Paolo Patierno / SHTx

Humidity and Temperature Sensor - Sensirion SHT1x driver (with exported functions to use it from C code)

Dependents:   sht15_remote_monitoring

Fork of SHTx by Roy van Dam

sht15.cpp@2:7505a67001b4, 2015-11-15 (annotated)

Committer:
ppatierno
Date:
Sun Nov 15 15:13:08 2015 +0000
Revision:
2:7505a67001b4
Parent:
1:8465801be23f 
Added export layer to use SHTx from C code

Who changed what in which revision?

UserRevisionLine numberNew contents of line
NegativeBlack 1:8465801be23f 1 /**
NegativeBlack 1:8465801be23f 2 * Copyright (c) 2010 Roy van Dam <roy@negative-black.org>
NegativeBlack 1:8465801be23f 3 * All rights reserved.
NegativeBlack 1:8465801be23f 4 *
NegativeBlack 1:8465801be23f 5 * Redistribution and use in source and binary forms, with or without
NegativeBlack 1:8465801be23f 6 * modification, are permitted provided that the following conditions
NegativeBlack 1:8465801be23f 7 * are met:
NegativeBlack 1:8465801be23f 8 * 1. Redistributions of source code must retain the above copyright
NegativeBlack 1:8465801be23f 9 * notice, this list of conditions and the following disclaimer.
NegativeBlack 1:8465801be23f 10 * 2. Redistributions in binary form must reproduce the above copyright
NegativeBlack 1:8465801be23f 11 * notice, this list of conditions and the following disclaimer in the
NegativeBlack 1:8465801be23f 12 * documentation and/or other materials provided with the distribution.
NegativeBlack 1:8465801be23f 13 *
NegativeBlack 1:8465801be23f 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
NegativeBlack 1:8465801be23f 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
NegativeBlack 1:8465801be23f 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
NegativeBlack 1:8465801be23f 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
NegativeBlack 1:8465801be23f 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
NegativeBlack 1:8465801be23f 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
NegativeBlack 1:8465801be23f 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
NegativeBlack 1:8465801be23f 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
NegativeBlack 1:8465801be23f 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
NegativeBlack 1:8465801be23f 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
NegativeBlack 1:8465801be23f 24 * SUCH DAMAGE.
NegativeBlack 1:8465801be23f 25 */
NegativeBlack 1:8465801be23f 26
NegativeBlack 1:8465801be23f 27 #include "sht15.hpp"
NegativeBlack 1:8465801be23f 28
NegativeBlack 1:8465801be23f 29 namespace SHTx {
NegativeBlack 1:8465801be23f 30 SHT15::SHT15(PinName sda, PinName scl): i2c(sda, scl) {
NegativeBlack 1:8465801be23f 31 this->ready = true;
NegativeBlack 1:8465801be23f 32 wait_ms(11);
NegativeBlack 1:8465801be23f 33 }
NegativeBlack 1:8465801be23f 34
NegativeBlack 1:8465801be23f 35 float
NegativeBlack 1:8465801be23f 36 SHT15::getTemperature(void) {
NegativeBlack 1:8465801be23f 37 return this->convertTemperature(
NegativeBlack 1:8465801be23f 38 this->temperature,
NegativeBlack 1:8465801be23f 39 this->getFlag(flag_resolution),
NegativeBlack 1:8465801be23f 40 this->scale
NegativeBlack 1:8465801be23f 41 );
NegativeBlack 1:8465801be23f 42 }
NegativeBlack 1:8465801be23f 43
NegativeBlack 1:8465801be23f 44 float
NegativeBlack 1:8465801be23f 45 SHT15::getHumidity(void) {
NegativeBlack 1:8465801be23f 46 return this->convertHumidity(
NegativeBlack 1:8465801be23f 47 this->humidity,
NegativeBlack 1:8465801be23f 48 this->temperature,
NegativeBlack 1:8465801be23f 49 this->getFlag(flag_resolution)
NegativeBlack 1:8465801be23f 50 );
NegativeBlack 1:8465801be23f 51 }
NegativeBlack 1:8465801be23f 52
NegativeBlack 1:8465801be23f 53 bool
NegativeBlack 1:8465801be23f 54 SHT15::checkBattery(void) {
NegativeBlack 1:8465801be23f 55 this->readRegister(cmd_read_register);
NegativeBlack 1:8465801be23f 56 return this->getFlag(flag_battery);
NegativeBlack 1:8465801be23f 57 }
NegativeBlack 1:8465801be23f 58
NegativeBlack 1:8465801be23f 59 bool
NegativeBlack 1:8465801be23f 60 SHT15::setHeater(bool value) {
NegativeBlack 1:8465801be23f 61 this->setFlag(flag_heater, value);
NegativeBlack 1:8465801be23f 62 return this->writeRegister();
NegativeBlack 1:8465801be23f 63 }
NegativeBlack 1:8465801be23f 64
NegativeBlack 1:8465801be23f 65 bool
NegativeBlack 1:8465801be23f 66 SHT15::setResolution(bool value) {
NegativeBlack 1:8465801be23f 67 this->setFlag(flag_resolution, value);
NegativeBlack 1:8465801be23f 68 return this->writeRegister();
NegativeBlack 1:8465801be23f 69 }
NegativeBlack 1:8465801be23f 70
NegativeBlack 1:8465801be23f 71 bool
NegativeBlack 1:8465801be23f 72 SHT15::setOTPReload(bool value) {
NegativeBlack 1:8465801be23f 73 this->setFlag(flag_otp_reload, !value);
NegativeBlack 1:8465801be23f 74 return this->writeRegister();
NegativeBlack 1:8465801be23f 75 }
NegativeBlack 1:8465801be23f 76
NegativeBlack 1:8465801be23f 77 void
NegativeBlack 1:8465801be23f 78 SHT15::setScale(bool value) {
NegativeBlack 1:8465801be23f 79 this->scale = value;
NegativeBlack 1:8465801be23f 80 }
NegativeBlack 1:8465801be23f 81
NegativeBlack 1:8465801be23f 82 bool
NegativeBlack 1:8465801be23f 83 SHT15::update(void) {
NegativeBlack 1:8465801be23f 84 if ((this->ready == false) ||
NegativeBlack 1:8465801be23f 85 !this->readRegister(cmd_read_temperature) ||
NegativeBlack 1:8465801be23f 86 !this->readRegister(cmd_read_humidity)) {
NegativeBlack 1:8465801be23f 87 return false;
NegativeBlack 1:8465801be23f 88 }
NegativeBlack 1:8465801be23f 89
NegativeBlack 1:8465801be23f 90 return true;
NegativeBlack 1:8465801be23f 91 }
NegativeBlack 1:8465801be23f 92
NegativeBlack 1:8465801be23f 93 bool
NegativeBlack 1:8465801be23f 94 SHT15::reset(void) {
NegativeBlack 1:8465801be23f 95 while (this->ready == false) {
NegativeBlack 1:8465801be23f 96 continue;
NegativeBlack 1:8465801be23f 97 }
NegativeBlack 1:8465801be23f 98
NegativeBlack 1:8465801be23f 99 this->ready = false;
NegativeBlack 1:8465801be23f 100 this->i2c.start();
NegativeBlack 1:8465801be23f 101 bool ack = this->i2c.write(cmd_reset_device);
NegativeBlack 1:8465801be23f 102 this->i2c.stop();
NegativeBlack 1:8465801be23f 103 this->ready = true;
NegativeBlack 1:8465801be23f 104
NegativeBlack 1:8465801be23f 105 if (ack) {
NegativeBlack 1:8465801be23f 106 this->status_register = 0;
NegativeBlack 1:8465801be23f 107 this->humidity = 0;
NegativeBlack 1:8465801be23f 108 this->temperature = 0;
NegativeBlack 1:8465801be23f 109 wait_ms(11);
NegativeBlack 1:8465801be23f 110 return true;
NegativeBlack 1:8465801be23f 111 }
NegativeBlack 1:8465801be23f 112
NegativeBlack 1:8465801be23f 113 return false;
NegativeBlack 1:8465801be23f 114 }
NegativeBlack 1:8465801be23f 115
NegativeBlack 1:8465801be23f 116 void
NegativeBlack 1:8465801be23f 117 SHT15::connectionReset(void) {
NegativeBlack 1:8465801be23f 118 this->i2c.reset();
NegativeBlack 1:8465801be23f 119 }
NegativeBlack 1:8465801be23f 120
NegativeBlack 1:8465801be23f 121 float
NegativeBlack 1:8465801be23f 122 SHT15::convertTemperature(uint16_t sot, bool res, bool scale) {
NegativeBlack 1:8465801be23f 123 // Temperature conversion coefficients
NegativeBlack 1:8465801be23f 124 float d1 = this->coefficient.dv[scale];
NegativeBlack 1:8465801be23f 125 float d2 = ((scale) ? this->coefficient.df[res]
NegativeBlack 1:8465801be23f 126 : this->coefficient.dc[res]);
NegativeBlack 1:8465801be23f 127
NegativeBlack 1:8465801be23f 128 // Temperature data conversion
NegativeBlack 1:8465801be23f 129 return d1 + (d2 * (float)(sot));
NegativeBlack 1:8465801be23f 130 }
NegativeBlack 1:8465801be23f 131
NegativeBlack 1:8465801be23f 132 float
NegativeBlack 1:8465801be23f 133 SHT15::convertHumidity(uint16_t sohr, uint16_t sot, bool res) {
NegativeBlack 1:8465801be23f 134 // Humidity conversion coefficients
NegativeBlack 1:8465801be23f 135 float c1 = this->coefficient.c1[res];
NegativeBlack 1:8465801be23f 136 float c2 = this->coefficient.c2[res];
NegativeBlack 1:8465801be23f 137 float c3 = this->coefficient.c3[res];
NegativeBlack 1:8465801be23f 138
NegativeBlack 1:8465801be23f 139 // Temperature compensation coefficients
NegativeBlack 1:8465801be23f 140 float t1 = this->coefficient.t1[res];
NegativeBlack 1:8465801be23f 141 float t2 = this->coefficient.t2[res];
NegativeBlack 1:8465801be23f 142
NegativeBlack 1:8465801be23f 143 // Temperature data conversion to celcius
NegativeBlack 1:8465801be23f 144 float temp = this->convertTemperature(sot, res, false);
NegativeBlack 1:8465801be23f 145
NegativeBlack 1:8465801be23f 146 // Humidity data conversion to relative humidity
NegativeBlack 1:8465801be23f 147 float humid = c1 + (c2 * (float)(sohr)) + (c3 * (float)(sohr * sohr));
NegativeBlack 1:8465801be23f 148
NegativeBlack 1:8465801be23f 149 // Calculate temperature compensation
NegativeBlack 1:8465801be23f 150 return (temp - 25) + (t1 + (t2 * (float)(sohr)) + humid);
NegativeBlack 1:8465801be23f 151 }
NegativeBlack 1:8465801be23f 152
NegativeBlack 1:8465801be23f 153 bool
NegativeBlack 1:8465801be23f 154 SHT15::writeRegister(void) {
NegativeBlack 1:8465801be23f 155 while (this->ready == false) {
NegativeBlack 1:8465801be23f 156 continue;
NegativeBlack 1:8465801be23f 157 }
NegativeBlack 1:8465801be23f 158
NegativeBlack 1:8465801be23f 159 this->ready = false;
NegativeBlack 1:8465801be23f 160 this->i2c.start();
NegativeBlack 1:8465801be23f 161
NegativeBlack 1:8465801be23f 162 if (this->i2c.write(cmd_write_register)) {
NegativeBlack 1:8465801be23f 163 this->i2c.write(this->status_register);
NegativeBlack 1:8465801be23f 164 }
NegativeBlack 1:8465801be23f 165
NegativeBlack 1:8465801be23f 166 this->i2c.stop();
NegativeBlack 1:8465801be23f 167 this->ready = true;
NegativeBlack 1:8465801be23f 168
NegativeBlack 1:8465801be23f 169 return true;
NegativeBlack 1:8465801be23f 170 }
NegativeBlack 1:8465801be23f 171
NegativeBlack 1:8465801be23f 172 bool
NegativeBlack 1:8465801be23f 173 SHT15::readRegister(cmd_list command) {
NegativeBlack 1:8465801be23f 174 while (this->ready == false) {
NegativeBlack 1:8465801be23f 175 continue;
NegativeBlack 1:8465801be23f 176 }
NegativeBlack 1:8465801be23f 177
NegativeBlack 1:8465801be23f 178 this->ready = false;
NegativeBlack 1:8465801be23f 179 this->i2c.start();
NegativeBlack 1:8465801be23f 180
NegativeBlack 1:8465801be23f 181 if (!this->i2c.write(command)) {
NegativeBlack 1:8465801be23f 182 this->i2c.stop();
NegativeBlack 1:8465801be23f 183 return false;
NegativeBlack 1:8465801be23f 184 }
NegativeBlack 1:8465801be23f 185
NegativeBlack 1:8465801be23f 186 switch (command) {
NegativeBlack 1:8465801be23f 187 case cmd_read_temperature: {
NegativeBlack 1:8465801be23f 188 if (!this->i2c.wait()) {
NegativeBlack 1:8465801be23f 189 this->i2c.stop();
NegativeBlack 1:8465801be23f 190 return false;
NegativeBlack 1:8465801be23f 191 }
NegativeBlack 1:8465801be23f 192
NegativeBlack 1:8465801be23f 193 this->temperature = this->i2c.read(1) << 8;
NegativeBlack 1:8465801be23f 194 this->temperature |= this->i2c.read(0);
NegativeBlack 1:8465801be23f 195 } break;
NegativeBlack 1:8465801be23f 196
NegativeBlack 1:8465801be23f 197 case cmd_read_humidity: {
NegativeBlack 1:8465801be23f 198 if (!this->i2c.wait()) {
NegativeBlack 1:8465801be23f 199 this->i2c.stop();
NegativeBlack 1:8465801be23f 200 return false;
NegativeBlack 1:8465801be23f 201 }
NegativeBlack 1:8465801be23f 202
NegativeBlack 1:8465801be23f 203 this->humidity = this->i2c.read(1) << 8;
NegativeBlack 1:8465801be23f 204 this->humidity |= this->i2c.read(0);
NegativeBlack 1:8465801be23f 205 } break;
NegativeBlack 1:8465801be23f 206
NegativeBlack 1:8465801be23f 207 case cmd_read_register: {
NegativeBlack 1:8465801be23f 208 this->status_register = this->i2c.read(0);
NegativeBlack 1:8465801be23f 209 } break;
NegativeBlack 1:8465801be23f 210 }
NegativeBlack 1:8465801be23f 211
NegativeBlack 1:8465801be23f 212 this->i2c.stop();
NegativeBlack 1:8465801be23f 213 this->ready = true;
NegativeBlack 1:8465801be23f 214
NegativeBlack 1:8465801be23f 215 return true;
NegativeBlack 1:8465801be23f 216 }
NegativeBlack 1:8465801be23f 217
NegativeBlack 1:8465801be23f 218 bool
NegativeBlack 1:8465801be23f 219 SHT15::getFlag(SHT15::flag_list flag) {
NegativeBlack 1:8465801be23f 220 return (this->status_register & flag) ? true : false;
NegativeBlack 1:8465801be23f 221 }
NegativeBlack 1:8465801be23f 222
NegativeBlack 1:8465801be23f 223 void
NegativeBlack 1:8465801be23f 224 SHT15::setFlag(SHT15::flag_list flag, bool value) {
NegativeBlack 1:8465801be23f 225 if (value) {
NegativeBlack 1:8465801be23f 226 this->status_register |= flag;
NegativeBlack 1:8465801be23f 227 } else {
NegativeBlack 1:8465801be23f 228 this->status_register &= ~flag;
NegativeBlack 1:8465801be23f 229 }
NegativeBlack 1:8465801be23f 230 }
NegativeBlack 1:8465801be23f 231 }
ppatierno 2:7505a67001b4 232
ppatierno 2:7505a67001b4 233 SHTx::SHT15 sensor(PTE25, PTE24);
ppatierno 2:7505a67001b4 234
ppatierno 2:7505a67001b4 235 extern "C" void SHT15_init(void) {
ppatierno 2:7505a67001b4 236
ppatierno 2:7505a67001b4 237 // Speed things up a bit.
ppatierno 2:7505a67001b4 238 sensor.setOTPReload(false);
ppatierno 2:7505a67001b4 239 sensor.setResolution(true);
ppatierno 2:7505a67001b4 240
ppatierno 2:7505a67001b4 241 // Temperature in celcius
ppatierno 2:7505a67001b4 242 sensor.setScale(false);
ppatierno 2:7505a67001b4 243
ppatierno 2:7505a67001b4 244 return;
ppatierno 2:7505a67001b4 245 }
ppatierno 2:7505a67001b4 246
ppatierno 2:7505a67001b4 247 extern "C" void SHT15_update(void) {
ppatierno 2:7505a67001b4 248
ppatierno 2:7505a67001b4 249 sensor.update();
ppatierno 2:7505a67001b4 250 return;
ppatierno 2:7505a67001b4 251 }
ppatierno 2:7505a67001b4 252
ppatierno 2:7505a67001b4 253 extern "C" float SHT15_getTemperature(void) {
ppatierno 2:7505a67001b4 254
ppatierno 2:7505a67001b4 255 // Temperature
ppatierno 2:7505a67001b4 256 return sensor.getTemperature();
ppatierno 2:7505a67001b4 257 }
ppatierno 2:7505a67001b4 258
ppatierno 2:7505a67001b4 259 extern "C" float SHT15_getHumidity(void) {
ppatierno 2:7505a67001b4 260
ppatierno 2:7505a67001b4 261 // Relative Humidity
ppatierno 2:7505a67001b4 262 return sensor.getHumidity();
ppatierno 2:7505a67001b4 263 }
ppatierno 2:7505a67001b4 264
ppatierno 2:7505a67001b4 265 extern "C" void SHT15_setScale(bool value) {
ppatierno 2:7505a67001b4 266 sensor.setScale(value);
ppatierno 2:7505a67001b4 267 }