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
|
##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.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, write to the Free Software
## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
##
# TODO: Better support for various LM75 compatible devices.
import sigrokdecode as srd
# LM75 only supports 9 bit resolution, compatible devices usually 9-12 bits.
resolution = {
# CONFIG[6:5]: <resolution>
0x00: 9,
0x01: 10,
0x02: 11,
0x03: 12,
}
ft = {
# CONFIG[4:3]: <fault tolerance setting>
0x00: 1,
0x01: 2,
0x02: 4,
0x03: 6,
}
class Decoder(srd.Decoder):
api_version = 2
id = 'lm75'
name = 'LM75'
longname = 'National LM75'
desc = 'National LM75 (and compatibles) temperature sensor.'
license = 'gplv2+'
inputs = ['i2c']
outputs = ['lm75']
options = (
{'id': 'sensor', 'desc': 'Sensor type', 'default': 'lm75',
'values': ('lm75',)},
{'id': 'resolution', 'desc': 'Resolution (bits)', 'default': 9,
'values': (9, 10, 11, 12)},
)
annotations = (
('celsius', 'Temperature in degrees Celsius'),
('kelvin', 'Temperature in Kelvin'),
('text-verbose', 'Human-readable text (verbose)'),
('text', 'Human-readable text'),
('warnings', 'Human-readable warnings'),
)
def __init__(self, **kwargs):
self.state = 'IDLE'
self.reg = 0x00 # Currently selected register
self.databytes = []
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
def putx(self, data):
# Helper for annotations which span exactly one I²C packet.
self.put(self.ss, self.es, self.out_ann, data)
def putb(self, data):
# Helper for annotations which span a block of I²C packets.
self.put(self.block_start, self.block_end, self.out_ann, data)
def warn_upon_invalid_slave(self, addr):
# LM75 and compatible devices have a 7-bit I²C slave address where
# the 4 MSBs are fixed to 1001, and the 3 LSBs are configurable.
# Thus, valid slave addresses (1001xxx) range from 0x48 to 0x4f.
if addr not in range(0x48, 0x4f + 1):
s = 'Warning: I²C slave 0x%02x not an LM75 compatible sensor.'
self.putx([4, [s % addr]])
def output_temperature(self, s, rw):
# TODO: Support for resolutions other than 9 bit.
before, after = self.databytes[0], (self.databytes[1] >> 7) * 5
celsius = float('%d.%d' % (before, after))
kelvin = celsius + 273.15
self.putb([0, ['%s: %.1f °C' % (s, celsius)]])
self.putb([1, ['%s: %.1f K' % (s, kelvin)]])
# Warn about the temperature register (0x00) being read-only.
if s == 'Temperature' and rw == 'WRITE':
s = 'Warning: The temperature register is read-only!'
self.putb([4, [s]])
def handle_temperature_reg(self, b, s, rw):
# Common helper for the temperature/T_HYST/T_OS registers.
if len(self.databytes) == 0:
self.block_start = self.ss
self.databytes.append(b)
return
self.databytes.append(b)
self.block_end = self.es
self.output_temperature(s, rw)
self.databytes = []
def handle_reg_0x00(self, b, rw):
# Temperature register (16bits, read-only).
self.handle_temperature_reg(b, 'Temperature', rw)
def handle_reg_0x01(self, b, rw):
# Configuration register (8 bits, read/write).
# TODO: Bit-exact annotation ranges.
sd = b & (1 << 0)
tmp = 'normal operation' if (sd == 0) else 'shutdown mode'
s = 'SD = %d: %s\n' % (sd, tmp)
s2 = 'SD = %s, ' % tmp
cmp_int = b & (1 << 1)
tmp = 'comparator' if (cmp_int == 0) else 'interrupt'
s += 'CMP/INT = %d: %s mode\n' % (cmp_int, tmp)
s2 += 'CMP/INT = %s, ' % tmp
pol = b & (1 << 2)
tmp = 'low' if (pol == 0) else 'high'
s += 'POL = %d: OS polarity is active-%s\n' % (pol, tmp)
s2 += 'POL = active-%s, ' % tmp
bits = (b & ((1 << 4) | (1 << 3))) >> 3
s += 'Fault tolerance setting: %d bit(s)\n' % ft[bits]
s2 += 'FT = %d' % ft[bits]
# Not supported by LM75, but by various compatible devices.
if self.options['sensor'] != 'lm75': # TODO
bits = (b & ((1 << 6) | (1 << 5))) >> 5
s += 'Resolution: %d bits\n' % resolution[bits]
s2 += ', resolution = %d' % resolution[bits]
self.putx([2, [s]])
self.putx([3, [s2]])
def handle_reg_0x02(self, b, rw):
# T_HYST register (16 bits, read/write).
self.handle_temperature_reg(b, 'T_HYST trip temperature', rw)
def handle_reg_0x03(self, b, rw):
# T_OS register (16 bits, read/write).
self.handle_temperature_reg(b, 'T_OS trip temperature', rw)
def decode(self, ss, es, data):
cmd, databyte = data
# Store the start/end samples of this I²C packet.
self.ss, self.es = ss, es
# State machine.
if self.state == 'IDLE':
# Wait for an I²C START condition.
if cmd != 'START':
return
self.state = 'GET SLAVE ADDR'
elif self.state == 'GET SLAVE ADDR':
# Wait for an address read/write operation.
if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
self.warn_upon_invalid_slave(databyte)
self.state = cmd[8:] + ' REGS' # READ REGS / WRITE REGS
elif self.state in ('READ REGS', 'WRITE REGS'):
if cmd in ('DATA READ', 'DATA WRITE'):
handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg)
handle_reg(databyte, cmd[5:]) # READ / WRITE
elif cmd == 'STOP':
# TODO: Any output?
self.state = 'IDLE'
else:
# self.putx([0, ['Ignoring: %s (data=%s)' % (cmd, databyte)]])
pass
|
