]> sigrok.org Git - libsigrokdecode.git/blame_incremental - decoders/lm75/pd.py
license: remove FSF postal address from boiler plate license text
[libsigrokdecode.git] / decoders / lm75 / pd.py
... / ...
CommitLineData
1##
2## This file is part of the libsigrokdecode project.
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, see <http://www.gnu.org/licenses/>.
18##
19
20# TODO: Better support for various LM75 compatible devices.
21
22import sigrokdecode as srd
23
24# LM75 only supports 9 bit resolution, compatible devices usually 9-12 bits.
25resolution = {
26 # CONFIG[6:5]: <resolution>
27 0x00: 9,
28 0x01: 10,
29 0x02: 11,
30 0x03: 12,
31}
32
33ft = {
34 # CONFIG[4:3]: <fault tolerance setting>
35 0x00: 1,
36 0x01: 2,
37 0x02: 4,
38 0x03: 6,
39}
40
41class Decoder(srd.Decoder):
42 api_version = 2
43 id = 'lm75'
44 name = 'LM75'
45 longname = 'National LM75'
46 desc = 'National LM75 (and compatibles) temperature sensor.'
47 license = 'gplv2+'
48 inputs = ['i2c']
49 outputs = ['lm75']
50 options = (
51 {'id': 'sensor', 'desc': 'Sensor type', 'default': 'lm75',
52 'values': ('lm75',)},
53 {'id': 'resolution', 'desc': 'Resolution (bits)', 'default': 9,
54 'values': (9, 10, 11, 12)},
55 )
56 annotations = (
57 ('celsius', 'Temperature in degrees Celsius'),
58 ('kelvin', 'Temperature in Kelvin'),
59 ('text-verbose', 'Human-readable text (verbose)'),
60 ('text', 'Human-readable text'),
61 ('warnings', 'Human-readable warnings'),
62 )
63
64 def __init__(self):
65 self.state = 'IDLE'
66 self.reg = 0x00 # Currently selected register
67 self.databytes = []
68
69 def start(self):
70 self.out_ann = self.register(srd.OUTPUT_ANN)
71
72 def putx(self, data):
73 # Helper for annotations which span exactly one I²C packet.
74 self.put(self.ss, self.es, self.out_ann, data)
75
76 def putb(self, data):
77 # Helper for annotations which span a block of I²C packets.
78 self.put(self.ss_block, self.es_block, self.out_ann, data)
79
80 def warn_upon_invalid_slave(self, addr):
81 # LM75 and compatible devices have a 7-bit I²C slave address where
82 # the 4 MSBs are fixed to 1001, and the 3 LSBs are configurable.
83 # Thus, valid slave addresses (1001xxx) range from 0x48 to 0x4f.
84 if addr not in range(0x48, 0x4f + 1):
85 s = 'Warning: I²C slave 0x%02x not an LM75 compatible sensor.'
86 self.putx([4, [s % addr]])
87
88 def output_temperature(self, s, rw):
89 # TODO: Support for resolutions other than 9 bit.
90 before, after = self.databytes[0], (self.databytes[1] >> 7) * 5
91 celsius = float('%d.%d' % (before, after))
92 kelvin = celsius + 273.15
93 self.putb([0, ['%s: %.1f °C' % (s, celsius)]])
94 self.putb([1, ['%s: %.1f K' % (s, kelvin)]])
95
96 # Warn about the temperature register (0x00) being read-only.
97 if s == 'Temperature' and rw == 'WRITE':
98 s = 'Warning: The temperature register is read-only!'
99 self.putb([4, [s]])
100
101 def handle_temperature_reg(self, b, s, rw):
102 # Common helper for the temperature/T_HYST/T_OS registers.
103 if len(self.databytes) == 0:
104 self.ss_block = self.ss
105 self.databytes.append(b)
106 return
107 self.databytes.append(b)
108 self.es_block = self.es
109 self.output_temperature(s, rw)
110 self.databytes = []
111
112 def handle_reg_0x00(self, b, rw):
113 # Temperature register (16bits, read-only).
114 self.handle_temperature_reg(b, 'Temperature', rw)
115
116 def handle_reg_0x01(self, b, rw):
117 # Configuration register (8 bits, read/write).
118 # TODO: Bit-exact annotation ranges.
119
120 sd = b & (1 << 0)
121 tmp = 'normal operation' if (sd == 0) else 'shutdown mode'
122 s = 'SD = %d: %s\n' % (sd, tmp)
123 s2 = 'SD = %s, ' % tmp
124
125 cmp_int = b & (1 << 1)
126 tmp = 'comparator' if (cmp_int == 0) else 'interrupt'
127 s += 'CMP/INT = %d: %s mode\n' % (cmp_int, tmp)
128 s2 += 'CMP/INT = %s, ' % tmp
129
130 pol = b & (1 << 2)
131 tmp = 'low' if (pol == 0) else 'high'
132 s += 'POL = %d: OS polarity is active-%s\n' % (pol, tmp)
133 s2 += 'POL = active-%s, ' % tmp
134
135 bits = (b & ((1 << 4) | (1 << 3))) >> 3
136 s += 'Fault tolerance setting: %d bit(s)\n' % ft[bits]
137 s2 += 'FT = %d' % ft[bits]
138
139 # Not supported by LM75, but by various compatible devices.
140 if self.options['sensor'] != 'lm75': # TODO
141 bits = (b & ((1 << 6) | (1 << 5))) >> 5
142 s += 'Resolution: %d bits\n' % resolution[bits]
143 s2 += ', resolution = %d' % resolution[bits]
144
145 self.putx([2, [s]])
146 self.putx([3, [s2]])
147
148 def handle_reg_0x02(self, b, rw):
149 # T_HYST register (16 bits, read/write).
150 self.handle_temperature_reg(b, 'T_HYST trip temperature', rw)
151
152 def handle_reg_0x03(self, b, rw):
153 # T_OS register (16 bits, read/write).
154 self.handle_temperature_reg(b, 'T_OS trip temperature', rw)
155
156 def decode(self, ss, es, data):
157 cmd, databyte = data
158
159 # Store the start/end samples of this I²C packet.
160 self.ss, self.es = ss, es
161
162 # State machine.
163 if self.state == 'IDLE':
164 # Wait for an I²C START condition.
165 if cmd != 'START':
166 return
167 self.state = 'GET SLAVE ADDR'
168 elif self.state == 'GET SLAVE ADDR':
169 # Wait for an address read/write operation.
170 if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
171 self.warn_upon_invalid_slave(databyte)
172 self.state = cmd[8:] + ' REGS' # READ REGS / WRITE REGS
173 elif self.state in ('READ REGS', 'WRITE REGS'):
174 if cmd in ('DATA READ', 'DATA WRITE'):
175 handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg)
176 handle_reg(databyte, cmd[5:]) # READ / WRITE
177 elif cmd == 'STOP':
178 # TODO: Any output?
179 self.state = 'IDLE'
180 else:
181 # self.putx([0, ['Ignoring: %s (data=%s)' % (cmd, databyte)]])
182 pass