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/* Copyright 2021 rate
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include "bme280.h"
#include "i2c_master.h"
#define BME280_ADDRESS (0x76<<1)
#define BME280_REG_CALIB00 (0x88)
#define BME280_REG_CALIB25 (0xA1)
#define BME280_REG_CALIB26 (0xE1)
#define BME280_REG_CTRL_HUM (0xF2)
#define BME280_REG_CTRL_MEAS (0xF4)
#define BME280_REG_CONFIG (0xF5)
#define BME280_REG_PRESS_MSB (0xf7)
#define I2C_BME280_TIMEOUT (20)
/* BME280 configurator values */
/* [2:0] Humidity oversampling
* 000 Skipped
* 001 oversampling x1
* 010 oversampling x2
* 011 oversampling x4
* 100 oversampling x8
* 101,others oversampling x16
*/
#define BME280_CTRL_HUM_VAL (0x01)
/* [7:5] Pressure oversampling
* 000 Skipped
* 001 oversampling x1
* 010 oversampling x2
* 011 oversampling x4
* 100 oversampling x8
* 101,others oversampling x16
* [4:2] Temperature oversampling
* 000 Skipped
* 001 oversampling x1
* 010 oversampling x2
* 011 oversampling x4
* 100 oversampling x8
* 101,others oversampling x16
* [1:0] Mode
* 00 Sleep mode
* 11 Normal mode
*/
#define BME280_CTRL_MEAS_VAL (0x27)
/* [7:5] t_standby[ms]
* 000 0.5
* 001 62.5
* 010 125
* 011 250
* 100 500
* 101 1000
* 110 10
* 111 20
* [4:2] Filter corefficient
* 000 Filter off
* 001 2
* 010 4
* 011 8
* 100,others 16
* [0] SPI interface
* 0 4-wire
* 1 3-wire
*/
#define BME280_CONFIG_VAL (0xA0)
static void readTrim(void);
static void readData(void);
static int32_t calibration_T(int32_t adc_T);
static uint32_t calibration_P(int32_t adc_P);
static uint32_t calibration_H(int32_t adc_H);
static uint32_t hum_raw,temp_raw,pres_raw;
static uint16_t dig_T1;
static int16_t dig_T2, dig_T3;
static uint16_t dig_P1;
static int16_t dig_P2, dig_P3, dig_P4, dig_P5, dig_P6, dig_P7, dig_P8, dig_P9;
static uint8_t dig_H1, dig_H3;
static int16_t dig_H2, dig_H4, dig_H5;
static int8_t dig_H6;
static int32_t t_fine;
/* Private */
static void readTrim(void) {
uint8_t data[32];
i2c_read_register(BME280_ADDRESS, BME280_REG_CALIB00, &data[0], 24, I2C_BME280_TIMEOUT);
i2c_read_register(BME280_ADDRESS, BME280_REG_CALIB25, &data[25], 1, I2C_BME280_TIMEOUT);
i2c_read_register(BME280_ADDRESS, BME280_REG_CALIB26, &data[25], 7, I2C_BME280_TIMEOUT);
dig_T1 = (data[1] << 8) | data[0];
dig_T2 = (data[3] << 8) | data[2];
dig_T3 = (data[5] << 8) | data[4];
dig_P1 = (data[7] << 8) | data[6];
dig_P2 = (data[9] << 8) | data[8];
dig_P3 = (data[11]<< 8) | data[10];
dig_P4 = (data[13]<< 8) | data[12];
dig_P5 = (data[15]<< 8) | data[14];
dig_P6 = (data[17]<< 8) | data[16];
dig_P7 = (data[19]<< 8) | data[18];
dig_P8 = (data[21]<< 8) | data[20];
dig_P9 = (data[23]<< 8) | data[22];
dig_H1 = data[24];
dig_H2 = (data[26]<< 8) | data[25];
dig_H3 = data[27];
dig_H4 = (data[28]<< 4) | (0x0F & data[29]);
dig_H5 = (data[30] << 4) | ((data[29] >> 4) & 0x0F);
dig_H6 = data[31];
return;
}
static void readData(void) {
uint8_t data[8];
i2c_read_register(BME280_ADDRESS, 0xF7, &data[0], 8, I2C_BME280_TIMEOUT);
pres_raw = data[0];
pres_raw = (pres_raw<<8) | data[1];
pres_raw = (pres_raw<<4) | (data[2] >> 4);
temp_raw = data[3];
temp_raw = (temp_raw<<8) | data[4];
temp_raw = (temp_raw<<4) | (data[5] >> 4);
hum_raw = data[6];
hum_raw = (hum_raw << 8) | data[7];
return;
}
static int32_t calibration_T(int32_t adc_T) {
int32_t var1, var2, T;
var1 = ((((adc_T >> 3) - ((int32_t)dig_T1<<1))) * ((int32_t)dig_T2)) >> 11;
var2 = (((((adc_T >> 4) - ((int32_t)dig_T1)) * ((adc_T>>4) - ((int32_t)dig_T1))) >> 12) * ((int32_t)dig_T3)) >> 14;
t_fine = var1 + var2;
T = (t_fine * 5 + 128) >> 8;
return T;
}
static uint32_t calibration_P(int32_t adc_P) {
int32_t var1, var2;
uint32_t P;
var1 = (((int32_t)t_fine)>>1) - (int32_t)64000;
var2 = (((var1>>2) * (var1>>2)) >> 11) * ((int32_t)dig_P6);
var2 = var2 + ((var1*((int32_t)dig_P5))<<1);
var2 = (var2>>2)+(((int32_t)dig_P4)<<16);
var1 = (((dig_P3 * (((var1>>2)*(var1>>2)) >> 13)) >>3) + ((((int32_t)dig_P2) * var1)>>1))>>18;
var1 = ((((32768+var1))*((int32_t)dig_P1))>>15);
if (var1 == 0) {
return 0;
}
P = (((uint32_t)(((int32_t)1048576)-adc_P)-(var2>>12)))*3125;
if( P < 0x80000000 ) {
P = (P << 1) / ((uint32_t) var1);
} else {
P = (P / (uint32_t)var1) * 2;
}
var1 = (((int32_t)dig_P9) * ((int32_t)(((P>>3) * (P>>3))>>13)))>>12;
var2 = (((int32_t)(P>>2)) * ((int32_t)dig_P8))>>13;
P = (uint32_t)((int32_t)P + ((var1 + var2 + dig_P7) >> 4));
return P;
}
static uint32_t calibration_H(int32_t adc_H) {
int32_t v_x1;
v_x1 = (t_fine - ((int32_t)76800));
v_x1 = (((((adc_H << 14) -(((int32_t)dig_H4) << 20) - (((int32_t)dig_H5) * v_x1)) +
((int32_t)16384)) >> 15) * (((((((v_x1 * ((int32_t)dig_H6)) >> 10) *
(((v_x1 * ((int32_t)dig_H3)) >> 11) + ((int32_t) 32768))) >> 10) + (( int32_t)2097152)) *
((int32_t) dig_H2) + 8192) >> 14));
v_x1 = (v_x1 - (((((v_x1 >> 15) * (v_x1 >> 15)) >> 7) * ((int32_t)dig_H1)) >> 4));
v_x1 = (v_x1 < 0 ? 0 : v_x1);
v_x1 = (v_x1 > 419430400 ? 419430400 : v_x1);
return (uint32_t)(v_x1 >> 12);
}
/* Public */
void bme280_init(void) {
uint8_t ctrl_hum_reg;
uint8_t ctrl_meas_reg;
uint8_t config_reg;
ctrl_hum_reg = BME280_CTRL_HUM_VAL;
ctrl_meas_reg = BME280_CTRL_MEAS_VAL;
config_reg = BME280_CONFIG_VAL;
i2c_init();
i2c_write_register(BME280_ADDRESS, BME280_REG_CTRL_HUM, &ctrl_hum_reg, 1, I2C_BME280_TIMEOUT);
i2c_write_register(BME280_ADDRESS, BME280_REG_CTRL_MEAS, &ctrl_meas_reg, 1, I2C_BME280_TIMEOUT);
i2c_write_register(BME280_ADDRESS, BME280_REG_CONFIG, &config_reg, 1, I2C_BME280_TIMEOUT);
readTrim();
return;
}
void bme280_exec(void) {
readData();
return;
}
double bme280_getTemp(void) {
double temp_act;
int32_t temp_cal;
temp_cal = calibration_T(temp_raw);
temp_act = (double)temp_cal / 100.0;
return temp_act;
}
double bme280_getPress(void) {
double press_act;
uint32_t press_cal;
press_cal = calibration_P(pres_raw);
press_act = (double)press_cal / 100.0;
return press_act;
}
double bme280_getHum(void) {
double hum_act;
uint32_t hum_cal;
hum_cal = calibration_H(hum_raw);
hum_act = (double)hum_cal / 1024.0;
return hum_act;
}
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