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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, 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 | ||
25 | import sigrokdecode as srd | |
26 | ||
27 | # LM75 only supports 9 bit resolution, compatible devices usually 9-12 bits. | |
28 | resolution = { | |
29 | # CONFIG[6:5]: <resolution> | |
30 | 0x00: 9, | |
31 | 0x01: 10, | |
32 | 0x02: 11, | |
33 | 0x03: 12, | |
34 | } | |
35 | ||
36 | ft = { | |
37 | # CONFIG[4:3]: <fault tolerance setting> | |
38 | 0x00: 1, | |
39 | 0x01: 2, | |
40 | 0x02: 4, | |
41 | 0x03: 6, | |
42 | } | |
43 | ||
44 | class Decoder(srd.Decoder): | |
45 | api_version = 1 | |
46 | id = 'lm75' | |
47 | name = 'LM75' | |
48 | longname = 'National LM75' | |
49 | desc = 'National LM75 (and compatibles) temperature sensor.' | |
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'], | |
66 | ['Kelvin', 'Temperature in Kelvin'], | |
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 = [] | |
76 | ||
77 | def start(self): | |
78 | # self.out_proto = self.register(srd.OUTPUT_PYTHON) | |
79 | self.out_ann = self.register(srd.OUTPUT_ANN) | |
80 | ||
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 | ||
97 | def output_temperature(self, s, rw): | |
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)]]) | |
103 | self.putb([1, ['%s: %.1f K' % (s, kelvin)]]) | |
104 | ||
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 | ||
110 | def handle_temperature_reg(self, b, s, rw): | |
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 | |
118 | self.output_temperature(s, rw) | |
119 | self.databytes = [] | |
120 | ||
121 | def handle_reg_0x00(self, b, rw): | |
122 | # Temperature register (16bits, read-only). | |
123 | self.handle_temperature_reg(b, 'Temperature', rw) | |
124 | ||
125 | def handle_reg_0x01(self, b, rw): | |
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 | ||
157 | def handle_reg_0x02(self, b, rw): | |
158 | # T_HYST register (16 bits, read/write). | |
159 | self.handle_temperature_reg(b, 'T_HYST trip temperature', rw) | |
160 | ||
161 | def handle_reg_0x03(self, b, rw): | |
162 | # T_OS register (16 bits, read/write). | |
163 | self.handle_temperature_reg(b, 'T_OS trip temperature', rw) | |
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. | |
179 | if cmd in ('ADDRESS READ', 'ADDRESS WRITE'): | |
180 | self.warn_upon_invalid_slave(databyte) | |
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'): | |
184 | handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg) | |
185 | handle_reg(databyte, cmd[5:]) # READ / WRITE | |
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 |