BULME_BHEL18 / LM75B

A feature complete driver for the LM75B temperature sensor from NXP.

Fork of LM75B by Neil Thiessen

LM75B.cpp@0:557a92280097, 2013-07-31 (annotated)

Committer:
neilt6
Date:
Wed Jul 31 22:04:57 2013 +0000
Revision:
0:557a92280097
Child:
1:3da8df4319e8
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
neilt6 0:557a92280097 1 /* mbed LM75B Library
neilt6 0:557a92280097 2 * Copyright (c) 2013 neilt6
neilt6 0:557a92280097 3 *
neilt6 0:557a92280097 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
neilt6 0:557a92280097 5 * of this software and associated documentation files (the "Software"), to deal
neilt6 0:557a92280097 6 * in the Software without restriction, including without limitation the rights
neilt6 0:557a92280097 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
neilt6 0:557a92280097 8 * copies of the Software, and to permit persons to whom the Software is
neilt6 0:557a92280097 9 * furnished to do so, subject to the following conditions:
neilt6 0:557a92280097 10 *
neilt6 0:557a92280097 11 * The above copyright notice and this permission notice shall be included in
neilt6 0:557a92280097 12 * all copies or substantial portions of the Software.
neilt6 0:557a92280097 13 *
neilt6 0:557a92280097 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
neilt6 0:557a92280097 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
neilt6 0:557a92280097 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
neilt6 0:557a92280097 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
neilt6 0:557a92280097 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
neilt6 0:557a92280097 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
neilt6 0:557a92280097 20 * THE SOFTWARE.
neilt6 0:557a92280097 21 */
neilt6 0:557a92280097 22
neilt6 0:557a92280097 23 #include "LM75B.h"
neilt6 0:557a92280097 24 #include "mbed.h"
neilt6 0:557a92280097 25
neilt6 0:557a92280097 26 LM75B::LM75B(PinName sda, PinName scl, int addr) : _i2c(sda, scl)
neilt6 0:557a92280097 27 {
neilt6 0:557a92280097 28 //Set the internal device address
neilt6 0:557a92280097 29 _addr = addr;
neilt6 0:557a92280097 30 }
neilt6 0:557a92280097 31
neilt6 0:557a92280097 32 LM75B_Power_t LM75B::getPowerMode(void)
neilt6 0:557a92280097 33 {
neilt6 0:557a92280097 34 //Read the 8-bit register value
neilt6 0:557a92280097 35 char value = _read8(LM75B_REG_CONF);
neilt6 0:557a92280097 36
neilt6 0:557a92280097 37 //Return the status of the SHUTDOWN bit
neilt6 0:557a92280097 38 if (value & (1 << 0))
neilt6 0:557a92280097 39 return LM75B_Power_Shutdown;
neilt6 0:557a92280097 40 else
neilt6 0:557a92280097 41 return LM75B_Power_Normal;
neilt6 0:557a92280097 42 }
neilt6 0:557a92280097 43
neilt6 0:557a92280097 44 void LM75B::setPowerMode(LM75B_Power_t mode)
neilt6 0:557a92280097 45 {
neilt6 0:557a92280097 46 //Read the current 8-bit register value
neilt6 0:557a92280097 47 char value = _read8(LM75B_REG_CONF);
neilt6 0:557a92280097 48
neilt6 0:557a92280097 49 //Set or clear the SHUTDOWN bit
neilt6 0:557a92280097 50 if (mode == LM75B_Power_Shutdown)
neilt6 0:557a92280097 51 value |= (1 << 0);
neilt6 0:557a92280097 52 else
neilt6 0:557a92280097 53 value &= ~(1 << 0);
neilt6 0:557a92280097 54
neilt6 0:557a92280097 55 //Write the value back out
neilt6 0:557a92280097 56 _write8(LM75B_REG_CONF, value);
neilt6 0:557a92280097 57 }
neilt6 0:557a92280097 58
neilt6 0:557a92280097 59 LM75B_OS_Mode_t LM75B::getOSMode(void)
neilt6 0:557a92280097 60 {
neilt6 0:557a92280097 61 //Read the 8-bit register value
neilt6 0:557a92280097 62 char value = _read8(LM75B_REG_CONF);
neilt6 0:557a92280097 63
neilt6 0:557a92280097 64 //Return the status of the OS_COMP_INT bit
neilt6 0:557a92280097 65 if (value & (1 << 1))
neilt6 0:557a92280097 66 return LM75B_OS_Interrupt;
neilt6 0:557a92280097 67 else
neilt6 0:557a92280097 68 return LM75B_OS_Comparator;
neilt6 0:557a92280097 69 }
neilt6 0:557a92280097 70
neilt6 0:557a92280097 71 void LM75B::setOSMode(LM75B_OS_Mode_t mode)
neilt6 0:557a92280097 72 {
neilt6 0:557a92280097 73 //Read the current 8-bit register value
neilt6 0:557a92280097 74 char value = _read8(LM75B_REG_CONF);
neilt6 0:557a92280097 75
neilt6 0:557a92280097 76 //Set or clear the OS_COMP_INT bit
neilt6 0:557a92280097 77 if (mode == LM75B_OS_Interrupt)
neilt6 0:557a92280097 78 value |= (1 << 1);
neilt6 0:557a92280097 79 else
neilt6 0:557a92280097 80 value &= ~(1 << 1);
neilt6 0:557a92280097 81
neilt6 0:557a92280097 82 //Write the value back out
neilt6 0:557a92280097 83 _write8(LM75B_REG_CONF, value);
neilt6 0:557a92280097 84 }
neilt6 0:557a92280097 85
neilt6 0:557a92280097 86 LM75B_OS_Polarity_t LM75B::getOSPolarity(void)
neilt6 0:557a92280097 87 {
neilt6 0:557a92280097 88 //Read the 8-bit register value
neilt6 0:557a92280097 89 char value = _read8(LM75B_REG_CONF);
neilt6 0:557a92280097 90
neilt6 0:557a92280097 91 //Return the status of the OS_POL bit
neilt6 0:557a92280097 92 if (value & (1 << 2))
neilt6 0:557a92280097 93 return LM75B_OS_ActiveHigh;
neilt6 0:557a92280097 94 else
neilt6 0:557a92280097 95 return LM75B_OS_ActiveLow;
neilt6 0:557a92280097 96 }
neilt6 0:557a92280097 97
neilt6 0:557a92280097 98 void LM75B::setOSPolarity(LM75B_OS_Polarity_t polarity)
neilt6 0:557a92280097 99 {
neilt6 0:557a92280097 100 //Read the current 8-bit register value
neilt6 0:557a92280097 101 char value = _read8(LM75B_REG_CONF);
neilt6 0:557a92280097 102
neilt6 0:557a92280097 103 //Set or clear the OS_POL bit
neilt6 0:557a92280097 104 if (polarity == LM75B_OS_ActiveHigh)
neilt6 0:557a92280097 105 value |= (1 << 2);
neilt6 0:557a92280097 106 else
neilt6 0:557a92280097 107 value &= ~(1 << 2);
neilt6 0:557a92280097 108
neilt6 0:557a92280097 109 //Write the value back out
neilt6 0:557a92280097 110 _write8(LM75B_REG_CONF, value);
neilt6 0:557a92280097 111 }
neilt6 0:557a92280097 112
neilt6 0:557a92280097 113 LM75B_OS_FaultQueue_t LM75B::getOSFaultQueue(void)
neilt6 0:557a92280097 114 {
neilt6 0:557a92280097 115 //Read the 8-bit register value
neilt6 0:557a92280097 116 char value = _read8(LM75B_REG_CONF);
neilt6 0:557a92280097 117
neilt6 0:557a92280097 118 //Return the status of the OS_F_QUE bits
neilt6 0:557a92280097 119 if ((value & (1 << 3)) && (value & (1 << 4)))
neilt6 0:557a92280097 120 return LM75B_OS_FaultQueue_6;
neilt6 0:557a92280097 121 else if (!(value & (1 << 3)) && (value & (1 << 4)))
neilt6 0:557a92280097 122 return LM75B_OS_FaultQueue_4;
neilt6 0:557a92280097 123 else if ((value & (1 << 3)) && !(value & (1 << 4)))
neilt6 0:557a92280097 124 return LM75B_OS_FaultQueue_2;
neilt6 0:557a92280097 125 else
neilt6 0:557a92280097 126 return LM75B_OS_FaultQueue_1;
neilt6 0:557a92280097 127 }
neilt6 0:557a92280097 128
neilt6 0:557a92280097 129 void LM75B::setOSFaultQueue(LM75B_OS_FaultQueue_t queue)
neilt6 0:557a92280097 130 {
neilt6 0:557a92280097 131 //Read the current 8-bit register value
neilt6 0:557a92280097 132 char value = _read8(LM75B_REG_CONF);
neilt6 0:557a92280097 133
neilt6 0:557a92280097 134 //Clear the old OS_F_QUE bits
neilt6 0:557a92280097 135 value &= ~(3 << 3);
neilt6 0:557a92280097 136
neilt6 0:557a92280097 137 //Set the new OS_F_QUE bits
neilt6 0:557a92280097 138 if (queue == LM75B_OS_FaultQueue_2)
neilt6 0:557a92280097 139 value |= (1 << 3);
neilt6 0:557a92280097 140 else if (queue == LM75B_OS_FaultQueue_4)
neilt6 0:557a92280097 141 value |= (2 << 3);
neilt6 0:557a92280097 142 else if (queue == LM75B_OS_FaultQueue_6)
neilt6 0:557a92280097 143 value |= (3 << 3);
neilt6 0:557a92280097 144
neilt6 0:557a92280097 145 //Write the value back out
neilt6 0:557a92280097 146 _write8(LM75B_REG_CONF, value);
neilt6 0:557a92280097 147 }
neilt6 0:557a92280097 148
neilt6 0:557a92280097 149 float LM75B::getAlertTemp(void)
neilt6 0:557a92280097 150 {
neilt6 0:557a92280097 151 //Use the 9-bit helper to read the TOS register
neilt6 0:557a92280097 152 return _readTempHelper(LM75B_REG_TOS);
neilt6 0:557a92280097 153 }
neilt6 0:557a92280097 154
neilt6 0:557a92280097 155 void LM75B::setAlertTemp(float temp)
neilt6 0:557a92280097 156 {
neilt6 0:557a92280097 157 //Use the 9-bit helper to write to the TOS register
neilt6 0:557a92280097 158 return _writeTempHelper(LM75B_REG_TOS, temp);
neilt6 0:557a92280097 159 }
neilt6 0:557a92280097 160
neilt6 0:557a92280097 161 float LM75B::getAlertHyst(void)
neilt6 0:557a92280097 162 {
neilt6 0:557a92280097 163 //Use the 9-bit helper to read the THYST register
neilt6 0:557a92280097 164 return _readTempHelper(LM75B_REG_THYST);
neilt6 0:557a92280097 165 }
neilt6 0:557a92280097 166
neilt6 0:557a92280097 167 void LM75B::setAlertHyst(float temp)
neilt6 0:557a92280097 168 {
neilt6 0:557a92280097 169 //Use the 9-bit helper to write to the THYST register
neilt6 0:557a92280097 170 return _writeTempHelper(LM75B_REG_THYST, temp);
neilt6 0:557a92280097 171 }
neilt6 0:557a92280097 172
neilt6 0:557a92280097 173 float LM75B::getTemp(void)
neilt6 0:557a92280097 174 {
neilt6 0:557a92280097 175 //Signed return value
neilt6 0:557a92280097 176 short value;
neilt6 0:557a92280097 177
neilt6 0:557a92280097 178 //Read the 11-bit raw temperature value
neilt6 0:557a92280097 179 value = _read16(LM75B_REG_TEMP) >> 5;
neilt6 0:557a92280097 180
neilt6 0:557a92280097 181 //Sign extend negative numbers
neilt6 0:557a92280097 182 if (value & (1 << 10))
neilt6 0:557a92280097 183 value |= 0xFC00;
neilt6 0:557a92280097 184
neilt6 0:557a92280097 185 //Return the temperature in °C
neilt6 0:557a92280097 186 return value * 0.125;
neilt6 0:557a92280097 187 }
neilt6 0:557a92280097 188
neilt6 0:557a92280097 189 char LM75B::_read8(char reg)
neilt6 0:557a92280097 190 {
neilt6 0:557a92280097 191 //Select the register
neilt6 0:557a92280097 192 _i2c.write(_addr, &reg, 1);
neilt6 0:557a92280097 193
neilt6 0:557a92280097 194 //Read the 8-bit register
neilt6 0:557a92280097 195 _i2c.read(_addr, &reg, 1);
neilt6 0:557a92280097 196
neilt6 0:557a92280097 197 //Return the byte
neilt6 0:557a92280097 198 return reg;
neilt6 0:557a92280097 199 }
neilt6 0:557a92280097 200
neilt6 0:557a92280097 201 void LM75B::_write8(char reg, char data)
neilt6 0:557a92280097 202 {
neilt6 0:557a92280097 203 //Create a temporary buffer
neilt6 0:557a92280097 204 char buff[2];
neilt6 0:557a92280097 205
neilt6 0:557a92280097 206 //Load the register address and 8-bit data
neilt6 0:557a92280097 207 buff[0] = reg;
neilt6 0:557a92280097 208 buff[1] = data;
neilt6 0:557a92280097 209
neilt6 0:557a92280097 210 //Write the data
neilt6 0:557a92280097 211 _i2c.write(_addr, buff, 2);
neilt6 0:557a92280097 212 }
neilt6 0:557a92280097 213
neilt6 0:557a92280097 214 unsigned short LM75B::_read16(char reg)
neilt6 0:557a92280097 215 {
neilt6 0:557a92280097 216 //Create a temporary buffer
neilt6 0:557a92280097 217 char buff[2];
neilt6 0:557a92280097 218
neilt6 0:557a92280097 219 //Select the register
neilt6 0:557a92280097 220 _i2c.write(_addr, &reg, 1);
neilt6 0:557a92280097 221
neilt6 0:557a92280097 222 //Read the 16-bit register
neilt6 0:557a92280097 223 _i2c.read(_addr, buff, 2);
neilt6 0:557a92280097 224
neilt6 0:557a92280097 225 //Return the combined 16-bit value
neilt6 0:557a92280097 226 return (buff[0] << 8) | buff[1];
neilt6 0:557a92280097 227 }
neilt6 0:557a92280097 228
neilt6 0:557a92280097 229 void LM75B::_write16(char reg, unsigned short data)
neilt6 0:557a92280097 230 {
neilt6 0:557a92280097 231 //Create a temporary buffer
neilt6 0:557a92280097 232 char buff[3];
neilt6 0:557a92280097 233
neilt6 0:557a92280097 234 //Load the register address and 16-bit data
neilt6 0:557a92280097 235 buff[0] = reg;
neilt6 0:557a92280097 236 buff[1] = data >> 8;
neilt6 0:557a92280097 237 buff[2] = data;
neilt6 0:557a92280097 238
neilt6 0:557a92280097 239 //Write the data
neilt6 0:557a92280097 240 _i2c.write(_addr, buff, 3);
neilt6 0:557a92280097 241 }
neilt6 0:557a92280097 242
neilt6 0:557a92280097 243 float LM75B::_readTempHelper(char reg)
neilt6 0:557a92280097 244 {
neilt6 0:557a92280097 245 //Signed return value
neilt6 0:557a92280097 246 short value;
neilt6 0:557a92280097 247
neilt6 0:557a92280097 248 //Read the 9-bit raw temperature value
neilt6 0:557a92280097 249 value = _read16(reg) >> 7;
neilt6 0:557a92280097 250
neilt6 0:557a92280097 251 //Sign extend negative numbers
neilt6 0:557a92280097 252 if (value & (1 << 8))
neilt6 0:557a92280097 253 value |= 0xFF00;
neilt6 0:557a92280097 254
neilt6 0:557a92280097 255 //Return the temperature in °C
neilt6 0:557a92280097 256 return value * 0.5;
neilt6 0:557a92280097 257 }
neilt6 0:557a92280097 258
neilt6 0:557a92280097 259 void LM75B::_writeTempHelper(char reg, float temp)
neilt6 0:557a92280097 260 {
neilt6 0:557a92280097 261 //Range limit temp
neilt6 0:557a92280097 262 if (temp < -55.0)
neilt6 0:557a92280097 263 temp = -55.0;
neilt6 0:557a92280097 264 else if (temp > 125.0)
neilt6 0:557a92280097 265 temp = 125.0;
neilt6 0:557a92280097 266
neilt6 0:557a92280097 267 //Extract and shift the signed integer
neilt6 0:557a92280097 268 short value = temp * 2;
neilt6 0:557a92280097 269 value <<= 7;
neilt6 0:557a92280097 270
neilt6 0:557a92280097 271 //Send the new value
neilt6 0:557a92280097 272 _write16(reg, value);
neilt6 0:557a92280097 273 }