frederic blanc / OneWire_II

MAX31850, DS18B20, DS2450, thermocouple

DS18X20.cpp@0:5d39f2521173, 2015-03-09 (annotated)

Committer:
fblanc
Date:
Mon Mar 09 11:55:54 2015 +0000
Revision:
0:5d39f2521173
MAX31850

Who changed what in which revision?

UserRevisionLine numberNew contents of line
fblanc 0:5d39f2521173 1 /**
fblanc 0:5d39f2521173 2 * @file DS18x20.c
fblanc 0:5d39f2521173 3 * @brief library of DS18X20 1-Wire digital thermometer (http://www.maxim-ic.com/datasheet/index.mvp/id/2812)
fblanc 0:5d39f2521173 4 * @author Maciej Rajtar (Published 10 May 2010 www.mbed.org)
fblanc 0:5d39f2521173 5 * @author Frederic BLANC (Published 01/03/2012 www.mbed.org)
fblanc 0:5d39f2521173 6 */
fblanc 0:5d39f2521173 7 #include "mbed.h"
fblanc 0:5d39f2521173 8 #include "onewire.h"
fblanc 0:5d39f2521173 9 #include "DS18X20.h"
fblanc 0:5d39f2521173 10 #include "crc8.h"
fblanc 0:5d39f2521173 11 #include "utils.h"
fblanc 0:5d39f2521173 12 //**********************************************************************************************************
fblanc 0:5d39f2521173 13 //* DS18X20_show_temp
fblanc 0:5d39f2521173 14 //**********************************************************************************************************
fblanc 0:5d39f2521173 15
fblanc 0:5d39f2521173 16 /**
fblanc 0:5d39f2521173 17 * @brief DS18X20_show_temp
fblanc 0:5d39f2521173 18 * @param [in] id[] = rom_code
fblanc 0:5d39f2521173 19 * @param [in] n number of id[n]
fblanc 0:5d39f2521173 20 * @param [out] text temp in degre celsius
fblanc 0:5d39f2521173 21
fblanc 0:5d39f2521173 22 * @date 20/06/2011
fblanc 0:5d39f2521173 23 */
fblanc 0:5d39f2521173 24 void DS18X20_show_temp(uint8_t subzero, uint8_t cel, uint8_t cel_frac_bits,char *text) {
fblanc 0:5d39f2521173 25 uint16_t decicelsius;
fblanc 0:5d39f2521173 26 char s[10];
fblanc 0:5d39f2521173 27 float temperature;
fblanc 0:5d39f2521173 28 sprintf(text,"");
fblanc 0:5d39f2521173 29 sprintf(s,"%s", (subzero)?"-":"");
fblanc 0:5d39f2521173 30 strcat(text,s);
fblanc 0:5d39f2521173 31 decicelsius = DS18X20_temp_to_decicel(subzero, cel, cel_frac_bits);
fblanc 0:5d39f2521173 32 temperature = decicelsius;
fblanc 0:5d39f2521173 33 temperature = temperature/10;
fblanc 0:5d39f2521173 34 sprintf(s,"%4.1f", temperature);
fblanc 0:5d39f2521173 35 strcat(text,s);
fblanc 0:5d39f2521173 36
fblanc 0:5d39f2521173 37 }
fblanc 0:5d39f2521173 38 /**
fblanc 0:5d39f2521173 39 * @brief DS18X20_show_temp
fblanc 0:5d39f2521173 40 * @param [in] id[] = rom_code
fblanc 0:5d39f2521173 41 * @param [in] n number of id[n]
fblanc 0:5d39f2521173 42 * @return temp in degre celsius
fblanc 0:5d39f2521173 43
fblanc 0:5d39f2521173 44 * @date 21/10/2011
fblanc 0:5d39f2521173 45 */
fblanc 0:5d39f2521173 46 float DS18X20_temp(uint8_t subzero, uint8_t cel, uint8_t cel_frac_bits) {
fblanc 0:5d39f2521173 47 return ((subzero)?-1:1)*DS18X20_temp_to_decicel(subzero, cel, cel_frac_bits)/10;
fblanc 0:5d39f2521173 48 }
fblanc 0:5d39f2521173 49 //**********************************************************************************************************
fblanc 0:5d39f2521173 50 //* DS18X20_get_power_status
fblanc 0:5d39f2521173 51 //**********************************************************************************************************
fblanc 0:5d39f2521173 52
fblanc 0:5d39f2521173 53 /**
fblanc 0:5d39f2521173 54 * @brief get power status of DS18x20
fblanc 0:5d39f2521173 55 * @param [in] id[] = rom_code
fblanc 0:5d39f2521173 56 * @return DS18X20_POWER_EXTERN or DS18X20_POWER_PARASITE
fblanc 0:5d39f2521173 57 * @date 20/06/2011
fblanc 0:5d39f2521173 58 */
fblanc 0:5d39f2521173 59 uint8_t DS18X20_get_power_status(uint8_t id[]) {
fblanc 0:5d39f2521173 60 uint8_t pstat;
fblanc 0:5d39f2521173 61 ow_reset();
fblanc 0:5d39f2521173 62 ow_command(DS18X20_READ_POWER_SUPPLY, id);
fblanc 0:5d39f2521173 63 pstat=ow_bit_io(1); // pstat 0=is parasite/ !=0 ext. powered
fblanc 0:5d39f2521173 64 ow_reset();
fblanc 0:5d39f2521173 65 return (pstat) ? DS18X20_POWER_EXTERN:DS18X20_POWER_PARASITE;
fblanc 0:5d39f2521173 66 }
fblanc 0:5d39f2521173 67
fblanc 0:5d39f2521173 68 /**
fblanc 0:5d39f2521173 69 * @brief get power status of DS18x20
fblanc 0:5d39f2521173 70 * @param [in] n num bus onewire
fblanc 0:5d39f2521173 71 * @param [in] id[] = rom_code
fblanc 0:5d39f2521173 72 * @return DS18X20_POWER_EXTERN or DS18X20_POWER_PARASITE
fblanc 0:5d39f2521173 73 * @date 6/09/2011
fblanc 0:5d39f2521173 74 */
fblanc 0:5d39f2521173 75 uint8_t DS18X20_get_power_status(uint8_t n,uint8_t id[]) {
fblanc 0:5d39f2521173 76 uint8_t pstat;
fblanc 0:5d39f2521173 77 ow_reset(n);
fblanc 0:5d39f2521173 78 ow_command(n,DS18X20_READ_POWER_SUPPLY, id);
fblanc 0:5d39f2521173 79 pstat=ow_bit_io(n,1); // pstat 0=is parasite/ !=0 ext. powered
fblanc 0:5d39f2521173 80 ow_reset(n);
fblanc 0:5d39f2521173 81 return (pstat) ? DS18X20_POWER_EXTERN:DS18X20_POWER_PARASITE;
fblanc 0:5d39f2521173 82 }
fblanc 0:5d39f2521173 83 //**********************************************************************************************************
fblanc 0:5d39f2521173 84 //* DS18X20_start_meas
fblanc 0:5d39f2521173 85 //**********************************************************************************************************
fblanc 0:5d39f2521173 86 /**
fblanc 0:5d39f2521173 87 * @brief reads temperature (scratchpad) of sensor with rom-code id
fblanc 0:5d39f2521173 88 output: subzero==1 if temp.<0, cel: full celsius, mcel: frac
fblanc 0:5d39f2521173 89 in millicelsius*0.1
fblanc 0:5d39f2521173 90 i.e.: subzero=1, cel=18, millicel=5000 = -18,5000&#65533;C
fblanc 0:5d39f2521173 91 * @param [in] n num bus onewire
fblanc 0:5d39f2521173 92 * @param [in] id[] = rom_code
fblanc 0:5d39f2521173 93 * @param [out] temperature
fblanc 0:5d39f2521173 94 * @return DS18X20_OK or DS18X20_ERROR_CRC
fblanc 0:5d39f2521173 95 * @date 07/12/2012
fblanc 0:5d39f2521173 96 */
fblanc 0:5d39f2521173 97 uint8_t DS18X20_read_meas(uint8_t n,uint8_t id[], float* temperature) {
fblanc 0:5d39f2521173 98 uint8_t i;
fblanc 0:5d39f2521173 99 uint8_t sp[DS18X20_SP_SIZE];
fblanc 0:5d39f2521173 100 uint8_t subzero;
fblanc 0:5d39f2521173 101 uint8_t cel;
fblanc 0:5d39f2521173 102 uint8_t cel_frac_bits;
fblanc 0:5d39f2521173 103
fblanc 0:5d39f2521173 104 ow_reset(n);
fblanc 0:5d39f2521173 105 ow_command(n,DS18X20_READ, id);
fblanc 0:5d39f2521173 106 for ( i=0 ; i< DS18X20_SP_SIZE; i++ )
fblanc 0:5d39f2521173 107 sp[i]=ow_byte_rd(n);
fblanc 0:5d39f2521173 108 if ( crc8( &sp[0], DS18X20_SP_SIZE ) ){
fblanc 0:5d39f2521173 109 if ((sp[DS18X20_SP_SIZE-1]==0xFF) && (sp[DS18X20_SP_SIZE-2]==0xFF))
fblanc 0:5d39f2521173 110 return OW_ERROR; // bus error
fblanc 0:5d39f2521173 111 return DS18X20_ERROR_CRC; // data error
fblanc 0:5d39f2521173 112 }
fblanc 0:5d39f2521173 113
fblanc 0:5d39f2521173 114 DS18X20_meas_to_cel(id[0], sp, &subzero, &cel, &cel_frac_bits);
fblanc 0:5d39f2521173 115 *temperature = cel_frac_bits*.0625;
fblanc 0:5d39f2521173 116 *temperature += cel;
fblanc 0:5d39f2521173 117 if (subzero)
fblanc 0:5d39f2521173 118 *temperature *= -1;
fblanc 0:5d39f2521173 119 return DS18X20_OK;
fblanc 0:5d39f2521173 120 }
fblanc 0:5d39f2521173 121 /**
fblanc 0:5d39f2521173 122 * @brief start measurement (CONVERT_T) for all sensors if input id==NULL
fblanc 0:5d39f2521173 123 or for single sensor. then id is the rom-code
fblanc 0:5d39f2521173 124 * @param [in] with_power_extern
fblanc 0:5d39f2521173 125 * @param [in] rom_code
fblanc 0:5d39f2521173 126 * @return DS18X20_OK or DS18X20_START_FAIL
fblanc 0:5d39f2521173 127 * @date 20/06/2011
fblanc 0:5d39f2521173 128 */
fblanc 0:5d39f2521173 129 uint8_t DS18X20_start_meas( uint8_t with_power_extern, uint8_t id[]) {
fblanc 0:5d39f2521173 130 ow_reset(); //**
fblanc 0:5d39f2521173 131 if ( ow_test_pin() ) { // only send if bus is "idle" = high
fblanc 0:5d39f2521173 132 ow_command( DS18X20_CONVERT_T, id );
fblanc 0:5d39f2521173 133 if (with_power_extern != DS18X20_POWER_EXTERN)
fblanc 0:5d39f2521173 134 ow_parasite_enable();
fblanc 0:5d39f2521173 135 return DS18X20_OK;
fblanc 0:5d39f2521173 136 }
fblanc 0:5d39f2521173 137 return DS18X20_START_FAIL;
fblanc 0:5d39f2521173 138
fblanc 0:5d39f2521173 139 }
fblanc 0:5d39f2521173 140 /**
fblanc 0:5d39f2521173 141 * @brief start measurement (CONVERT_T) for all sensors if input id==NULL
fblanc 0:5d39f2521173 142 or for single sensor. then id is the rom-code
fblanc 0:5d39f2521173 143 * @param [in] n num bus onewire
fblanc 0:5d39f2521173 144 * @param [in] with_power_extern
fblanc 0:5d39f2521173 145 * @param [in] rom_code
fblanc 0:5d39f2521173 146 * @return DS18X20_OK or DS18X20_START_FAIL
fblanc 0:5d39f2521173 147 * @date 06/09/2011
fblanc 0:5d39f2521173 148 */
fblanc 0:5d39f2521173 149 uint8_t DS18X20_start_meas(uint8_t n, uint8_t with_power_extern, uint8_t id[]) {
fblanc 0:5d39f2521173 150 ow_reset(n); //**
fblanc 0:5d39f2521173 151 if ( ow_test_pin(n) ) { // only send if bus is "idle" = high
fblanc 0:5d39f2521173 152 ow_command(n, DS18X20_CONVERT_T, id );
fblanc 0:5d39f2521173 153 if (with_power_extern != DS18X20_POWER_EXTERN)
fblanc 0:5d39f2521173 154 ow_parasite_enable(n);
fblanc 0:5d39f2521173 155 return DS18X20_OK;
fblanc 0:5d39f2521173 156 }
fblanc 0:5d39f2521173 157 return DS18X20_START_FAIL;
fblanc 0:5d39f2521173 158
fblanc 0:5d39f2521173 159 }
fblanc 0:5d39f2521173 160 //**********************************************************************************************************
fblanc 0:5d39f2521173 161 //* DS18X20_read_meas
fblanc 0:5d39f2521173 162 //**********************************************************************************************************
fblanc 0:5d39f2521173 163
fblanc 0:5d39f2521173 164 /**
fblanc 0:5d39f2521173 165 * @brief reads temperature (scratchpad) of sensor with rom-code id
fblanc 0:5d39f2521173 166 output: subzero==1 if temp.<0, cel: full celsius, mcel: frac
fblanc 0:5d39f2521173 167 in millicelsius*0.1
fblanc 0:5d39f2521173 168 i.e.: subzero=1, cel=18, millicel=5000 = -18,5000&#65533;C
fblanc 0:5d39f2521173 169 * @param [in] id[] = rom_code
fblanc 0:5d39f2521173 170 * @param [out] subzero
fblanc 0:5d39f2521173 171 * @param [out] cel
fblanc 0:5d39f2521173 172 * @param [out] cel_frac_bits
fblanc 0:5d39f2521173 173 * @return DS18X20_OK or DS18X20_ERROR_CRC
fblanc 0:5d39f2521173 174 * @date 20/06/2011
fblanc 0:5d39f2521173 175 */
fblanc 0:5d39f2521173 176 uint8_t DS18X20_read_meas(uint8_t id[], uint8_t *subzero,
fblanc 0:5d39f2521173 177 uint8_t *cel, uint8_t *cel_frac_bits) {
fblanc 0:5d39f2521173 178 uint8_t i;
fblanc 0:5d39f2521173 179 uint8_t sp[DS18X20_SP_SIZE];
fblanc 0:5d39f2521173 180
fblanc 0:5d39f2521173 181 ow_reset();
fblanc 0:5d39f2521173 182 ow_command(DS18X20_READ, id);
fblanc 0:5d39f2521173 183 for ( i=0 ; i< DS18X20_SP_SIZE; i++ )
fblanc 0:5d39f2521173 184 sp[i]=ow_byte_rd();
fblanc 0:5d39f2521173 185 if ( crc8( &sp[0], DS18X20_SP_SIZE ) ){
fblanc 0:5d39f2521173 186 if ((sp[DS18X20_SP_SIZE-1]==0xFF) && (sp[DS18X20_SP_SIZE-2]==0xFF))
fblanc 0:5d39f2521173 187 return OW_ERROR; // bus error
fblanc 0:5d39f2521173 188 return DS18X20_ERROR_CRC; // data error
fblanc 0:5d39f2521173 189 }
fblanc 0:5d39f2521173 190
fblanc 0:5d39f2521173 191 DS18X20_meas_to_cel(id[0], sp, subzero, cel, cel_frac_bits);
fblanc 0:5d39f2521173 192 return DS18X20_OK;
fblanc 0:5d39f2521173 193 }
fblanc 0:5d39f2521173 194 /**
fblanc 0:5d39f2521173 195 * @brief reads temperature (scratchpad) of sensor with rom-code id
fblanc 0:5d39f2521173 196 output: subzero==1 if temp.<0, cel: full celsius, mcel: frac
fblanc 0:5d39f2521173 197 in millicelsius*0.1
fblanc 0:5d39f2521173 198 i.e.: subzero=1, cel=18, millicel=5000 = -18,5000&#65533;C
fblanc 0:5d39f2521173 199 * @param [in] n num bus onewire
fblanc 0:5d39f2521173 200 * @param [in] id[] = rom_code
fblanc 0:5d39f2521173 201 * @param [out] subzero
fblanc 0:5d39f2521173 202 * @param [out] cel
fblanc 0:5d39f2521173 203 * @param [out] cel_frac_bits
fblanc 0:5d39f2521173 204 * @return DS18X20_OK or DS18X20_ERROR_CRC
fblanc 0:5d39f2521173 205 * @date 06/09/2011
fblanc 0:5d39f2521173 206 */
fblanc 0:5d39f2521173 207 uint8_t DS18X20_read_meas(uint8_t n,uint8_t id[], uint8_t *subzero,
fblanc 0:5d39f2521173 208 uint8_t *cel, uint8_t *cel_frac_bits) {
fblanc 0:5d39f2521173 209 uint8_t i;
fblanc 0:5d39f2521173 210 uint8_t sp[DS18X20_SP_SIZE];
fblanc 0:5d39f2521173 211
fblanc 0:5d39f2521173 212 ow_reset(n);
fblanc 0:5d39f2521173 213 ow_command(n,DS18X20_READ, id);
fblanc 0:5d39f2521173 214 for ( i=0 ; i< DS18X20_SP_SIZE; i++ )
fblanc 0:5d39f2521173 215 sp[i]=ow_byte_rd(n);
fblanc 0:5d39f2521173 216 if ( crc8( &sp[0], DS18X20_SP_SIZE ) ){
fblanc 0:5d39f2521173 217 if ((sp[DS18X20_SP_SIZE-1]==0xFF) && (sp[DS18X20_SP_SIZE-2]==0xFF))
fblanc 0:5d39f2521173 218 return OW_ERROR; // bus error
fblanc 0:5d39f2521173 219 return DS18X20_ERROR_CRC; // data error
fblanc 0:5d39f2521173 220 }
fblanc 0:5d39f2521173 221
fblanc 0:5d39f2521173 222 DS18X20_meas_to_cel(id[0], sp, subzero, cel, cel_frac_bits);
fblanc 0:5d39f2521173 223 return DS18X20_OK;
fblanc 0:5d39f2521173 224 }
fblanc 0:5d39f2521173 225 /**
fblanc 0:5d39f2521173 226 * @brief convert raw value from DS18x20 to Celsius
fblanc 0:5d39f2521173 227 input is:
fblanc 0:5d39f2521173 228 - familycode fc (0x10/0x28 see header)
fblanc 0:5d39f2521173 229 - scratchpad-buffer
fblanc 0:5d39f2521173 230 output is:
fblanc 0:5d39f2521173 231 - cel full celsius
fblanc 0:5d39f2521173 232 - fractions of celsius in millicelsius*(10^-1)/625 (the 4 LS-Bits)
fblanc 0:5d39f2521173 233 - subzero =0 positiv / 1 negativ
fblanc 0:5d39f2521173 234 always returns DS18X20_OK
fblanc 0:5d39f2521173 235 TODO invalid-values detection (but should be covered by CRC)
fblanc 0:5d39f2521173 236 * @param [in] fc
fblanc 0:5d39f2521173 237 * @param [in] sp
fblanc 0:5d39f2521173 238 * @param [out] subzero
fblanc 0:5d39f2521173 239 * @param [out] cel
fblanc 0:5d39f2521173 240 * @param [out] cel_frac_bits
fblanc 0:5d39f2521173 241 * @return DS18X20_OK
fblanc 0:5d39f2521173 242 * @date 20/06/2011
fblanc 0:5d39f2521173 243 */
fblanc 0:5d39f2521173 244 uint8_t DS18X20_meas_to_cel( uint8_t fc, uint8_t *sp,
fblanc 0:5d39f2521173 245 uint8_t* subzero, uint8_t* cel, uint8_t* cel_frac_bits) {
fblanc 0:5d39f2521173 246 uint16_t meas;
fblanc 0:5d39f2521173 247 uint8_t i;
fblanc 0:5d39f2521173 248
fblanc 0:5d39f2521173 249 meas = sp[0]; // LSB
fblanc 0:5d39f2521173 250 meas |= ((uint16_t)sp[1])<<8; // MSB
fblanc 0:5d39f2521173 251 //meas = 0xff5e; meas = 0xfe6f;
fblanc 0:5d39f2521173 252
fblanc 0:5d39f2521173 253 // only work on 12bit-base
fblanc 0:5d39f2521173 254 if ( fc == DS18S20_ID ) { // 9 -> 12 bit if 18S20
fblanc 0:5d39f2521173 255 /* Extended measurements for DS18S20 contributed by Carsten Foss */
fblanc 0:5d39f2521173 256 meas &= (uint16_t) 0xfffe; // Discard LSB , needed for later extended precicion calc
fblanc 0:5d39f2521173 257 meas <<= 3; // Convert to 12-bit , now degrees are in 1/16 degrees units
fblanc 0:5d39f2521173 258 meas += (16 - sp[6]) - 4; // Add the compensation , and remember to subtract 0.25 degree (4/16)
fblanc 0:5d39f2521173 259 }
fblanc 0:5d39f2521173 260
fblanc 0:5d39f2521173 261 // check for negative
fblanc 0:5d39f2521173 262 if ( meas & 0x8000 ) {
fblanc 0:5d39f2521173 263 *subzero=1; // mark negative
fblanc 0:5d39f2521173 264 meas ^= 0xffff; // convert to positive => (twos complement)++
fblanc 0:5d39f2521173 265 meas++;
fblanc 0:5d39f2521173 266 } else *subzero=0;
fblanc 0:5d39f2521173 267
fblanc 0:5d39f2521173 268 // clear undefined bits for B != 12bit
fblanc 0:5d39f2521173 269 if ( fc == DS18B20_ID ) { // check resolution 18B20
fblanc 0:5d39f2521173 270 i = sp[DS18B20_CONF_REG];
fblanc 0:5d39f2521173 271 if ( (i & DS18B20_12_BIT) == DS18B20_12_BIT ) ;
fblanc 0:5d39f2521173 272 else if ( (i & DS18B20_11_BIT) == DS18B20_11_BIT )
fblanc 0:5d39f2521173 273 meas &= ~(DS18B20_11_BIT_UNDF);
fblanc 0:5d39f2521173 274 else if ( (i & DS18B20_10_BIT) == DS18B20_10_BIT )
fblanc 0:5d39f2521173 275 meas &= ~(DS18B20_10_BIT_UNDF);
fblanc 0:5d39f2521173 276 else { // if ( (i & DS18B20_9_BIT) == DS18B20_9_BIT ) {
fblanc 0:5d39f2521173 277 meas &= ~(DS18B20_9_BIT_UNDF);
fblanc 0:5d39f2521173 278 }
fblanc 0:5d39f2521173 279 }
fblanc 0:5d39f2521173 280
fblanc 0:5d39f2521173 281 *cel = (uint8_t)(meas >> 4);
fblanc 0:5d39f2521173 282 *cel_frac_bits = (uint8_t)(meas & 0x000F);
fblanc 0:5d39f2521173 283
fblanc 0:5d39f2521173 284 return DS18X20_OK;
fblanc 0:5d39f2521173 285 }
fblanc 0:5d39f2521173 286
fblanc 0:5d39f2521173 287 /**
fblanc 0:5d39f2521173 288 * @brief converts to decicelsius
fblanc 0:5d39f2521173 289 input is ouput from meas_to_cel
fblanc 0:5d39f2521173 290 i.e.: sz=0, c=28, frac=15 returns 289 (=28.9&#65533;C)
fblanc 0:5d39f2521173 291 0 0 0
fblanc 0:5d39f2521173 292 1 625 625 1
fblanc 0:5d39f2521173 293 2 1250 250
fblanc 0:5d39f2521173 294 3 1875 875 3
fblanc 0:5d39f2521173 295 4 2500 500 4
fblanc 0:5d39f2521173 296 5 3125 125
fblanc 0:5d39f2521173 297 6 3750 750 6
fblanc 0:5d39f2521173 298 7 4375 375
fblanc 0:5d39f2521173 299 8 5000 0
fblanc 0:5d39f2521173 300 9 5625 625 9
fblanc 0:5d39f2521173 301 10 6250 250
fblanc 0:5d39f2521173 302 11 6875 875 11
fblanc 0:5d39f2521173 303 12 7500 500 12
fblanc 0:5d39f2521173 304 13 8125 125
fblanc 0:5d39f2521173 305 14 8750 750 14
fblanc 0:5d39f2521173 306 15 9375 375
fblanc 0:5d39f2521173 307 * @param [in] subzero
fblanc 0:5d39f2521173 308 * @param [in] cel
fblanc 0:5d39f2521173 309 * @param [in] cel_frac_bits
fblanc 0:5d39f2521173 310 * @return absolute value of temperatur in decicelsius
fblanc 0:5d39f2521173 311 * @date 20/06/2011
fblanc 0:5d39f2521173 312 */
fblanc 0:5d39f2521173 313 uint16_t DS18X20_temp_to_decicel(uint8_t subzero, uint8_t cel,
fblanc 0:5d39f2521173 314 uint8_t cel_frac_bits) {
fblanc 0:5d39f2521173 315 uint16_t h;
fblanc 0:5d39f2521173 316 uint8_t i;
fblanc 0:5d39f2521173 317 uint8_t need_rounding[] = { 1, 3, 4, 6, 9, 11, 12, 14 };
fblanc 0:5d39f2521173 318
fblanc 0:5d39f2521173 319 h = cel_frac_bits*DS18X20_FRACCONV/1000;
fblanc 0:5d39f2521173 320 h += cel*10;
fblanc 0:5d39f2521173 321 if (!subzero) {
fblanc 0:5d39f2521173 322 for (i=0; i<sizeof(need_rounding); i++) {
fblanc 0:5d39f2521173 323 if ( cel_frac_bits == need_rounding[i] ) {
fblanc 0:5d39f2521173 324 h++;
fblanc 0:5d39f2521173 325 break;
fblanc 0:5d39f2521173 326 }
fblanc 0:5d39f2521173 327 }
fblanc 0:5d39f2521173 328 }
fblanc 0:5d39f2521173 329 return h;
fblanc 0:5d39f2521173 330 }
fblanc 0:5d39f2521173 331 /**
fblanc 0:5d39f2521173 332 * @brief compare temperature values (full celsius only)
fblanc 0:5d39f2521173 333 * @param [in] subzero1
fblanc 0:5d39f2521173 334 * @param [in] cel1
fblanc 0:5d39f2521173 335 * @param [in] subzero2
fblanc 0:5d39f2521173 336 * @param [in] cel2
fblanc 0:5d39f2521173 337 * @return -1 if param-pair1 < param-pair2
fblanc 0:5d39f2521173 338 0 if ==
fblanc 0:5d39f2521173 339 1 if >
fblanc 0:5d39f2521173 340 * @date 20/06/2011
fblanc 0:5d39f2521173 341 */
fblanc 0:5d39f2521173 342 int8_t DS18X20_temp_cmp(uint8_t subzero1, uint16_t cel1,
fblanc 0:5d39f2521173 343 uint8_t subzero2, uint16_t cel2) {
fblanc 0:5d39f2521173 344 int16_t t1 = (subzero1) ? (cel1*(-1)) : (cel1);
fblanc 0:5d39f2521173 345 int16_t t2 = (subzero2) ? (cel2*(-1)) : (cel2);
fblanc 0:5d39f2521173 346
fblanc 0:5d39f2521173 347 if (t1<t2) return -1;
fblanc 0:5d39f2521173 348 if (t1>t2) return 1;
fblanc 0:5d39f2521173 349 return 0;
fblanc 0:5d39f2521173 350 }