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bmp180.c
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bmp180.c
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#include <driver/i2c.h>
#include <esp_log.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include "sdkconfig.h"
#define BMP180_ADDRESS 0x77
enum
{
BMP085_REGISTER_CAL_AC1 = 0xAA, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_AC2 = 0xAC, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_AC3 = 0xAE, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_AC4 = 0xB0, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_AC5 = 0xB2, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_AC6 = 0xB4, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_B1 = 0xB6, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_B2 = 0xB8, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_MB = 0xBA, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_MC = 0xBC, // R Calibration data (16 bits)
BMP085_REGISTER_CAL_MD = 0xBE, // R Calibration data (16 bits)
BMP085_REGISTER_CHIPID = 0xD0,
BMP085_REGISTER_VERSION = 0xD1,
BMP085_REGISTER_SOFTRESET = 0xE0,
BMP085_REGISTER_CONTROL = 0xF4,
BMP085_REGISTER_TEMPDATA = 0xF6,
BMP085_REGISTER_PRESSUREDATA = 0xF6,
BMP085_REGISTER_READTEMPCMD = 0x2E,
BMP085_REGISTER_READPRESSURECMD = 0x34 // 0011 0100
};
typedef enum
{
BMP085_MODE_ULTRALOWPOWER = 0,
BMP085_MODE_STANDARD = 1,
BMP085_MODE_HIGHRES = 2,
BMP085_MODE_ULTRAHIGHRES = 3
} bmp085_mode_t;
//static char tag[] = "bmp180";
static short readRegister16(uint8_t reg) {
i2c_cmd_handle_t cmd = i2c_cmd_link_create();
i2c_master_start(cmd);
i2c_master_write_byte(cmd, (BMP180_ADDRESS << 1) | I2C_MASTER_WRITE, 1 /* expect ack */);
i2c_master_write_byte(cmd, reg, 1);
i2c_master_stop(cmd);
i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000/portTICK_PERIOD_MS);
i2c_cmd_link_delete(cmd);
uint8_t msb;
uint8_t lsb;
cmd = i2c_cmd_link_create();
i2c_master_start(cmd);
i2c_master_write_byte(cmd, (BMP180_ADDRESS << 1) | I2C_MASTER_READ, 1 /* expect ack */);
i2c_master_read_byte(cmd, &msb, 1);
i2c_master_read_byte(cmd, &lsb, 0);
i2c_master_stop(cmd);
i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000/portTICK_PERIOD_MS);
i2c_cmd_link_delete(cmd);
short ret = (short)((msb << 8) | lsb);
return ret;
}
static int readRegister24(uint8_t reg) {
i2c_cmd_handle_t cmd = i2c_cmd_link_create();
i2c_master_start(cmd);
i2c_master_write_byte(cmd, (BMP180_ADDRESS << 1) | I2C_MASTER_WRITE, 1 /* expect ack */);
i2c_master_write_byte(cmd, reg, 1);
i2c_master_stop(cmd);
i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000/portTICK_PERIOD_MS);
i2c_cmd_link_delete(cmd);
uint8_t msb;
uint8_t lsb;
uint8_t xlsb;
cmd = i2c_cmd_link_create();
i2c_master_start(cmd);
i2c_master_write_byte(cmd, (BMP180_ADDRESS << 1) | I2C_MASTER_READ, 1 /* expect ack */);
i2c_master_read_byte(cmd, &msb, 1);
i2c_master_read_byte(cmd, &lsb, 1);
i2c_master_read_byte(cmd, &xlsb, 0);
i2c_master_stop(cmd);
i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000/portTICK_PERIOD_MS);
i2c_cmd_link_delete(cmd);
int ret = (int)((msb << 16) | (lsb << 8) | xlsb);
return ret;
}
static uint32_t readUncompensatedTemp() {
i2c_cmd_handle_t cmd = i2c_cmd_link_create();
i2c_master_start(cmd);
i2c_master_write_byte(cmd, (BMP180_ADDRESS << 1) | I2C_MASTER_WRITE, 1 /* expect ack */);
i2c_master_write_byte(cmd, BMP085_REGISTER_CONTROL, 1);
i2c_master_write_byte(cmd, BMP085_REGISTER_READTEMPCMD, 1);
i2c_master_stop(cmd);
i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000/portTICK_PERIOD_MS);
i2c_cmd_link_delete(cmd);
vTaskDelay(5/portTICK_PERIOD_MS);
long ret = (unsigned short)readRegister16(BMP085_REGISTER_TEMPDATA);
return ret;
}
static uint32_t readUncompensatedPressure(uint32_t mode) {
i2c_cmd_handle_t cmd = i2c_cmd_link_create();
i2c_master_start(cmd);
i2c_master_write_byte(cmd, (BMP180_ADDRESS << 1) | I2C_MASTER_WRITE, 1 /* expect ack */);
i2c_master_write_byte(cmd, BMP085_REGISTER_CONTROL, 1);
i2c_master_write_byte(cmd, BMP085_REGISTER_READPRESSURECMD + (mode << 6), 1);
i2c_master_stop(cmd);
i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000/portTICK_PERIOD_MS);
i2c_cmd_link_delete(cmd);
switch(mode) {
case BMP085_MODE_ULTRALOWPOWER:
vTaskDelay(5/portTICK_PERIOD_MS);
break;
case BMP085_MODE_STANDARD:
vTaskDelay(8/portTICK_PERIOD_MS);
break;
case BMP085_MODE_HIGHRES:
vTaskDelay(14/portTICK_PERIOD_MS);
break;
case BMP085_MODE_ULTRAHIGHRES:
default:
vTaskDelay(26/portTICK_PERIOD_MS);
break;
}
long ret;
if (mode != BMP085_MODE_ULTRAHIGHRES) {
ret = readRegister24(BMP085_REGISTER_PRESSUREDATA);
} else {
ret = readRegister24(BMP085_REGISTER_PRESSUREDATA);
}
return ret >> (8-mode);
}
double centigrade_to_fahrenheit(double centigrade) {
return centigrade * 9 / 5 + 32.0;
}
double pascals_to_inHg(double pressure) {
return pressure * 0.00029530;
}
void echantillon(float * temperature, uint32_t * press) {
short AC1 = readRegister16(BMP085_REGISTER_CAL_AC1);
short AC2 = readRegister16(BMP085_REGISTER_CAL_AC2);
short AC3 = readRegister16(BMP085_REGISTER_CAL_AC3);
unsigned short AC4 = readRegister16(BMP085_REGISTER_CAL_AC4);
unsigned short AC5 = readRegister16(BMP085_REGISTER_CAL_AC5);
unsigned short AC6 = readRegister16(BMP085_REGISTER_CAL_AC6);
short B1 = readRegister16(BMP085_REGISTER_CAL_B1);
short B2 = readRegister16(BMP085_REGISTER_CAL_B2);
short MB = readRegister16(BMP085_REGISTER_CAL_MB);
short MC = readRegister16(BMP085_REGISTER_CAL_MC);
short MD = readRegister16(BMP085_REGISTER_CAL_MD);
// printf("Params: AC1: %d, AC2: %d, AC3: %d, AC4:%d, AC5: %d, AC6: %d, B1: %d, B2: %d, MB: %d, MC: %d, MD: %d\n",
// AC1, AC2, AC3, AC4, AC5, AC6, B1, B2, MB, MC, MD);
int32_t bmpMode = BMP085_MODE_STANDARD;
int32_t UT = readUncompensatedTemp();
int32_t UP = readUncompensatedPressure(bmpMode);
int32_t X1 = (UT - (int32_t)AC6) * ((int32_t)AC5) >> 15;
int32_t X2 = ((int32_t)MC<<11) / (X1+(int32_t)MD);
int32_t B5 = X1 + X2;
float temp = ((B5 + 8)>>4)/10.0;
*temperature=temp;
// printf("Temp = %.1foC = %.1foF\n", temp, centigrade_to_fahrenheit(temp));
int32_t B6 = B5 - 4000;
X1 = (B2 * (B6 * B6) >> 12) >> 11;
X2 = (AC2 * B6) >> 11;
int32_t X3 = X1 + X2;
int32_t B3 = (((((int32_t)AC1)*4 + X3) << bmpMode) + 2) >> 2;
X1 = (AC3 * B6) >> 13;
X2 = (B1 * ((B6 * B6) >> 12)) >> 16;
X3 = ((X1 + X2) + 2) >> 2;
uint32_t B4 = ((uint32_t)AC4 * (uint32_t)(X3 + 32768)) >> 15;
uint32_t B7 = ((((uint32_t)UP) - B3) * (50000 >> bmpMode));
int32_t P;
if (B7 < 0x80000000) {
P = (B7 << 1) / B4;
} else {
P = (B7 / B4) << 1;
}
X1 = (P >> 8) * (P >> 8);
X1 = (X1 * 3038) >> 16;
X2 = (-7357 * P) >> 16;
int32_t pressure = P + ((X1 + X2 + 3791) >> 4);
*press=pressure;
// printf("pressure = %d pa, = %f inHg, UP=%d\n", pressure, pascals_to_inHg(pressure), UP);
}