2 ## This file is part of the libsigrokdecode 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, see <http://www.gnu.org/licenses/>.
20 # TODO: Better support for various LM75 compatible devices.
22 import sigrokdecode as srd
24 # LM75 only supports 9 bit resolution, compatible devices usually 9-12 bits.
26 # CONFIG[6:5]: <resolution>
34 # CONFIG[4:3]: <fault tolerance setting>
41 class Decoder(srd.Decoder):
45 longname = 'National LM75'
46 desc = 'National LM75 (and compatibles) temperature sensor.'
52 {'id': 'sensor', 'desc': 'Sensor type', 'default': 'lm75',
54 {'id': 'resolution', 'desc': 'Resolution (bits)', 'default': 9,
55 'values': (9, 10, 11, 12)},
58 ('celsius', 'Temperature / °C'),
59 ('kelvin', 'Temperature / Kelvin'),
60 ('text-verbose', 'Text (verbose)'),
62 ('warning', 'Warning'),
70 self.reg = 0x00 # Currently selected register
74 self.out_ann = self.register(srd.OUTPUT_ANN)
77 # Helper for annotations which span exactly one I²C packet.
78 self.put(self.ss, self.es, self.out_ann, data)
81 # Helper for annotations which span a block of I²C packets.
82 self.put(self.ss_block, self.es_block, self.out_ann, data)
84 def warn_upon_invalid_slave(self, addr):
85 # LM75 and compatible devices have a 7-bit I²C slave address where
86 # the 4 MSBs are fixed to 1001, and the 3 LSBs are configurable.
87 # Thus, valid slave addresses (1001xxx) range from 0x48 to 0x4f.
88 if addr not in range(0x48, 0x4f + 1):
89 s = 'Warning: I²C slave 0x%02x not an LM75 compatible sensor.'
90 self.putx([4, [s % addr]])
92 def output_temperature(self, s, rw):
93 # TODO: Support for resolutions other than 9 bit.
94 before, after = self.databytes[0], (self.databytes[1] >> 7) * 5
95 celsius = float('%d.%d' % (before, after))
96 kelvin = celsius + 273.15
97 self.putb([0, ['%s: %.1f °C' % (s, celsius)]])
98 self.putb([1, ['%s: %.1f K' % (s, kelvin)]])
100 # Warn about the temperature register (0x00) being read-only.
101 if s == 'Temperature' and rw == 'WRITE':
102 s = 'Warning: The temperature register is read-only!'
105 def handle_temperature_reg(self, b, s, rw):
106 # Common helper for the temperature/T_HYST/T_OS registers.
107 if len(self.databytes) == 0:
108 self.ss_block = self.ss
109 self.databytes.append(b)
111 self.databytes.append(b)
112 self.es_block = self.es
113 self.output_temperature(s, rw)
116 def handle_reg_0x00(self, b, rw):
117 # Temperature register (16bits, read-only).
118 self.handle_temperature_reg(b, 'Temperature', rw)
120 def handle_reg_0x01(self, b, rw):
121 # Configuration register (8 bits, read/write).
122 # TODO: Bit-exact annotation ranges.
125 tmp = 'normal operation' if (sd == 0) else 'shutdown mode'
126 s = 'SD = %d: %s\n' % (sd, tmp)
127 s2 = 'SD = %s, ' % tmp
129 cmp_int = b & (1 << 1)
130 tmp = 'comparator' if (cmp_int == 0) else 'interrupt'
131 s += 'CMP/INT = %d: %s mode\n' % (cmp_int, tmp)
132 s2 += 'CMP/INT = %s, ' % tmp
135 tmp = 'low' if (pol == 0) else 'high'
136 s += 'POL = %d: OS polarity is active-%s\n' % (pol, tmp)
137 s2 += 'POL = active-%s, ' % tmp
139 bits = (b & ((1 << 4) | (1 << 3))) >> 3
140 s += 'Fault tolerance setting: %d bit(s)\n' % ft[bits]
141 s2 += 'FT = %d' % ft[bits]
143 # Not supported by LM75, but by various compatible devices.
144 if self.options['sensor'] != 'lm75': # TODO
145 bits = (b & ((1 << 6) | (1 << 5))) >> 5
146 s += 'Resolution: %d bits\n' % resolution[bits]
147 s2 += ', resolution = %d' % resolution[bits]
152 def handle_reg_0x02(self, b, rw):
153 # T_HYST register (16 bits, read/write).
154 self.handle_temperature_reg(b, 'T_HYST trip temperature', rw)
156 def handle_reg_0x03(self, b, rw):
157 # T_OS register (16 bits, read/write).
158 self.handle_temperature_reg(b, 'T_OS trip temperature', rw)
160 def decode(self, ss, es, data):
163 # Store the start/end samples of this I²C packet.
164 self.ss, self.es = ss, es
167 if self.state == 'IDLE':
168 # Wait for an I²C START condition.
171 self.state = 'GET SLAVE ADDR'
172 elif self.state == 'GET SLAVE ADDR':
173 # Wait for an address read/write operation.
174 if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
175 self.warn_upon_invalid_slave(databyte)
176 self.state = cmd[8:] + ' REGS' # READ REGS / WRITE REGS
177 elif self.state in ('READ REGS', 'WRITE REGS'):
178 if cmd in ('DATA READ', 'DATA WRITE'):
179 handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg)
180 handle_reg(databyte, cmd[5:]) # READ / WRITE
185 # self.putx([0, ['Ignoring: %s (data=%s)' % (cmd, databyte)]])