bme280.c (7452B)
1 /* Copyright 2021 rate 2 * 3 * This program is free software: you can redistribute it and/or modify 4 * it under the terms of the GNU General Public License as published by 5 * the Free Software Foundation, either version 2 of the License, or 6 * (at your option) any later version. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 #include <stdint.h> 17 #include "bme280.h" 18 #include "i2c_master.h" 19 20 #define BME280_ADDRESS (0x76<<1) 21 22 #define BME280_REG_CALIB00 (0x88) 23 #define BME280_REG_CALIB25 (0xA1) 24 #define BME280_REG_CALIB26 (0xE1) 25 #define BME280_REG_CTRL_HUM (0xF2) 26 #define BME280_REG_CTRL_MEAS (0xF4) 27 #define BME280_REG_CONFIG (0xF5) 28 #define BME280_REG_PRESS_MSB (0xf7) 29 30 #define I2C_BME280_TIMEOUT (20) 31 32 /* BME280 configurator values */ 33 /* [2:0] Humidity oversampling 34 * 000 Skipped 35 * 001 oversampling x1 36 * 010 oversampling x2 37 * 011 oversampling x4 38 * 100 oversampling x8 39 * 101,others oversampling x16 40 */ 41 #define BME280_CTRL_HUM_VAL (0x01) 42 43 44 /* [7:5] Pressure oversampling 45 * 000 Skipped 46 * 001 oversampling x1 47 * 010 oversampling x2 48 * 011 oversampling x4 49 * 100 oversampling x8 50 * 101,others oversampling x16 51 * [4:2] Temperature oversampling 52 * 000 Skipped 53 * 001 oversampling x1 54 * 010 oversampling x2 55 * 011 oversampling x4 56 * 100 oversampling x8 57 * 101,others oversampling x16 58 * [1:0] Mode 59 * 00 Sleep mode 60 * 11 Normal mode 61 */ 62 #define BME280_CTRL_MEAS_VAL (0x27) 63 64 /* [7:5] t_standby[ms] 65 * 000 0.5 66 * 001 62.5 67 * 010 125 68 * 011 250 69 * 100 500 70 * 101 1000 71 * 110 10 72 * 111 20 73 * [4:2] Filter corefficient 74 * 000 Filter off 75 * 001 2 76 * 010 4 77 * 011 8 78 * 100,others 16 79 * [0] SPI interface 80 * 0 4-wire 81 * 1 3-wire 82 */ 83 #define BME280_CONFIG_VAL (0xA0) 84 85 static void readTrim(void); 86 static void readData(void); 87 static int32_t calibration_T(int32_t adc_T); 88 static uint32_t calibration_P(int32_t adc_P); 89 static uint32_t calibration_H(int32_t adc_H); 90 91 static uint32_t hum_raw,temp_raw,pres_raw; 92 static uint16_t dig_T1; 93 static int16_t dig_T2, dig_T3; 94 static uint16_t dig_P1; 95 static int16_t dig_P2, dig_P3, dig_P4, dig_P5, dig_P6, dig_P7, dig_P8, dig_P9; 96 static uint8_t dig_H1, dig_H3; 97 static int16_t dig_H2, dig_H4, dig_H5; 98 static int8_t dig_H6; 99 static int32_t t_fine; 100 101 /* Private */ 102 static void readTrim(void) { 103 uint8_t data[32]; 104 105 i2c_read_register(BME280_ADDRESS, BME280_REG_CALIB00, &data[0], 24, I2C_BME280_TIMEOUT); 106 i2c_read_register(BME280_ADDRESS, BME280_REG_CALIB25, &data[25], 1, I2C_BME280_TIMEOUT); 107 i2c_read_register(BME280_ADDRESS, BME280_REG_CALIB26, &data[25], 7, I2C_BME280_TIMEOUT); 108 109 dig_T1 = (data[1] << 8) | data[0]; 110 dig_T2 = (data[3] << 8) | data[2]; 111 dig_T3 = (data[5] << 8) | data[4]; 112 dig_P1 = (data[7] << 8) | data[6]; 113 dig_P2 = (data[9] << 8) | data[8]; 114 dig_P3 = (data[11]<< 8) | data[10]; 115 dig_P4 = (data[13]<< 8) | data[12]; 116 dig_P5 = (data[15]<< 8) | data[14]; 117 dig_P6 = (data[17]<< 8) | data[16]; 118 dig_P7 = (data[19]<< 8) | data[18]; 119 dig_P8 = (data[21]<< 8) | data[20]; 120 dig_P9 = (data[23]<< 8) | data[22]; 121 dig_H1 = data[24]; 122 dig_H2 = (data[26]<< 8) | data[25]; 123 dig_H3 = data[27]; 124 dig_H4 = (data[28]<< 4) | (0x0F & data[29]); 125 dig_H5 = (data[30] << 4) | ((data[29] >> 4) & 0x0F); 126 dig_H6 = data[31]; 127 128 return; 129 } 130 131 static void readData(void) { 132 uint8_t data[8]; 133 134 i2c_read_register(BME280_ADDRESS, 0xF7, &data[0], 8, I2C_BME280_TIMEOUT); 135 136 pres_raw = data[0]; 137 pres_raw = (pres_raw<<8) | data[1]; 138 pres_raw = (pres_raw<<4) | (data[2] >> 4); 139 140 temp_raw = data[3]; 141 temp_raw = (temp_raw<<8) | data[4]; 142 temp_raw = (temp_raw<<4) | (data[5] >> 4); 143 144 hum_raw = data[6]; 145 hum_raw = (hum_raw << 8) | data[7]; 146 147 return; 148 } 149 150 static int32_t calibration_T(int32_t adc_T) { 151 int32_t var1, var2, T; 152 var1 = ((((adc_T >> 3) - ((int32_t)dig_T1<<1))) * ((int32_t)dig_T2)) >> 11; 153 var2 = (((((adc_T >> 4) - ((int32_t)dig_T1)) * ((adc_T>>4) - ((int32_t)dig_T1))) >> 12) * ((int32_t)dig_T3)) >> 14; 154 155 t_fine = var1 + var2; 156 T = (t_fine * 5 + 128) >> 8; 157 158 return T; 159 } 160 161 static uint32_t calibration_P(int32_t adc_P) { 162 int32_t var1, var2; 163 uint32_t P; 164 165 var1 = (((int32_t)t_fine)>>1) - (int32_t)64000; 166 var2 = (((var1>>2) * (var1>>2)) >> 11) * ((int32_t)dig_P6); 167 var2 = var2 + ((var1*((int32_t)dig_P5))<<1); 168 var2 = (var2>>2)+(((int32_t)dig_P4)<<16); 169 var1 = (((dig_P3 * (((var1>>2)*(var1>>2)) >> 13)) >>3) + ((((int32_t)dig_P2) * var1)>>1))>>18; 170 var1 = ((((32768+var1))*((int32_t)dig_P1))>>15); 171 if (var1 == 0) { 172 return 0; 173 } 174 P = (((uint32_t)(((int32_t)1048576)-adc_P)-(var2>>12)))*3125; 175 if( P < 0x80000000 ) { 176 P = (P << 1) / ((uint32_t) var1); 177 } else { 178 P = (P / (uint32_t)var1) * 2; 179 } 180 var1 = (((int32_t)dig_P9) * ((int32_t)(((P>>3) * (P>>3))>>13)))>>12; 181 var2 = (((int32_t)(P>>2)) * ((int32_t)dig_P8))>>13; 182 P = (uint32_t)((int32_t)P + ((var1 + var2 + dig_P7) >> 4)); 183 184 return P; 185 } 186 187 static uint32_t calibration_H(int32_t adc_H) { 188 int32_t v_x1; 189 190 v_x1 = (t_fine - ((int32_t)76800)); 191 v_x1 = (((((adc_H << 14) -(((int32_t)dig_H4) << 20) - (((int32_t)dig_H5) * v_x1)) + 192 ((int32_t)16384)) >> 15) * (((((((v_x1 * ((int32_t)dig_H6)) >> 10) * 193 (((v_x1 * ((int32_t)dig_H3)) >> 11) + ((int32_t) 32768))) >> 10) + (( int32_t)2097152)) * 194 ((int32_t) dig_H2) + 8192) >> 14)); 195 v_x1 = (v_x1 - (((((v_x1 >> 15) * (v_x1 >> 15)) >> 7) * ((int32_t)dig_H1)) >> 4)); 196 v_x1 = (v_x1 < 0 ? 0 : v_x1); 197 v_x1 = (v_x1 > 419430400 ? 419430400 : v_x1); 198 199 return (uint32_t)(v_x1 >> 12); 200 } 201 202 /* Public */ 203 void bme280_init(void) { 204 uint8_t ctrl_hum_reg; 205 uint8_t ctrl_meas_reg; 206 uint8_t config_reg; 207 208 ctrl_hum_reg = BME280_CTRL_HUM_VAL; 209 ctrl_meas_reg = BME280_CTRL_MEAS_VAL; 210 config_reg = BME280_CONFIG_VAL; 211 212 i2c_init(); 213 i2c_write_register(BME280_ADDRESS, BME280_REG_CTRL_HUM, &ctrl_hum_reg, 1, I2C_BME280_TIMEOUT); 214 i2c_write_register(BME280_ADDRESS, BME280_REG_CTRL_MEAS, &ctrl_meas_reg, 1, I2C_BME280_TIMEOUT); 215 i2c_write_register(BME280_ADDRESS, BME280_REG_CONFIG, &config_reg, 1, I2C_BME280_TIMEOUT); 216 readTrim(); 217 218 return; 219 } 220 221 void bme280_exec(void) { 222 readData(); 223 224 return; 225 } 226 227 double bme280_getTemp(void) { 228 double temp_act; 229 int32_t temp_cal; 230 231 temp_cal = calibration_T(temp_raw); 232 temp_act = (double)temp_cal / 100.0; 233 234 return temp_act; 235 } 236 237 double bme280_getPress(void) { 238 double press_act; 239 uint32_t press_cal; 240 241 press_cal = calibration_P(pres_raw); 242 press_act = (double)press_cal / 100.0; 243 244 return press_act; 245 } 246 247 double bme280_getHum(void) { 248 double hum_act; 249 uint32_t hum_cal; 250 251 hum_cal = calibration_H(hum_raw); 252 hum_act = (double)hum_cal / 1024.0; 253 254 return hum_act; 255 }