Olawale Komolafe / LM75B

temperature library

Fork of LM75B by Chris Styles

LM75B.cpp@2:cc474eead249, 2016-02-24 (annotated)

Committer:
co838_ok87
Date:
Wed Feb 24 15:50:09 2016 +0000
Revision:
2:cc474eead249
Parent:
1:6a70c9303bbe 
ok87

; changes to lm75b from chris styles.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
co838_ok87 2:cc474eead249 1 /* LM75B Driver Library
co838_ok87 2:cc474eead249 2 * Copyright (c) 2013 Neil Thiessen
co838_ok87 2:cc474eead249 3 *
co838_ok87 2:cc474eead249 4 * Licensed under the Apache License, Version 2.0 (the "License");
co838_ok87 2:cc474eead249 5 * you may not use this file except in compliance with the License.
co838_ok87 2:cc474eead249 6 * You may obtain a copy of the License at
co838_ok87 2:cc474eead249 7 *
co838_ok87 2:cc474eead249 8 * http://www.apache.org/licenses/LICENSE-2.0
co838_ok87 2:cc474eead249 9 *
co838_ok87 2:cc474eead249 10 * Unless required by applicable law or agreed to in writing, software
co838_ok87 2:cc474eead249 11 * distributed under the License is distributed on an "AS IS" BASIS,
co838_ok87 2:cc474eead249 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
co838_ok87 2:cc474eead249 13 * See the License for the specific language governing permissions and
co838_ok87 2:cc474eead249 14 * limitations under the License.
co838_ok87 2:cc474eead249 15 */
co838_ok87 2:cc474eead249 16
chris 0:1be38995591b 17 #include "LM75B.h"
chris 0:1be38995591b 18
co838_ok87 2:cc474eead249 19 LM75B::LM75B(PinName sda, PinName scl, Address addr) : m_I2C(sda, scl)
co838_ok87 2:cc474eead249 20 {
co838_ok87 2:cc474eead249 21 //Set the internal device address
co838_ok87 2:cc474eead249 22 m_Addr = (int)addr;
co838_ok87 2:cc474eead249 23 }
co838_ok87 2:cc474eead249 24
co838_ok87 2:cc474eead249 25 bool LM75B::open(void)
co838_ok87 2:cc474eead249 26 {
co838_ok87 2:cc474eead249 27 //Probe for the LM75B using a Zero Length Transfer
co838_ok87 2:cc474eead249 28 if (!m_I2C.write(m_Addr, NULL, 0)) {
co838_ok87 2:cc474eead249 29 //Reset the device to default configuration
co838_ok87 2:cc474eead249 30 write8(REG_CONF, 0x00);
co838_ok87 2:cc474eead249 31 write16(REG_THYST, 0x4B00);
co838_ok87 2:cc474eead249 32 write16(REG_TOS, 0x5000);
co838_ok87 2:cc474eead249 33
co838_ok87 2:cc474eead249 34 //Return success
co838_ok87 2:cc474eead249 35 return true;
co838_ok87 2:cc474eead249 36 } else {
co838_ok87 2:cc474eead249 37 //Return failure
co838_ok87 2:cc474eead249 38 return false;
co838_ok87 2:cc474eead249 39 }
co838_ok87 2:cc474eead249 40 }
co838_ok87 2:cc474eead249 41
co838_ok87 2:cc474eead249 42 LM75B::PowerMode LM75B::powerMode(void)
co838_ok87 2:cc474eead249 43 {
co838_ok87 2:cc474eead249 44 //Read the 8-bit register value
co838_ok87 2:cc474eead249 45 char value = read8(REG_CONF);
co838_ok87 2:cc474eead249 46
co838_ok87 2:cc474eead249 47 //Return the status of the SHUTDOWN bit
co838_ok87 2:cc474eead249 48 if (value & (1 << 0))
co838_ok87 2:cc474eead249 49 return POWER_SHUTDOWN;
co838_ok87 2:cc474eead249 50 else
co838_ok87 2:cc474eead249 51 return POWER_NORMAL;
co838_ok87 2:cc474eead249 52 }
co838_ok87 2:cc474eead249 53
co838_ok87 2:cc474eead249 54 void LM75B::powerMode(PowerMode mode)
co838_ok87 2:cc474eead249 55 {
co838_ok87 2:cc474eead249 56 //Read the current 8-bit register value
co838_ok87 2:cc474eead249 57 char value = read8(REG_CONF);
co838_ok87 2:cc474eead249 58
co838_ok87 2:cc474eead249 59 //Set or clear the SHUTDOWN bit
co838_ok87 2:cc474eead249 60 if (mode == POWER_SHUTDOWN)
co838_ok87 2:cc474eead249 61 value |= (1 << 0);
co838_ok87 2:cc474eead249 62 else
co838_ok87 2:cc474eead249 63 value &= ~(1 << 0);
co838_ok87 2:cc474eead249 64
co838_ok87 2:cc474eead249 65 //Write the value back out
co838_ok87 2:cc474eead249 66 write8(REG_CONF, value);
co838_ok87 2:cc474eead249 67 }
co838_ok87 2:cc474eead249 68
co838_ok87 2:cc474eead249 69 LM75B::OSMode LM75B::osMode(void)
chris 0:1be38995591b 70 {
co838_ok87 2:cc474eead249 71 //Read the 8-bit register value
co838_ok87 2:cc474eead249 72 char value = read8(REG_CONF);
co838_ok87 2:cc474eead249 73
co838_ok87 2:cc474eead249 74 //Return the status of the OS_COMP_INT bit
co838_ok87 2:cc474eead249 75 if (value & (1 << 1))
co838_ok87 2:cc474eead249 76 return OS_INTERRUPT;
co838_ok87 2:cc474eead249 77 else
co838_ok87 2:cc474eead249 78 return OS_COMPARATOR;
co838_ok87 2:cc474eead249 79 }
co838_ok87 2:cc474eead249 80
co838_ok87 2:cc474eead249 81 void LM75B::osMode(OSMode mode)
co838_ok87 2:cc474eead249 82 {
co838_ok87 2:cc474eead249 83 //Read the current 8-bit register value
co838_ok87 2:cc474eead249 84 char value = read8(REG_CONF);
co838_ok87 2:cc474eead249 85
co838_ok87 2:cc474eead249 86 //Set or clear the OS_COMP_INT bit
co838_ok87 2:cc474eead249 87 if (mode == OS_INTERRUPT)
co838_ok87 2:cc474eead249 88 value |= (1 << 1);
co838_ok87 2:cc474eead249 89 else
co838_ok87 2:cc474eead249 90 value &= ~(1 << 1);
co838_ok87 2:cc474eead249 91
co838_ok87 2:cc474eead249 92 //Write the value back out
co838_ok87 2:cc474eead249 93 write8(REG_CONF, value);
co838_ok87 2:cc474eead249 94 }
co838_ok87 2:cc474eead249 95
co838_ok87 2:cc474eead249 96 LM75B::OSPolarity LM75B::osPolarity(void)
co838_ok87 2:cc474eead249 97 {
co838_ok87 2:cc474eead249 98 //Read the 8-bit register value
co838_ok87 2:cc474eead249 99 char value = read8(REG_CONF);
co838_ok87 2:cc474eead249 100
co838_ok87 2:cc474eead249 101 //Return the status of the OS_POL bit
co838_ok87 2:cc474eead249 102 if (value & (1 << 2))
co838_ok87 2:cc474eead249 103 return OS_ACTIVE_HIGH;
co838_ok87 2:cc474eead249 104 else
co838_ok87 2:cc474eead249 105 return OS_ACTIVE_LOW;
co838_ok87 2:cc474eead249 106 }
co838_ok87 2:cc474eead249 107
co838_ok87 2:cc474eead249 108 void LM75B::osPolarity(OSPolarity polarity)
co838_ok87 2:cc474eead249 109 {
co838_ok87 2:cc474eead249 110 //Read the current 8-bit register value
co838_ok87 2:cc474eead249 111 char value = read8(REG_CONF);
co838_ok87 2:cc474eead249 112
co838_ok87 2:cc474eead249 113 //Set or clear the OS_POL bit
co838_ok87 2:cc474eead249 114 if (polarity == OS_ACTIVE_HIGH)
co838_ok87 2:cc474eead249 115 value |= (1 << 2);
co838_ok87 2:cc474eead249 116 else
co838_ok87 2:cc474eead249 117 value &= ~(1 << 2);
co838_ok87 2:cc474eead249 118
co838_ok87 2:cc474eead249 119 //Write the value back out
co838_ok87 2:cc474eead249 120 write8(REG_CONF, value);
co838_ok87 2:cc474eead249 121 }
co838_ok87 2:cc474eead249 122
co838_ok87 2:cc474eead249 123 LM75B::OSFaultQueue LM75B::osFaultQueue(void)
co838_ok87 2:cc474eead249 124 {
co838_ok87 2:cc474eead249 125 //Read the 8-bit register value
co838_ok87 2:cc474eead249 126 char value = read8(REG_CONF);
co838_ok87 2:cc474eead249 127
co838_ok87 2:cc474eead249 128 //Return the status of the OS_F_QUE bits
co838_ok87 2:cc474eead249 129 if ((value & (1 << 3)) && (value & (1 << 4)))
co838_ok87 2:cc474eead249 130 return OS_FAULT_QUEUE_6;
co838_ok87 2:cc474eead249 131 else if (!(value & (1 << 3)) && (value & (1 << 4)))
co838_ok87 2:cc474eead249 132 return OS_FAULT_QUEUE_4;
co838_ok87 2:cc474eead249 133 else if ((value & (1 << 3)) && !(value & (1 << 4)))
co838_ok87 2:cc474eead249 134 return OS_FAULT_QUEUE_2;
co838_ok87 2:cc474eead249 135 else
co838_ok87 2:cc474eead249 136 return OS_FAULT_QUEUE_1;
chris 0:1be38995591b 137 }
chris 0:1be38995591b 138
co838_ok87 2:cc474eead249 139 void LM75B::osFaultQueue(OSFaultQueue queue)
co838_ok87 2:cc474eead249 140 {
co838_ok87 2:cc474eead249 141 //Read the current 8-bit register value
co838_ok87 2:cc474eead249 142 char value = read8(REG_CONF);
chris 0:1be38995591b 143
co838_ok87 2:cc474eead249 144 //Clear the old OS_F_QUE bits
co838_ok87 2:cc474eead249 145 value &= ~(3 << 3);
co838_ok87 2:cc474eead249 146
co838_ok87 2:cc474eead249 147 //Set the new OS_F_QUE bits
co838_ok87 2:cc474eead249 148 if (queue == OS_FAULT_QUEUE_2)
co838_ok87 2:cc474eead249 149 value |= (1 << 3);
co838_ok87 2:cc474eead249 150 else if (queue == OS_FAULT_QUEUE_4)
co838_ok87 2:cc474eead249 151 value |= (2 << 3);
co838_ok87 2:cc474eead249 152 else if (queue == OS_FAULT_QUEUE_6)
co838_ok87 2:cc474eead249 153 value |= (3 << 3);
co838_ok87 2:cc474eead249 154
co838_ok87 2:cc474eead249 155 //Write the value back out
co838_ok87 2:cc474eead249 156 write8(REG_CONF, value);
co838_ok87 2:cc474eead249 157 }
co838_ok87 2:cc474eead249 158
co838_ok87 2:cc474eead249 159 float LM75B::alertTemp(void)
co838_ok87 2:cc474eead249 160 {
co838_ok87 2:cc474eead249 161 //Use the 9-bit helper to read the TOS register
co838_ok87 2:cc474eead249 162 return readAlertTempHelper(REG_TOS);
co838_ok87 2:cc474eead249 163 }
co838_ok87 2:cc474eead249 164
co838_ok87 2:cc474eead249 165 void LM75B::alertTemp(float temp)
co838_ok87 2:cc474eead249 166 {
co838_ok87 2:cc474eead249 167 //Use the 9-bit helper to write to the TOS register
co838_ok87 2:cc474eead249 168 return writeAlertTempHelper(REG_TOS, temp);
co838_ok87 2:cc474eead249 169 }
chris 0:1be38995591b 170
co838_ok87 2:cc474eead249 171 float LM75B::alertHyst(void)
co838_ok87 2:cc474eead249 172 {
co838_ok87 2:cc474eead249 173 //Use the 9-bit helper to read the THYST register
co838_ok87 2:cc474eead249 174 return readAlertTempHelper(REG_THYST);
co838_ok87 2:cc474eead249 175 }
co838_ok87 2:cc474eead249 176
co838_ok87 2:cc474eead249 177 void LM75B::alertHyst(float temp)
co838_ok87 2:cc474eead249 178 {
co838_ok87 2:cc474eead249 179 //Use the 9-bit helper to write to the THYST register
co838_ok87 2:cc474eead249 180 return writeAlertTempHelper(REG_THYST, temp);
co838_ok87 2:cc474eead249 181 }
co838_ok87 2:cc474eead249 182
co838_ok87 2:cc474eead249 183 float LM75B::temp(void)
chris 0:1be38995591b 184 {
co838_ok87 2:cc474eead249 185 //Signed return value
co838_ok87 2:cc474eead249 186 short value;
chris 0:1be38995591b 187
co838_ok87 2:cc474eead249 188 //Read the 11-bit raw temperature value
co838_ok87 2:cc474eead249 189 value = read16(REG_TEMP) >> 5;
co838_ok87 2:cc474eead249 190
co838_ok87 2:cc474eead249 191 //Sign extend negative numbers
co838_ok87 2:cc474eead249 192 if (value & (1 << 10))
co838_ok87 2:cc474eead249 193 value |= 0xFC00;
co838_ok87 2:cc474eead249 194
co838_ok87 2:cc474eead249 195 //Return the temperature in °C
co838_ok87 2:cc474eead249 196 return value * 0.125;
co838_ok87 2:cc474eead249 197 }
co838_ok87 2:cc474eead249 198
co838_ok87 2:cc474eead249 199 char LM75B::read8(char reg)
co838_ok87 2:cc474eead249 200 {
co838_ok87 2:cc474eead249 201 //Select the register
co838_ok87 2:cc474eead249 202 m_I2C.write(m_Addr, &reg, 1);
co838_ok87 2:cc474eead249 203
co838_ok87 2:cc474eead249 204 //Read the 8-bit register
co838_ok87 2:cc474eead249 205 m_I2C.read(m_Addr, &reg, 1);
co838_ok87 2:cc474eead249 206
co838_ok87 2:cc474eead249 207 //Return the byte
co838_ok87 2:cc474eead249 208 return reg;
chris 0:1be38995591b 209 }
chris 0:1be38995591b 210
co838_ok87 2:cc474eead249 211 void LM75B::write8(char reg, char data)
co838_ok87 2:cc474eead249 212 {
co838_ok87 2:cc474eead249 213 //Create a temporary buffer
co838_ok87 2:cc474eead249 214 char buff[2];
co838_ok87 2:cc474eead249 215
co838_ok87 2:cc474eead249 216 //Load the register address and 8-bit data
co838_ok87 2:cc474eead249 217 buff[0] = reg;
co838_ok87 2:cc474eead249 218 buff[1] = data;
co838_ok87 2:cc474eead249 219
co838_ok87 2:cc474eead249 220 //Write the data
co838_ok87 2:cc474eead249 221 m_I2C.write(m_Addr, buff, 2);
co838_ok87 2:cc474eead249 222 }
co838_ok87 2:cc474eead249 223
co838_ok87 2:cc474eead249 224 unsigned short LM75B::read16(char reg)
co838_ok87 2:cc474eead249 225 {
co838_ok87 2:cc474eead249 226 //Create a temporary buffer
co838_ok87 2:cc474eead249 227 char buff[2];
co838_ok87 2:cc474eead249 228
co838_ok87 2:cc474eead249 229 //Select the register
co838_ok87 2:cc474eead249 230 m_I2C.write(m_Addr, &reg, 1);
co838_ok87 2:cc474eead249 231
co838_ok87 2:cc474eead249 232 //Read the 16-bit register
co838_ok87 2:cc474eead249 233 m_I2C.read(m_Addr, buff, 2);
co838_ok87 2:cc474eead249 234
co838_ok87 2:cc474eead249 235 //Return the combined 16-bit value
co838_ok87 2:cc474eead249 236 return (buff[0] << 8) | buff[1];
co838_ok87 2:cc474eead249 237 }
co838_ok87 2:cc474eead249 238
co838_ok87 2:cc474eead249 239 void LM75B::write16(char reg, unsigned short data)
chris 0:1be38995591b 240 {
co838_ok87 2:cc474eead249 241 //Create a temporary buffer
co838_ok87 2:cc474eead249 242 char buff[3];
co838_ok87 2:cc474eead249 243
co838_ok87 2:cc474eead249 244 //Load the register address and 16-bit data
co838_ok87 2:cc474eead249 245 buff[0] = reg;
co838_ok87 2:cc474eead249 246 buff[1] = data >> 8;
co838_ok87 2:cc474eead249 247 buff[2] = data;
co838_ok87 2:cc474eead249 248
co838_ok87 2:cc474eead249 249 //Write the data
co838_ok87 2:cc474eead249 250 m_I2C.write(m_Addr, buff, 3);
chris 0:1be38995591b 251 }
co838_ok87 2:cc474eead249 252
co838_ok87 2:cc474eead249 253 float LM75B::readAlertTempHelper(char reg)
co838_ok87 2:cc474eead249 254 {
co838_ok87 2:cc474eead249 255 //Signed return value
co838_ok87 2:cc474eead249 256 short value;
co838_ok87 2:cc474eead249 257
co838_ok87 2:cc474eead249 258 //Read the 9-bit raw temperature value
co838_ok87 2:cc474eead249 259 value = read16(reg) >> 7;
co838_ok87 2:cc474eead249 260
co838_ok87 2:cc474eead249 261 //Sign extend negative numbers
co838_ok87 2:cc474eead249 262 if (value & (1 << 8))
co838_ok87 2:cc474eead249 263 value |= 0xFF00;
co838_ok87 2:cc474eead249 264
co838_ok87 2:cc474eead249 265 //Return the temperature in °C
co838_ok87 2:cc474eead249 266 return value * 0.5;
co838_ok87 2:cc474eead249 267 }
co838_ok87 2:cc474eead249 268
co838_ok87 2:cc474eead249 269 void LM75B::writeAlertTempHelper(char reg, float temp)
co838_ok87 2:cc474eead249 270 {
co838_ok87 2:cc474eead249 271 //Range limit temp
co838_ok87 2:cc474eead249 272 if (temp < -55.0)
co838_ok87 2:cc474eead249 273 temp = -55.0;
co838_ok87 2:cc474eead249 274 else if (temp > 125.0)
co838_ok87 2:cc474eead249 275 temp = 125.0;
co838_ok87 2:cc474eead249 276
co838_ok87 2:cc474eead249 277 //Extract and shift the signed integer
co838_ok87 2:cc474eead249 278 short value = temp * 2;
co838_ok87 2:cc474eead249 279 value <<= 7;
co838_ok87 2:cc474eead249 280
co838_ok87 2:cc474eead249 281 //Send the new value
co838_ok87 2:cc474eead249 282 write16(reg, value);
co838_ok87 2:cc474eead249 283 }