165 self.putb([7, ['Checksum: not OK', 'NOK']])
166 self.state = 'WAIT FOR END'
167 self.bytepos.append(self.samplenum)
170 if not self.samplerate:
171 raise SamplerateError('Cannot decode without samplerate.')
174 if self.state == 'WAIT FOR START LOW':
176 self.fall = self.samplenum
177 self.state = 'WAIT FOR START HIGH'
178 elif self.state == 'WAIT FOR START HIGH':
180 if self.is_valid('START LOW'):
181 self.rise = self.samplenum
182 self.state = 'WAIT FOR RESPONSE LOW'
184 self.reset_variables()
185 elif self.state == 'WAIT FOR RESPONSE LOW':
187 if self.is_valid('START HIGH'):
188 self.putfs([0, ['Start', 'S']])
189 self.fall = self.samplenum
190 self.state = 'WAIT FOR RESPONSE HIGH'
192 self.reset_variables()
193 elif self.state == 'WAIT FOR RESPONSE HIGH':
195 if self.is_valid('RESPONSE LOW'):
196 self.rise = self.samplenum
197 self.state = 'WAIT FOR FIRST BIT'
199 self.reset_variables()
200 elif self.state == 'WAIT FOR FIRST BIT':
202 if self.is_valid('RESPONSE HIGH'):
203 self.putfs([1, ['Response', 'R']])
204 self.fall = self.samplenum
205 self.bytepos.append(self.samplenum)
206 self.state = 'WAIT FOR BIT HIGH'
208 self.reset_variables()
209 elif self.state == 'WAIT FOR BIT HIGH':
211 if self.is_valid('BIT LOW'):
212 self.rise = self.samplenum
213 self.state = 'WAIT FOR BIT LOW'
215 self.reset_variables()
216 elif self.state == 'WAIT FOR BIT LOW':
218 if self.is_valid('BIT 0 HIGH'):
220 elif self.is_valid('BIT 1 HIGH'):
223 self.reset_variables()
225 self.handle_byte(bit)
226 elif self.state == 'WAIT FOR END':
228 self.putfs([3, ['End', 'E']])
229 self.reset_variables()