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##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
##
# TODO: Better support for various LM75 compatible devices.
import sigrokdecode as srd
# LM75 only supports 9 bit resolution, compatible devices usually 9-12 bits.
resolution = {
# CONFIG[6:5]: <resolution>
0x00: 9,
0x01: 10,
0x02: 11,
0x03: 12,
}
ft = {
# CONFIG[4:3]: <fault tolerance setting>
0x00: 1,
0x01: 2,
0x02: 4,
0x03: 6,
}
class Decoder(srd.Decoder):
api_version = 1
id = 'lm75'
name = 'LM75'
longname = 'National LM75'
desc = 'National LM75 (and compatibles) temperature sensor.'
license = 'gplv2+'
inputs = ['i2c']
outputs = ['lm75']
probes = []
optional_probes = [
{'id': 'os', 'name': 'OS', 'desc': 'Overtemperature shutdown'},
{'id': 'a0', 'name': 'A0', 'desc': 'I²C slave address input 0'},
{'id': 'a1', 'name': 'A1', 'desc': 'I²C slave address input 1'},
{'id': 'a2', 'name': 'A2', 'desc': 'I²C slave address input 2'},
]
options = {
'sensor': ['Sensor type', 'lm75'],
'resolution': ['Resolution', 9], # 9-12 bit, sensor/config dependent
}
annotations = [
['celsius', 'Temperature in degrees Celsius'],
['kelvin', 'Temperature in Kelvin'],
['text-verbose', 'Human-readable text (verbose)'],
['text', 'Human-readable text'],
['warnings', 'Human-readable warnings'],
]
def __init__(self, **kwargs):
self.state = 'IDLE'
self.reg = 0x00 # Currently selected register
self.databytes = []
def start(self):
# self.out_proto = self.register(srd.OUTPUT_PYTHON)
self.out_ann = self.register(srd.OUTPUT_ANN)
def putx(self, data):
# Helper for annotations which span exactly one I²C packet.
self.put(self.ss, self.es, self.out_ann, data)
def putb(self, data):
# Helper for annotations which span a block of I²C packets.
self.put(self.block_start, self.block_end, self.out_ann, data)
def warn_upon_invalid_slave(self, addr):
# LM75 and compatible devices have a 7-bit I²C slave address where
# the 4 MSBs are fixed to 1001, and the 3 LSBs are configurable.
# Thus, valid slave addresses (1001xxx) range from 0x48 to 0x4f.
if addr not in range(0x48, 0x4f + 1):
s = 'Warning: I²C slave 0x%02x not an LM75 compatible sensor.'
self.putx([4, [s % addr]])
def output_temperature(self, s, rw):
# TODO: Support for resolutions other than 9 bit.
before, after = self.databytes[0], (self.databytes[1] >> 7) * 5
celsius = float('%d.%d' % (before, after))
kelvin = celsius + 273.15
self.putb([0, ['%s: %.1f °C' % (s, celsius)]])
self.putb([1, ['%s: %.1f K' % (s, kelvin)]])
# Warn about the temperature register (0x00) being read-only.
if s == 'Temperature' and rw == 'WRITE':
s = 'Warning: The temperature register is read-only!'
self.putb([4, [s]])
def handle_temperature_reg(self, b, s, rw):
# Common helper for the temperature/T_HYST/T_OS registers.
if len(self.databytes) == 0:
self.block_start = self.ss
self.databytes.append(b)
return
self.databytes.append(b)
self.block_end = self.es
self.output_temperature(s, rw)
self.databytes = []
def handle_reg_0x00(self, b, rw):
# Temperature register (16bits, read-only).
self.handle_temperature_reg(b, 'Temperature', rw)
def handle_reg_0x01(self, b, rw):
# Configuration register (8 bits, read/write).
# TODO: Bit-exact annotation ranges.
sd = b & (1 << 0)
tmp = 'normal operation' if (sd == 0) else 'shutdown mode'
s = 'SD = %d: %s\n' % (sd, tmp)
s2 = 'SD = %s, ' % tmp
cmp_int = b & (1 << 1)
tmp = 'comparator' if (cmp_int == 0) else 'interrupt'
s += 'CMP/INT = %d: %s mode\n' % (cmp_int, tmp)
s2 += 'CMP/INT = %s, ' % tmp
pol = b & (1 << 2)
tmp = 'low' if (pol == 0) else 'high'
s += 'POL = %d: OS polarity is active-%s\n' % (pol, tmp)
s2 += 'POL = active-%s, ' % tmp
bits = (b & ((1 << 4) | (1 << 3))) >> 3
s += 'Fault tolerance setting: %d bit(s)\n' % ft[bits]
s2 += 'FT = %d' % ft[bits]
# Not supported by LM75, but by various compatible devices.
if self.options['sensor'] != 'lm75': # TODO
bits = (b & ((1 << 6) | (1 << 5))) >> 5
s += 'Resolution: %d bits\n' % resolution[bits]
s2 += ', resolution = %d' % resolution[bits]
self.putx([2, [s]])
self.putx([3, [s2]])
def handle_reg_0x02(self, b, rw):
# T_HYST register (16 bits, read/write).
self.handle_temperature_reg(b, 'T_HYST trip temperature', rw)
def handle_reg_0x03(self, b, rw):
# T_OS register (16 bits, read/write).
self.handle_temperature_reg(b, 'T_OS trip temperature', rw)
def decode(self, ss, es, data):
cmd, databyte = data
# Store the start/end samples of this I²C packet.
self.ss, self.es = ss, es
# State machine.
if self.state == 'IDLE':
# Wait for an I²C START condition.
if cmd != 'START':
return
self.state = 'GET SLAVE ADDR'
elif self.state == 'GET SLAVE ADDR':
# Wait for an address read/write operation.
if cmd in ('ADDRESS READ', 'ADDRESS WRITE'):
self.warn_upon_invalid_slave(databyte)
self.state = cmd[8:] + ' REGS' # READ REGS / WRITE REGS
elif self.state in ('READ REGS', 'WRITE REGS'):
if cmd in ('DATA READ', 'DATA WRITE'):
handle_reg = getattr(self, 'handle_reg_0x%02x' % self.reg)
handle_reg(databyte, cmd[5:]) # READ / WRITE
elif cmd == 'STOP':
# TODO: Any output?
self.state = 'IDLE'
else:
# self.putx([0, ['Ignoring: %s (data=%s)' % (cmd, databyte)]])
pass
else:
raise Exception('Invalid state: %s' % self.state)
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