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44f7ba18 1##
50bd5d25 2## This file is part of the libsigrokdecode project.
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3##
4## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.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
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# National LM75 (and compatibles) temperature sensor protocol decoder
22
23# TODO: Better support for various LM75 compatible devices.
24
25import sigrokdecode as srd
26
27# LM75 only supports 9 bit resolution, compatible devices usually 9-12 bits.
28resolution = {
29 # CONFIG[6:5]: <resolution>
30 0x00: 9,
31 0x01: 10,
32 0x02: 11,
33 0x03: 12,
34}
35
36ft = {
37 # CONFIG[4:3]: <fault tolerance setting>
38 0x00: 1,
39 0x01: 2,
40 0x02: 4,
41 0x03: 6,
42}
43
44class Decoder(srd.Decoder):
45 api_version = 1
46 id = 'lm75'
47 name = 'LM75'
48 longname = 'National LM75'
d523eae6 49 desc = 'National LM75 (and compatibles) temperature sensor.'
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50 license = 'gplv2+'
51 inputs = ['i2c']
52 outputs = ['lm75']
53 probes = []
54 optional_probes = [
55 {'id': 'os', 'name': 'OS', 'desc': 'Overtemperature shutdown'},
56 {'id': 'a0', 'name': 'A0', 'desc': 'I2C slave address input 0'},
57 {'id': 'a1', 'name': 'A1', 'desc': 'I2C slave address input 1'},
58 {'id': 'a2', 'name': 'A2', 'desc': 'I2C slave address input 2'},
59 ]
60 options = {
61 'sensor': ['Sensor type', 'lm75'],
62 'resolution': ['Resolution', 9], # 9-12 bit, sensor/config dependent
63 }
64 annotations = [
65 ['Celsius', 'Temperature in degrees Celsius'],
f84d82c0 66 ['Kelvin', 'Temperature in Kelvin'],
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67 ['Text (verbose)', 'Human-readable text (verbose)'],
68 ['Text', 'Human-readable text'],
69 ['Warnings', 'Human-readable warnings'],
70 ]
71
72 def __init__(self, **kwargs):
73 self.state = 'IDLE'
74 self.reg = 0x00 # Currently selected register
75 self.databytes = []
44f7ba18 76
8915b346 77 def start(self):
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78 # self.out_proto = self.register(srd.OUTPUT_PYTHON)
79 self.out_ann = self.register(srd.OUTPUT_ANN)
44f7ba18 80
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81 def putx(self, data):
82 # Helper for annotations which span exactly one I2C packet.
83 self.put(self.ss, self.es, self.out_ann, data)
84
85 def putb(self, data):
86 # Helper for annotations which span a block of I2C packets.
87 self.put(self.block_start, self.block_end, self.out_ann, data)
88
89 def warn_upon_invalid_slave(self, addr):
90 # LM75 and compatible devices have a 7-bit I2C slave address where
91 # the 4 MSBs are fixed to 1001, and the 3 LSBs are configurable.
92 # Thus, valid slave addresses (1001xxx) range from 0x48 to 0x4f.
93 if addr not in range(0x48, 0x4f + 1):
94 s = 'Warning: I2C slave 0x%02x not an LM75 compatible sensor.'
95 self.putx([4, [s % addr]])
96
5b30440e 97 def output_temperature(self, s, rw):
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98 # TODO: Support for resolutions other than 9 bit.
99 before, after = self.databytes[0], (self.databytes[1] >> 7) * 5
100 celsius = float('%d.%d' % (before, after))
101 kelvin = celsius + 273.15
102 self.putb([0, ['%s: %.1f °C' % (s, celsius)]])
f84d82c0 103 self.putb([1, ['%s: %.1f K' % (s, kelvin)]])
44f7ba18 104
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105 # Warn about the temperature register (0x00) being read-only.
106 if s == 'Temperature' and rw == 'WRITE':
107 s = 'Warning: The temperature register is read-only!'
108 self.putb([4, [s]])
109
5b30440e 110 def handle_temperature_reg(self, b, s, rw):
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111 # Common helper for the temperature/T_HYST/T_OS registers.
112 if len(self.databytes) == 0:
113 self.block_start = self.ss
114 self.databytes.append(b)
115 return
116 self.databytes.append(b)
117 self.block_end = self.es
5b30440e 118 self.output_temperature(s, rw)
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119 self.databytes = []
120
5b30440e 121 def handle_reg_0x00(self, b, rw):
44f7ba18 122 # Temperature register (16bits, read-only).
5b30440e 123 self.handle_temperature_reg(b, 'Temperature', rw)
44f7ba18 124
5b30440e 125 def handle_reg_0x01(self, b, rw):
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126 # Configuration register (8 bits, read/write).
127 # TODO: Bit-exact annotation ranges.
128
129 sd = b & (1 << 0)
130 tmp = 'normal operation' if (sd == 0) else 'shutdown mode'
131 s = 'SD = %d: %s\n' % (sd, tmp)
132 s2 = 'SD = %s, ' % tmp
133
134 cmp_int = b & (1 << 1)
135 tmp = 'comparator' if (cmp_int == 0) else 'interrupt'
136 s += 'CMP/INT = %d: %s mode\n' % (cmp_int, tmp)
137 s2 += 'CMP/INT = %s, ' % tmp
138
139 pol = b & (1 << 2)
140 tmp = 'low' if (pol == 0) else 'high'
141 s += 'POL = %d: OS polarity is active-%s\n' % (pol, tmp)
142 s2 += 'POL = active-%s, ' % tmp
143
144 bits = (b & ((1 << 4) | (1 << 3))) >> 3
145 s += 'Fault tolerance setting: %d bit(s)\n' % ft[bits]
146 s2 += 'FT = %d' % ft[bits]
147
148 # Not supported by LM75, but by various compatible devices.
149 if self.options['sensor'] != 'lm75': # TODO
150 bits = (b & ((1 << 6) | (1 << 5))) >> 5
151 s += 'Resolution: %d bits\n' % resolution[bits]
152 s2 += ', resolution = %d' % resolution[bits]
153
154 self.putx([2, [s]])
155 self.putx([3, [s2]])
156
5b30440e 157 def handle_reg_0x02(self, b, rw):
44f7ba18 158 # T_HYST register (16 bits, read/write).
5b30440e 159 self.handle_temperature_reg(b, 'T_HYST trip temperature', rw)
44f7ba18 160
5b30440e 161 def handle_reg_0x03(self, b, rw):
44f7ba18 162 # T_OS register (16 bits, read/write).
5b30440e 163 self.handle_temperature_reg(b, 'T_OS trip temperature', rw)
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164
165 def decode(self, ss, es, data):
166 cmd, databyte = data
167
168 # Store the start/end samples of this I2C packet.
169 self.ss, self.es = ss, es
170
171 # State machine.
172 if self.state == 'IDLE':
173 # Wait for an I2C START condition.
174 if cmd != 'START':
175 return
176 self.state = 'GET SLAVE ADDR'
177 elif self.state == 'GET SLAVE ADDR':
178 # Wait for an address read/write operation.
5b30440e 179 if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
44f7ba18 180 self.warn_upon_invalid_slave(databyte)
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181 self.state = cmd[8:] + ' REGS' # READ REGS / WRITE REGS
182 elif self.state in ('READ REGS', 'WRITE REGS'):
183 if cmd in ('DATA READ', 'DATA WRITE'):
44f7ba18 184 handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg)
5b30440e 185 handle_reg(databyte, cmd[5:]) # READ / WRITE
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186 elif cmd == 'STOP':
187 # TODO: Any output?
188 self.state = 'IDLE'
189 else:
190 # self.putx([0, ['Ignoring: %s (data=%s)' % (cmd, databyte)]])
191 pass
192 else:
193 raise Exception('Invalid state: %s' % self.state)
194