2 ## This file is part of the sigrok project.
4 ## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
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.
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.
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
21 # National LM75 (and compatibles) temperature sensor protocol decoder
23 # TODO: Better support for various LM75 compatible devices.
25 import sigrokdecode as srd
27 # LM75 only supports 9 bit resolution, compatible devices usually 9-12 bits.
29 # CONFIG[6:5]: <resolution>
37 # CONFIG[4:3]: <fault tolerance setting>
44 class Decoder(srd.Decoder):
48 longname = 'National LM75'
49 desc = 'National LM75 (and compatibles) temperature sensor protocol.'
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'},
61 'sensor': ['Sensor type', 'lm75'],
62 'resolution': ['Resolution', 9], # 9-12 bit, sensor/config dependent
65 ['Celsius', 'Temperature in degrees Celsius'],
66 ['Kelvin', 'Temperature in degrees Kelvin'],
67 ['Text (verbose)', 'Human-readable text (verbose)'],
68 ['Text', 'Human-readable text'],
69 ['Warnings', 'Human-readable warnings'],
72 def __init__(self, **kwargs):
74 self.reg = 0x00 # Currently selected register
80 def start(self, metadata):
81 # self.out_proto = self.add(srd.OUTPUT_PROTO, 'lm75')
82 self.out_ann = self.add(srd.OUTPUT_ANN, 'lm75')
85 # TODO: Output min/max/avg temperature.
89 # Helper for annotations which span exactly one I2C packet.
90 self.put(self.ss, self.es, self.out_ann, data)
93 # Helper for annotations which span a block of I2C packets.
94 self.put(self.block_start, self.block_end, self.out_ann, data)
96 def warn_upon_invalid_slave(self, addr):
97 # LM75 and compatible devices have a 7-bit I2C slave address where
98 # the 4 MSBs are fixed to 1001, and the 3 LSBs are configurable.
99 # Thus, valid slave addresses (1001xxx) range from 0x48 to 0x4f.
100 if addr not in range(0x48, 0x4f + 1):
101 s = 'Warning: I2C slave 0x%02x not an LM75 compatible sensor.'
102 self.putx([4, [s % addr]])
104 def output_temperature(self, s, rw):
105 # TODO: Support for resolutions other than 9 bit.
106 before, after = self.databytes[0], (self.databytes[1] >> 7) * 5
107 celsius = float('%d.%d' % (before, after))
108 kelvin = celsius + 273.15
109 self.putb([0, ['%s: %.1f °C' % (s, celsius)]])
110 self.putb([1, ['%s: %.1f °K' % (s, kelvin)]])
112 # Keep some statistics. Can be output in report(), for example.
113 if celsius < self.mintemp:
114 self.mintemp = celsius
115 if celsius > self.maxtemp:
116 self.maxtemp = celsius
119 def handle_temperature_reg(self, b, s, rw):
120 # Common helper for the temperature/T_HYST/T_OS registers.
121 if len(self.databytes) == 0:
122 self.block_start = self.ss
123 self.databytes.append(b)
125 self.databytes.append(b)
126 self.block_end = self.es
127 self.output_temperature(s, rw)
130 def handle_reg_0x00(self, b, rw):
131 # Temperature register (16bits, read-only).
132 self.handle_temperature_reg(b, 'Temperature', rw)
134 def handle_reg_0x01(self, b, rw):
135 # Configuration register (8 bits, read/write).
136 # TODO: Bit-exact annotation ranges.
139 tmp = 'normal operation' if (sd == 0) else 'shutdown mode'
140 s = 'SD = %d: %s\n' % (sd, tmp)
141 s2 = 'SD = %s, ' % tmp
143 cmp_int = b & (1 << 1)
144 tmp = 'comparator' if (cmp_int == 0) else 'interrupt'
145 s += 'CMP/INT = %d: %s mode\n' % (cmp_int, tmp)
146 s2 += 'CMP/INT = %s, ' % tmp
149 tmp = 'low' if (pol == 0) else 'high'
150 s += 'POL = %d: OS polarity is active-%s\n' % (pol, tmp)
151 s2 += 'POL = active-%s, ' % tmp
153 bits = (b & ((1 << 4) | (1 << 3))) >> 3
154 s += 'Fault tolerance setting: %d bit(s)\n' % ft[bits]
155 s2 += 'FT = %d' % ft[bits]
157 # Not supported by LM75, but by various compatible devices.
158 if self.options['sensor'] != 'lm75': # TODO
159 bits = (b & ((1 << 6) | (1 << 5))) >> 5
160 s += 'Resolution: %d bits\n' % resolution[bits]
161 s2 += ', resolution = %d' % resolution[bits]
166 def handle_reg_0x02(self, b, rw):
167 # T_HYST register (16 bits, read/write).
168 self.handle_temperature_reg(b, 'T_HYST trip temperature', rw)
170 def handle_reg_0x03(self, b, rw):
171 # T_OS register (16 bits, read/write).
172 self.handle_temperature_reg(b, 'T_OS trip temperature', rw)
174 def decode(self, ss, es, data):
177 # Store the start/end samples of this I2C packet.
178 self.ss, self.es = ss, es
181 if self.state == 'IDLE':
182 # Wait for an I2C START condition.
185 self.state = 'GET SLAVE ADDR'
186 elif self.state == 'GET SLAVE ADDR':
187 # Wait for an address read/write operation.
188 if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
189 self.warn_upon_invalid_slave(databyte)
190 self.state = cmd[8:] + ' REGS' # READ REGS / WRITE REGS
191 elif self.state in ('READ REGS', 'WRITE REGS'):
192 if cmd in ('DATA READ', 'DATA WRITE'):
193 handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg)
194 handle_reg(databyte, cmd[5:]) # READ / WRITE
199 # self.putx([0, ['Ignoring: %s (data=%s)' % (cmd, databyte)]])
202 raise Exception('Invalid state: %s' % self.state)