## ## This file is part of the libsigrokdecode project. ## ## Copyright (C) 2012 Uwe Hermann ## ## 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]: 0x00: 9, 0x01: 10, 0x02: 11, 0x03: 12, } ft = { # CONFIG[4:3]: 0x00: 1, 0x01: 2, 0x02: 4, 0x03: 6, } class Decoder(srd.Decoder): api_version = 2 id = 'lm75' name = 'LM75' longname = 'National LM75' desc = 'National LM75 (and compatibles) temperature sensor.' license = 'gplv2+' inputs = ['i2c'] outputs = ['lm75'] options = ( {'id': 'sensor', 'desc': 'Sensor type', 'default': 'lm75', 'values': ('lm75',)}, {'id': 'resolution', 'desc': 'Resolution (bits)', 'default': 9, 'values': (9, 10, 11, 12)}, ) 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_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.ss_block, self.es_block, 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.ss_block = self.ss self.databytes.append(b) return self.databytes.append(b) self.es_block = 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