FG-HT / DS1820_new2

sad

Dependencies:   OneWire

DS1820.cpp@26:ab2080dd9e46, 20 months ago (annotated)

Committer:
brose
Date:
Thu Sep 15 12:35:33 2022 +0000
Revision:
26:ab2080dd9e46
Parent:
25:b78d40247b97 
small bugs

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 3:a250babd0a9f 1 /*
hudakz 3:a250babd0a9f 2 * Dallas' DS1820 family temperature sensor.
hudakz 3:a250babd0a9f 3 * This library depends on the OneWire library (Dallas' 1-Wire bus protocol implementation)
hudakz 6:518950e436be 4 * available at <http://developer.mbed.org/users/hudakz/code/OneWire/>
hudakz 3:a250babd0a9f 5 *
hudakz 3:a250babd0a9f 6 * Example of use:
hudakz 24:d683d826dccd 7 *
hudakz 20:98c261bcb399 8 * Single sensor.
hudakz 6:518950e436be 9 *
hudakz 20:98c261bcb399 10 * #include "mbed.h"
hudakz 20:98c261bcb399 11 * #include "DS1820.h"
hudakz 24:d683d826dccd 12 *
hudakz 20:98c261bcb399 13 * Serial pc(USBTX, USBRX);
hudakz 20:98c261bcb399 14 * DigitalOut led(LED1);
hudakz 20:98c261bcb399 15 * OneWire oneWire(D8); // substitute D8 with actual mbed pin name connected 1-wire bus
hudakz 20:98c261bcb399 16 * float temp = 0;
hudakz 20:98c261bcb399 17 * int result = 0;
hudakz 24:d683d826dccd 18 *
hudakz 20:98c261bcb399 19 * int main()
hudakz 20:98c261bcb399 20 * {
hudakz 20:98c261bcb399 21 * pc.printf("\r\n--Starting--\r\n");
hudakz 20:98c261bcb399 22 * if (ds1820.begin()) {
hudakz 20:98c261bcb399 23 * while (1) {
hudakz 20:98c261bcb399 24 * ds1820.startConversion(); // start temperature conversion from analog to digital
hudakz 24:d683d826dccd 25 * ThisThread::sleep_for(1000ms);// let DS1820 complete the temperature conversion
hudakz 24:d683d826dccd 26 * result = ds1820.read(temp); // read temperature from DS1820 and perform cyclic redundancy check (CRC)
hudakz 20:98c261bcb399 27 * switch (result) {
hudakz 24:d683d826dccd 28 * case 0: // no errors -> 'temp' contains the value of measured temperature
hudakz 20:98c261bcb399 29 * pc.printf("temp = %3.1f%cC\r\n", temp, 176);
hudakz 20:98c261bcb399 30 * break;
hudakz 24:d683d826dccd 31 *
hudakz 24:d683d826dccd 32 * case 1: // no sensor present -> 'temp' is not updated
hudakz 20:98c261bcb399 33 * pc.printf("no sensor present\n\r");
hudakz 20:98c261bcb399 34 * break;
hudakz 24:d683d826dccd 35 *
hudakz 24:d683d826dccd 36 * case 2: // CRC error -> 'temp' is not updated
hudakz 20:98c261bcb399 37 * pc.printf("CRC error\r\n");
hudakz 20:98c261bcb399 38 * }
hudakz 24:d683d826dccd 39 *
hudakz 20:98c261bcb399 40 * led = !led;
hudakz 20:98c261bcb399 41 * }
hudakz 20:98c261bcb399 42 * }
hudakz 20:98c261bcb399 43 * else
hudakz 20:98c261bcb399 44 * pc.printf("No DS1820 sensor found!\r\n");
hudakz 20:98c261bcb399 45 * }
hudakz 24:d683d826dccd 46 *
hudakz 24:d683d826dccd 47 *
hudakz 20:98c261bcb399 48 * More sensors connected to the same 1-wire bus.
hudakz 24:d683d826dccd 49 *
hudakz 20:98c261bcb399 50 * #include "mbed.h"
hudakz 20:98c261bcb399 51 * #include "DS1820.h"
hudakz 24:d683d826dccd 52 *
hudakz 20:98c261bcb399 53 * #define SENSORS_COUNT 64 // number of DS1820 sensors to be connected to the 1-wire bus (max 256)
hudakz 24:d683d826dccd 54 *
hudakz 20:98c261bcb399 55 * Serial pc(USBTX, USBRX);
hudakz 20:98c261bcb399 56 * DigitalOut led(LED1);
hudakz 20:98c261bcb399 57 * OneWire oneWire(D8); // substitute D8 with actual mbed pin name connected to the DS1820 data pin
hudakz 20:98c261bcb399 58 * DS1820* ds1820[SENSORS_COUNT];
hudakz 20:98c261bcb399 59 * int sensors_found = 0; // counts the actually found DS1820 sensors
hudakz 20:98c261bcb399 60 * float temp = 0;
hudakz 20:98c261bcb399 61 * int result = 0;
hudakz 24:d683d826dccd 62 *
hudakz 3:a250babd0a9f 63 * int main() {
hudakz 20:98c261bcb399 64 * int i = 0;
hudakz 24:d683d826dccd 65 *
hudakz 20:98c261bcb399 66 * pc.printf("\r\n Starting \r\n");
hudakz 20:98c261bcb399 67 * //Enumerate (i.e. detect) DS1820 sensors on the 1-wire bus
hudakz 20:98c261bcb399 68 * for(i = 0; i < SENSORS_COUNT; i++) {
hudakz 20:98c261bcb399 69 * ds1820[i] = new DS1820(&oneWire);
hudakz 20:98c261bcb399 70 * if(!ds1820[i]->begin()) {
hudakz 20:98c261bcb399 71 * delete ds1820[i];
hudakz 20:98c261bcb399 72 * break;
hudakz 20:98c261bcb399 73 * }
hudakz 20:98c261bcb399 74 * }
hudakz 24:d683d826dccd 75 *
hudakz 20:98c261bcb399 76 * sensors_found = i;
hudakz 24:d683d826dccd 77 *
hudakz 20:98c261bcb399 78 * if (sensors_found == 0) {
hudakz 20:98c261bcb399 79 * pc.printf("No DS1820 sensor found!\r\n");
hudakz 20:98c261bcb399 80 * return -1;
hudakz 20:98c261bcb399 81 * }
hudakz 20:98c261bcb399 82 * else
hudakz 20:98c261bcb399 83 * pc.printf("Found %d sensors.\r\n", sensors_found);
hudakz 24:d683d826dccd 84 *
hudakz 20:98c261bcb399 85 * while(1) {
hudakz 20:98c261bcb399 86 * pc.printf("-------------------\r\n");
hudakz 20:98c261bcb399 87 * for(i = 0; i < sensors_found; i++)
hudakz 24:d683d826dccd 88 * ds1820[i]->startConversion(); // start temperature conversion from analog to digital
hudakz 24:d683d826dccd 89 * ThisThread::sleep_for(1000ms); // let DS1820s complete the temperature conversion
hudakz 20:98c261bcb399 90 * for(int i = 0; i < sensors_found; i++) {
hudakz 20:98c261bcb399 91 * if(ds1820[i]->isPresent())
hudakz 20:98c261bcb399 92 * pc.printf("temp[%d] = %3.1f%cC\r\n", i, ds1820[i]->read(), 176); // read temperature
hudakz 20:98c261bcb399 93 * }
hudakz 20:98c261bcb399 94 * }
hudakz 3:a250babd0a9f 95 * }
hudakz 24:d683d826dccd 96 *
hudakz 3:a250babd0a9f 97 */
hudakz 0:433af64321d5 98 #include "DS1820.h"
hudakz 0:433af64321d5 99
brose 25:b78d40247b97 100 //u#define DEBUG 1
hudakz 20:98c261bcb399 101
hudakz 20:98c261bcb399 102 //* Initializing static members
hudakz 24:d683d826dccd 103 uint8_t DS1820:: _lastAddr[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
hudakz 24:d683d826dccd 104
hudakz 20:98c261bcb399 105 /**
hudakz 20:98c261bcb399 106 * @brief Constructs a generic DS1820 sensor
hudakz 20:98c261bcb399 107 * @note begin() must be called to detect and initialize the actual model
hudakz 24:d683d826dccd 108 * @param gpioPin: Name of the GPIO pin
hudakz 20:98c261bcb399 109 * @retval
hudakz 20:98c261bcb399 110 */
hudakz 24:d683d826dccd 111 DS1820::DS1820(PinName gpioPin, int samplePoint_us /*=13*/ )
hudakz 24:d683d826dccd 112 {
hudakz 24:d683d826dccd 113 _oneWire = new OneWire(gpioPin, samplePoint_us);
hudakz 24:d683d826dccd 114 _present = false;
hudakz 24:d683d826dccd 115 _model_s = false;
hudakz 24:d683d826dccd 116 }
hudakz 24:d683d826dccd 117
hudakz 24:d683d826dccd 118 /**
hudakz 24:d683d826dccd 119 * @brief Constructs a generic DS1820 sensor
hudakz 24:d683d826dccd 120 * @note begin() must be called to detect and initialize the actual model
hudakz 24:d683d826dccd 121 * @param txPin: UART's Tx pin
hudakz 24:d683d826dccd 122 * @param rxPin: UART's Rx pin
hudakz 24:d683d826dccd 123 * @retval
hudakz 24:d683d826dccd 124 */
hudakz 24:d683d826dccd 125 DS1820::DS1820(PinName txPin, PinName rxPin)
hudakz 24:d683d826dccd 126 {
hudakz 24:d683d826dccd 127 _oneWire = new OneWire(txPin, rxPin);
hudakz 24:d683d826dccd 128 _present = false;
hudakz 24:d683d826dccd 129 _model_s = false;
hudakz 20:98c261bcb399 130 }
hudakz 0:433af64321d5 131
hudakz 0:433af64321d5 132 /**
hudakz 0:433af64321d5 133 * @brief Constructs a generic DS1820 sensor
hudakz 0:433af64321d5 134 * @note begin() must be called to detect and initialize the actual model
hudakz 3:a250babd0a9f 135 * @param pin: Name of data pin
hudakz 0:433af64321d5 136 * @retval
hudakz 0:433af64321d5 137 */
hudakz 24:d683d826dccd 138 DS1820::DS1820(OneWire* oneWire) :
hudakz 24:d683d826dccd 139 _oneWire(oneWire)
hudakz 24:d683d826dccd 140 {
hudakz 24:d683d826dccd 141 _present = false;
hudakz 24:d683d826dccd 142 _model_s = false;
hudakz 0:433af64321d5 143 }
hudakz 0:433af64321d5 144
hudakz 0:433af64321d5 145 /**
hudakz 0:433af64321d5 146 * @brief Detects and initializes the actual DS1820 model
hudakz 0:433af64321d5 147 * @note
hudakz 0:433af64321d5 148 * @param
hudakz 0:433af64321d5 149 * @retval true: if a DS1820 family sensor was detected and initialized
hudakz 0:433af64321d5 150 false: otherwise
hudakz 0:433af64321d5 151 */
hudakz 24:d683d826dccd 152 bool DS1820::begin(void)
hudakz 24:d683d826dccd 153 {
hudakz 20:98c261bcb399 154 #if DEBUG
hudakz 20:98c261bcb399 155 printf("lastAddr =");
hudakz 24:d683d826dccd 156 for (uint8_t i = 0; i < 8; i++) {
brose 25:b78d40247b97 157 printf(" %x", _lastAddr[i]);
hudakz 20:98c261bcb399 158 }
hudakz 24:d683d826dccd 159
hudakz 20:98c261bcb399 160 printf("\r\n");
hudakz 20:98c261bcb399 161 #endif
hudakz 24:d683d826dccd 162 if (!_oneWire->search(_lastAddr))
hudakz 24:d683d826dccd 163 {
hudakz 0:433af64321d5 164 #if DEBUG
hudakz 17:9ff584b9809f 165 printf("No addresses.\r\n");
hudakz 0:433af64321d5 166 #endif
hudakz 24:d683d826dccd 167 _oneWire->reset_search();
hudakz 24:d683d826dccd 168 #if MBED_MAJOR_VERSION == 2
hudakz 24:d683d826dccd 169 wait_ms(250);
hudakz 24:d683d826dccd 170 #else
hudakz 24:d683d826dccd 171 ThisThread::sleep_for(250ms);
brose 26:ab2080dd9e46 172 //wait_ms(250);
hudakz 24:d683d826dccd 173 #endif
hudakz 0:433af64321d5 174 return false;
hudakz 0:433af64321d5 175 }
hudakz 24:d683d826dccd 176
hudakz 20:98c261bcb399 177 for (int i = 0; i < 8; i++)
hudakz 24:d683d826dccd 178 _addr[i] = _lastAddr[i];
hudakz 0:433af64321d5 179
hudakz 0:433af64321d5 180 #if DEBUG
hudakz 17:9ff584b9809f 181 printf("ROM =");
hudakz 24:d683d826dccd 182 for (uint8_t i = 0; i < 8; i++) {
brose 25:b78d40247b97 183 printf(" %x", _addr[i]);
hudakz 0:433af64321d5 184 }
hudakz 24:d683d826dccd 185
hudakz 17:9ff584b9809f 186 printf("\r\n");
hudakz 0:433af64321d5 187 #endif
hudakz 24:d683d826dccd 188 if (OneWire::crc8(_addr, 7) == _addr[7]) {
hudakz 24:d683d826dccd 189 _present = true;
hudakz 0:433af64321d5 190
hudakz 0:433af64321d5 191 // the first ROM byte indicates which chip
hudakz 24:d683d826dccd 192 switch (_addr[0]) {
hudakz 24:d683d826dccd 193 case 0x10:
hudakz 24:d683d826dccd 194 _model_s = true;
hudakz 24:d683d826dccd 195 #if DEBUG
hudakz 24:d683d826dccd 196 printf("DS18S20 or old DS1820\r\n");
hudakz 24:d683d826dccd 197 #endif
hudakz 24:d683d826dccd 198 break;
hudakz 0:433af64321d5 199
hudakz 24:d683d826dccd 200 case 0x28:
hudakz 24:d683d826dccd 201 _model_s = false;
hudakz 24:d683d826dccd 202 #if DEBUG
hudakz 24:d683d826dccd 203 printf("DS18B20\r\n");
hudakz 24:d683d826dccd 204 #endif
hudakz 24:d683d826dccd 205 break;
hudakz 0:433af64321d5 206
hudakz 24:d683d826dccd 207 case 0x22:
hudakz 24:d683d826dccd 208 _model_s = false;
hudakz 24:d683d826dccd 209 #if DEBUG
hudakz 24:d683d826dccd 210 printf("DS1822\r\n");
hudakz 24:d683d826dccd 211 #endif
hudakz 24:d683d826dccd 212 break;
hudakz 0:433af64321d5 213
hudakz 24:d683d826dccd 214 default:
hudakz 24:d683d826dccd 215 _present = false;
hudakz 24:d683d826dccd 216 #if DEBUG
hudakz 24:d683d826dccd 217 printf("Device doesn't belong to the DS1820 family\r\n");
hudakz 24:d683d826dccd 218 #endif
hudakz 24:d683d826dccd 219 return false;
hudakz 0:433af64321d5 220 }
hudakz 24:d683d826dccd 221
hudakz 0:433af64321d5 222 return true;
hudakz 0:433af64321d5 223 }
hudakz 24:d683d826dccd 224 else
hudakz 24:d683d826dccd 225 {
hudakz 24:d683d826dccd 226 #if DEBUG
hudakz 17:9ff584b9809f 227 printf("Invalid CRC!\r\n");
hudakz 24:d683d826dccd 228 #endif
hudakz 0:433af64321d5 229 return false;
hudakz 0:433af64321d5 230 }
hudakz 0:433af64321d5 231 }
hudakz 0:433af64321d5 232
hudakz 0:433af64321d5 233 /**
hudakz 8:8dfdd1603e4d 234 * @brief Informs about presence of a DS1820 sensor.
hudakz 8:8dfdd1603e4d 235 * @note begin() shall be called before using this function
hudakz 24:d683d826dccd 236 * if a generic DS1820 instance was created by the user.
hudakz 8:8dfdd1603e4d 237 * No need to call begin() for a specific DS1820 instance.
hudakz 8:8dfdd1603e4d 238 * @param
hudakz 8:8dfdd1603e4d 239 * @retval true: when a DS1820 sensor is present
hudakz 8:8dfdd1603e4d 240 * false: otherwise
hudakz 8:8dfdd1603e4d 241 */
hudakz 24:d683d826dccd 242 bool DS1820::isPresent(void)
hudakz 24:d683d826dccd 243 {
hudakz 24:d683d826dccd 244 return _present;
hudakz 8:8dfdd1603e4d 245 }
hudakz 8:8dfdd1603e4d 246
hudakz 8:8dfdd1603e4d 247 /**
hudakz 6:518950e436be 248 * @brief Sets temperature-to-digital conversion resolution.
hudakz 4:adf4e7972d73 249 * @note The configuration register allows the user to set the resolution
hudakz 6:518950e436be 250 * of the temperature-to-digital conversion to 9, 10, 11, or 12 bits.
hudakz 6:518950e436be 251 * Defaults to 12-bit resolution for DS18B20.
hudakz 6:518950e436be 252 * DS18S20 allows only 9-bit resolution.
hudakz 6:518950e436be 253 * @param res: Resolution of the temperature-to-digital conversion in bits.
hudakz 4:adf4e7972d73 254 * @retval
hudakz 4:adf4e7972d73 255 */
hudakz 24:d683d826dccd 256 void DS1820::setResolution(uint8_t res)
hudakz 24:d683d826dccd 257 {
hudakz 4:adf4e7972d73 258 // keep resolution within limits
hudakz 24:d683d826dccd 259
hudakz 24:d683d826dccd 260 if (res > 12)
hudakz 4:adf4e7972d73 261 res = 12;
hudakz 24:d683d826dccd 262 if (res < 9)
hudakz 24:d683d826dccd 263 res = 9;
hudakz 24:d683d826dccd 264 if (_model_s)
hudakz 4:adf4e7972d73 265 res = 9;
hudakz 24:d683d826dccd 266
hudakz 24:d683d826dccd 267 _oneWire->reset();
hudakz 24:d683d826dccd 268 _oneWire->select(_addr);
hudakz 24:d683d826dccd 269 _oneWire->write_byte(0xBE); // to read Scratchpad
hudakz 24:d683d826dccd 270 for (uint8_t i = 0; i < 9; i++) // read Scratchpad bytes
hudakz 24:d683d826dccd 271 _data[i] = _oneWire->read_byte();
hudakz 4:adf4e7972d73 272
hudakz 24:d683d826dccd 273 _data[4] |= (res - 9) << 5; // update configuration byte (set resolution)
hudakz 24:d683d826dccd 274 _oneWire->reset();
hudakz 24:d683d826dccd 275 _oneWire->select(_addr);
hudakz 24:d683d826dccd 276 _oneWire->write_byte(0x4E); // to write into Scratchpad
hudakz 24:d683d826dccd 277 for (uint8_t i = 2; i < 5; i++) // write three bytes (2nd, 3rd, 4th) into Scratchpad
hudakz 24:d683d826dccd 278 _oneWire->write_byte(_data[i]);
hudakz 4:adf4e7972d73 279 }
hudakz 4:adf4e7972d73 280
hudakz 4:adf4e7972d73 281 /**
hudakz 0:433af64321d5 282 * @brief Starts temperature conversion
hudakz 6:518950e436be 283 * @note The time to complete the converion depends on the selected resolution:
hudakz 6:518950e436be 284 * 9-bit resolution -> max conversion time = 93.75ms
hudakz 6:518950e436be 285 * 10-bit resolution -> max conversion time = 187.5ms
hudakz 6:518950e436be 286 * 11-bit resolution -> max conversion time = 375ms
hudakz 6:518950e436be 287 * 12-bit resolution -> max conversion time = 750ms
hudakz 0:433af64321d5 288 * @param
hudakz 0:433af64321d5 289 * @retval
hudakz 0:433af64321d5 290 */
hudakz 24:d683d826dccd 291 void DS1820::startConversion(void)
hudakz 24:d683d826dccd 292 {
hudakz 24:d683d826dccd 293 if (_present) {
hudakz 24:d683d826dccd 294 _oneWire->reset();
hudakz 24:d683d826dccd 295 _oneWire->select(_addr);
hudakz 24:d683d826dccd 296 _oneWire->write_byte(0x44); //start temperature conversion
hudakz 0:433af64321d5 297 }
hudakz 0:433af64321d5 298 }
hudakz 0:433af64321d5 299
hudakz 0:433af64321d5 300 /**
hudakz 6:518950e436be 301 * @brief Reads temperature from the chip's Scratchpad
hudakz 0:433af64321d5 302 * @note
hudakz 0:433af64321d5 303 * @param
hudakz 0:433af64321d5 304 * @retval Floating point temperature value
hudakz 0:433af64321d5 305 */
hudakz 24:d683d826dccd 306 float DS1820::read(void)
hudakz 24:d683d826dccd 307 {
hudakz 24:d683d826dccd 308 if (_present) {
hudakz 24:d683d826dccd 309 _oneWire->reset();
hudakz 24:d683d826dccd 310 _oneWire->select(_addr);
hudakz 24:d683d826dccd 311 _oneWire->write_byte(0xBE); // to read Scratchpad
hudakz 24:d683d826dccd 312 for (uint8_t i = 0; i < 9; i++) // reading scratchpad registers
hudakz 24:d683d826dccd 313 _data[i] = _oneWire->read_byte();
hudakz 0:433af64321d5 314
hudakz 6:518950e436be 315 // Convert the raw bytes to a 16-bit unsigned value
hudakz 24:d683d826dccd 316 uint16_t* p_word = reinterpret_cast < uint16_t * > (&_data[0]);
hudakz 0:433af64321d5 317
hudakz 0:433af64321d5 318 #if DEBUG
hudakz 17:9ff584b9809f 319 printf("raw = %#x\r\n", *p_word);
hudakz 24:d683d826dccd 320 #endif
hudakz 24:d683d826dccd 321 if (_model_s) {
hudakz 6:518950e436be 322 *p_word = *p_word << 3; // 9-bit resolution
hudakz 24:d683d826dccd 323 if (_data[7] == 0x10) {
hudakz 0:433af64321d5 324
hudakz 6:518950e436be 325 // "count remain" gives full 12-bit resolution
hudakz 24:d683d826dccd 326 *p_word = (*p_word & 0xFFF0) + 12 - _data[6];
hudakz 0:433af64321d5 327 }
hudakz 0:433af64321d5 328 }
hudakz 0:433af64321d5 329 else {
hudakz 24:d683d826dccd 330 uint8_t cfg = (_data[4] & 0x60); // default 12-bit resolution
hudakz 24:d683d826dccd 331
hudakz 4:adf4e7972d73 332 // at lower resolution, the low bits are undefined, so let's clear them
hudakz 24:d683d826dccd 333 if (cfg == 0x00)
hudakz 6:518950e436be 334 *p_word = *p_word &~7; // 9-bit resolution
hudakz 0:433af64321d5 335 else
hudakz 24:d683d826dccd 336 if (cfg == 0x20)
hudakz 6:518950e436be 337 *p_word = *p_word &~3; // 10-bit resolution
hudakz 0:433af64321d5 338 else
hudakz 24:d683d826dccd 339 if (cfg == 0x40)
hudakz 6:518950e436be 340 *p_word = *p_word &~1; // 11-bit resolution
hudakz 0:433af64321d5 341 }
hudakz 6:518950e436be 342
hudakz 6:518950e436be 343 // Convert the raw bytes to a 16-bit signed fixed point value :
hudakz 6:518950e436be 344 // 1 sign bit, 7 integer bits, 8 fractional bits (two’s compliment
hudakz 6:518950e436be 345 // and the LSB of the 16-bit binary number represents 1/256th of a unit).
hudakz 6:518950e436be 346 *p_word = *p_word << 4;
hudakz 24:d683d826dccd 347
hudakz 6:518950e436be 348 // Convert to floating point value
hudakz 6:518950e436be 349 return(toFloat(*p_word));
hudakz 0:433af64321d5 350 }
hudakz 0:433af64321d5 351 else
hudakz 0:433af64321d5 352 return 0;
hudakz 0:433af64321d5 353 }
hudakz 0:433af64321d5 354
hudakz 0:433af64321d5 355 /**
hudakz 13:b593a82ce790 356 * @brief Reads temperature from chip's scratchpad.
hudakz 13:b593a82ce790 357 * @note Verifies data integrity by calculating cyclic redundancy check (CRC).
hudakz 13:b593a82ce790 358 * If the calculated CRC dosn't match the one stored in chip's scratchpad register
hudakz 13:b593a82ce790 359 * the temperature variable is not updated and CRC error code is returned.
hudakz 13:b593a82ce790 360 * @param temp: The temperature variable to be updated by this routine.
hudakz 13:b593a82ce790 361 * (It's passed as reference to floating point.)
hudakz 13:b593a82ce790 362 * @retval error code:
hudakz 13:b593a82ce790 363 * 0 - no errors ('temp' contains the temperature measured)
hudakz 13:b593a82ce790 364 * 1 - sensor not present ('temp' is not updated)
hudakz 13:b593a82ce790 365 * 2 - CRC error ('temp' is not updated)
hudakz 13:b593a82ce790 366 */
hudakz 24:d683d826dccd 367 uint8_t DS1820::read(float& temp)
hudakz 24:d683d826dccd 368 {
hudakz 24:d683d826dccd 369 if (_present) {
hudakz 24:d683d826dccd 370 _oneWire->reset();
hudakz 24:d683d826dccd 371 _oneWire->select(_addr);
hudakz 24:d683d826dccd 372 _oneWire->write_byte(0xBE); // to read Scratchpad
hudakz 24:d683d826dccd 373 for (uint8_t i = 0; i < 9; i++) // reading scratchpad registers
hudakz 24:d683d826dccd 374 _data[i] = _oneWire->read_byte();
hudakz 13:b593a82ce790 375
hudakz 24:d683d826dccd 376 if (_oneWire->crc8(_data, 8) != _data[8]) // if calculated CRC does not match the stored one
hudakz 17:9ff584b9809f 377 {
hudakz 17:9ff584b9809f 378 #if DEBUG
hudakz 24:d683d826dccd 379 for (uint8_t i = 0; i < 9; i++)
brose 25:b78d40247b97 380 printf("data[%d]=0x%.2x\r\n", i, _data[i]);
hudakz 24:d683d826dccd 381 #endif
hudakz 13:b593a82ce790 382 return 2; // return with CRC error
hudakz 17:9ff584b9809f 383 }
hudakz 13:b593a82ce790 384
hudakz 13:b593a82ce790 385 // Convert the raw bytes to a 16bit unsigned value
hudakz 24:d683d826dccd 386 uint16_t* p_word = reinterpret_cast < uint16_t * > (&_data[0]);
hudakz 13:b593a82ce790 387
hudakz 13:b593a82ce790 388 #if DEBUG
hudakz 17:9ff584b9809f 389 printf("raw = %#x\r\n", *p_word);
hudakz 13:b593a82ce790 390 #endif
hudakz 24:d683d826dccd 391 if (_model_s) {
hudakz 24:d683d826dccd 392 *p_word = *p_word << 3; // 9 bit resolution, max conversion time = 750ms
hudakz 24:d683d826dccd 393 if (_data[7] == 0x10) {
hudakz 13:b593a82ce790 394
hudakz 13:b593a82ce790 395 // "count remain" gives full 12 bit resolution
hudakz 24:d683d826dccd 396 *p_word = (*p_word & 0xFFF0) + 12 - _data[6];
hudakz 13:b593a82ce790 397 }
hudakz 13:b593a82ce790 398
hudakz 13:b593a82ce790 399 // Convert the raw bytes to a 16bit signed fixed point value :
hudakz 13:b593a82ce790 400 // 1 sign bit, 7 integer bits, 8 fractional bits (two's compliment
hudakz 13:b593a82ce790 401 // and the LSB of the 16bit binary number represents 1/256th of a unit).
hudakz 13:b593a82ce790 402 *p_word = *p_word << 4;
hudakz 24:d683d826dccd 403
hudakz 13:b593a82ce790 404 // Convert to floating point value
hudakz 13:b593a82ce790 405 temp = toFloat(*p_word);
hudakz 24:d683d826dccd 406 return 0; // return with no errors
hudakz 13:b593a82ce790 407 }
hudakz 13:b593a82ce790 408 else {
hudakz 24:d683d826dccd 409 uint8_t cfg = (_data[4] & 0x60); // default 12bit resolution, max conversion time = 750ms
hudakz 13:b593a82ce790 410
hudakz 13:b593a82ce790 411 // at lower resolution, the low bits are undefined, so let's clear them
hudakz 24:d683d826dccd 412 if (cfg == 0x00)
hudakz 24:d683d826dccd 413 *p_word = *p_word &~7; // 9bit resolution, max conversion time = 93.75ms
hudakz 13:b593a82ce790 414 else
hudakz 24:d683d826dccd 415 if (cfg == 0x20)
hudakz 24:d683d826dccd 416 *p_word = *p_word &~3; // 10bit resolution, max conversion time = 187.5ms
hudakz 13:b593a82ce790 417 else
hudakz 24:d683d826dccd 418 if (cfg == 0x40)
hudakz 24:d683d826dccd 419 *p_word = *p_word &~1; // 11bit resolution, max conversion time = 375ms
hudakz 13:b593a82ce790 420
hudakz 13:b593a82ce790 421 // Convert the raw bytes to a 16bit signed fixed point value :
hudakz 14:b02fa18b294a 422 // 1 sign bit, 7 integer bits, 8 fractional bits (two's complement
hudakz 13:b593a82ce790 423 // and the LSB of the 16bit binary number represents 1/256th of a unit).
hudakz 13:b593a82ce790 424 *p_word = *p_word << 4;
hudakz 24:d683d826dccd 425
hudakz 13:b593a82ce790 426 // Convert to floating point value
hudakz 13:b593a82ce790 427 temp = toFloat(*p_word);
hudakz 24:d683d826dccd 428 return 0; // return with no errors
hudakz 13:b593a82ce790 429 }
hudakz 13:b593a82ce790 430 }
hudakz 13:b593a82ce790 431 else
hudakz 24:d683d826dccd 432 return 1; // error, sensor is not present
hudakz 13:b593a82ce790 433 }
hudakz 13:b593a82ce790 434
hudakz 13:b593a82ce790 435 /**
hudakz 6:518950e436be 436 * @brief Converts a 16-bit signed fixed point value to floating point value
hudakz 6:518950e436be 437 * @note The 16-bit unsigned integer represnts actually
hudakz 6:518950e436be 438 * a 16-bit signed fixed point value:
hudakz 14:b02fa18b294a 439 * 1 sign bit, 7 integer bits, 8 fractional bits (two’s complement
hudakz 24:d683d826dccd 440 * and the LSB of the 16-bit binary number represents 1/256th of a unit).
hudakz 6:518950e436be 441 * @param 16-bit unsigned integer
hudakz 4:adf4e7972d73 442 * @retval Floating point value
hudakz 0:433af64321d5 443 */
hudakz 24:d683d826dccd 444 float DS1820::toFloat(uint16_t word)
hudakz 24:d683d826dccd 445 {
hudakz 24:d683d826dccd 446 if (word & 0x8000)
hudakz 24:d683d826dccd 447 return(-float(uint16_t(~word + 1)) / 256.0f);
hudakz 0:433af64321d5 448 else
hudakz 24:d683d826dccd 449 return(float(word) / 256.0f);
hudakz 0:433af64321d5 450 }
brose 25:b78d40247b97 451
brose 25:b78d40247b97 452 // new from brose
brose 25:b78d40247b97 453 void DS1820::getAddress(char * b)
brose 25:b78d40247b97 454 {
brose 25:b78d40247b97 455 //char b[20]= {};
brose 25:b78d40247b97 456
brose 25:b78d40247b97 457 sprintf (b, "%hhx%hhx%hhx%hhx%hhx%hhx%hhx%hhx", _addr[0],_addr[1],_addr[2],_addr[3],_addr[4],_addr[5],_addr[6],_addr[7]);
brose 25:b78d40247b97 458 //printf(b);
brose 25:b78d40247b97 459
brose 25:b78d40247b97 460 }