1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2014 Johannes Roemer <jroemer@physik.uni-wuerzburg.de>
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, see <http://www.gnu.org/licenses/>.
##
import sigrokdecode as srd
# Define valid timing values (in microseconds).
timing = {
'START LOW' : {'min': 750, 'max': 25000},
'START HIGH' : {'min': 10, 'max': 10000},
'RESPONSE LOW' : {'min': 50, 'max': 90},
'RESPONSE HIGH' : {'min': 50, 'max': 90},
'BIT LOW' : {'min': 45, 'max': 90},
'BIT 0 HIGH' : {'min': 20, 'max': 35},
'BIT 1 HIGH' : {'min': 65, 'max': 80},
}
class SamplerateError(Exception):
pass
class Decoder(srd.Decoder):
api_version = 3
id = 'am230x'
name = 'AM230x/DHTxx/RHTxx'
longname = 'Aosong AM230x/DHTxx/RHTxx'
desc = 'Aosong AM230x/DHTxx/RHTxx humidity/temperature sensor protocol.'
license = 'gplv2+'
inputs = ['logic']
outputs = ['am230x']
channels = (
{'id': 'sda', 'name': 'SDA', 'desc': 'Single wire serial data line'},
)
options = (
{'id': 'device', 'desc': 'Device type',
'default': 'am230x', 'values': ('am230x/rht', 'dht11')},
)
annotations = (
('start', 'Start'),
('response', 'Response'),
('bit', 'Bit'),
('end', 'End'),
('byte', 'Byte'),
('humidity', 'Relative humidity in percent'),
('temperature', 'Temperature in degrees Celsius'),
('checksum', 'Checksum'),
)
annotation_rows = (
('bits', 'Bits', (0, 1, 2, 3)),
('bytes', 'Bytes', (4,)),
('results', 'Results', (5, 6, 7)),
)
def putfs(self, data):
self.put(self.fall, self.samplenum, self.out_ann, data)
def putb(self, data):
self.put(self.bytepos[-1], self.samplenum, self.out_ann, data)
def putv(self, data):
self.put(self.bytepos[-2], self.samplenum, self.out_ann, data)
def reset_variables(self):
self.state = 'WAIT FOR START LOW'
self.fall = 0
self.rise = 0
self.bits = []
self.bytepos = []
def is_valid(self, name):
dt = 0
if name.endswith('LOW'):
dt = self.samplenum - self.fall
elif name.endswith('HIGH'):
dt = self.samplenum - self.rise
if dt >= self.cnt[name]['min'] and dt <= self.cnt[name]['max']:
return True
return False
def bits2num(self, bitlist):
number = 0
for i in range(len(bitlist)):
number += bitlist[-1 - i] * 2**i
return number
def calculate_humidity(self, bitlist):
h = 0
if self.options['device'] == 'dht11':
h = self.bits2num(bitlist[0:8])
else:
h = self.bits2num(bitlist) / 10
return h
def calculate_temperature(self, bitlist):
t = 0
if self.options['device'] == 'dht11':
t = self.bits2num(bitlist[0:8])
else:
t = self.bits2num(bitlist[1:]) / 10
if bitlist[0] == 1:
t = -t
return t
def calculate_checksum(self, bitlist):
checksum = 0
for i in range(8, len(bitlist) + 1, 8):
checksum += self.bits2num(bitlist[i-8:i])
return checksum % 256
def __init__(self):
self.reset()
def reset(self):
self.samplerate = None
self.reset_variables()
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
def metadata(self, key, value):
if key != srd.SRD_CONF_SAMPLERATE:
return
self.samplerate = value
# Convert microseconds to sample counts.
self.cnt = {}
for e in timing:
self.cnt[e] = {}
for t in timing[e]:
self.cnt[e][t] = timing[e][t] * self.samplerate / 1000000
def handle_byte(self, bit):
self.bits.append(bit)
self.putfs([2, ['Bit: %d' % bit, '%d' % bit]])
self.fall = self.samplenum
self.state = 'WAIT FOR BIT HIGH'
if len(self.bits) % 8 == 0:
byte = self.bits2num(self.bits[-8:])
self.putb([4, ['Byte: %#04x' % byte, '%#04x' % byte]])
if len(self.bits) == 16:
h = self.calculate_humidity(self.bits[-16:])
self.putv([5, ['Humidity: %.1f %%' % h, 'RH = %.1f %%' % h]])
elif len(self.bits) == 32:
t = self.calculate_temperature(self.bits[-16:])
self.putv([6, ['Temperature: %.1f °C' % t, 'T = %.1f °C' % t]])
elif len(self.bits) == 40:
parity = self.bits2num(self.bits[-8:])
if parity == self.calculate_checksum(self.bits[0:32]):
self.putb([7, ['Checksum: OK', 'OK']])
else:
self.putb([7, ['Checksum: not OK', 'NOK']])
self.state = 'WAIT FOR END'
self.bytepos.append(self.samplenum)
def decode(self):
if not self.samplerate:
raise SamplerateError('Cannot decode without samplerate.')
while True:
# State machine.
if self.state == 'WAIT FOR START LOW':
self.wait({0: 'f'})
self.fall = self.samplenum
self.state = 'WAIT FOR START HIGH'
elif self.state == 'WAIT FOR START HIGH':
self.wait({0: 'r'})
if self.is_valid('START LOW'):
self.rise = self.samplenum
self.state = 'WAIT FOR RESPONSE LOW'
else:
self.reset_variables()
elif self.state == 'WAIT FOR RESPONSE LOW':
self.wait({0: 'f'})
if self.is_valid('START HIGH'):
self.putfs([0, ['Start', 'S']])
self.fall = self.samplenum
self.state = 'WAIT FOR RESPONSE HIGH'
else:
self.reset_variables()
elif self.state == 'WAIT FOR RESPONSE HIGH':
self.wait({0: 'r'})
if self.is_valid('RESPONSE LOW'):
self.rise = self.samplenum
self.state = 'WAIT FOR FIRST BIT'
else:
self.reset_variables()
elif self.state == 'WAIT FOR FIRST BIT':
self.wait({0: 'f'})
if self.is_valid('RESPONSE HIGH'):
self.putfs([1, ['Response', 'R']])
self.fall = self.samplenum
self.bytepos.append(self.samplenum)
self.state = 'WAIT FOR BIT HIGH'
else:
self.reset_variables()
elif self.state == 'WAIT FOR BIT HIGH':
self.wait({0: 'r'})
if self.is_valid('BIT LOW'):
self.rise = self.samplenum
self.state = 'WAIT FOR BIT LOW'
else:
self.reset_variables()
elif self.state == 'WAIT FOR BIT LOW':
self.wait({0: 'f'})
if self.is_valid('BIT 0 HIGH'):
bit = 0
elif self.is_valid('BIT 1 HIGH'):
bit = 1
else:
self.reset_variables()
continue
self.handle_byte(bit)
elif self.state == 'WAIT FOR END':
self.wait({0: 'r'})
self.putfs([3, ['End', 'E']])
self.reset_variables()
|
