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R.P.Clark 2023-09-17 21:31:02 +01:00
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2
Makefile Normal file
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all:
gcc -O2 -std=c99 -Wall -Wextra main.c bme680.c i2c.c -o bme680

2
README.md Normal file
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# bme680
test

217
bme680.c Normal file
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#include "bme680.h"
const double const_array1[16] = {
1,
1,
1,
1,
1,
0.99,
1,
0.992,
1,
1,
0.998,
0.995,
1,
0.99,
1,
1
};
const double const_array2[16] = {
8000000,
4000000,
2000000,
1000000,
499500.4995,
248262.1648,
125000,
63004.03226,
31281.28128,
15625,
7812.5,
3906.25,
1953.125,
976.5625,
488.28125,
244.140625
};
const int const_array1_int[16] = {
2147483647,
2147483647,
2147483647,
2147483647,
2147483647,
2126008810,
2147483647,
2130303777,
2147483647,
2147483647,
2143188679,
2136746228,
2147483647,
2126008810,
2147483647,
2147483647
};
const int const_array2_int[16] = {
4096000000, // too big ?
2048000000,
1024000000,
512000000,
255744255,
127110228,
64000000,
32258064,
16016016,
8000000,
4000000,
2000000,
1000000,
500000,
250000,
125000
};
static double calc_temp_comp_1 ( uint32_t temp_adc , bme680_t *bme680) {
double var1, var2, temp_comp;
bme680_calibration *cal;
cal = &bme680->cal;
var1 = (((double)temp_adc / 16384.0) - ((double)cal->par_t1 / 1024.0)) *
(double)cal->par_t2;
var2 = ((((double)temp_adc / 131072.0) - ((double)cal->par_t1 / 8192.0)) *
(((double)temp_adc / 131072.0) - ((double)cal->par_t1 / 8192.0))) *
((double)cal->par_t3 * 16.0);
bme680->tfine_double = var1 + var2;
temp_comp = (var1 + var2) / 5120.0;
bme680->temp_comp_double = temp_comp;
return temp_comp;
}
static int calc_temp_comp_2 (uint32_t temp_adc, bme680_t *bme680) {
int32_t var1, var2, var3, temp_comp;
bme680_calibration *cal;
cal = &bme680->cal;
var1 = ((int32_t)temp_adc >> 3) - ((int32_t) cal->par_t1 << 1);
var2 = (var1 * (int32_t)cal->par_t2) >> 11;
var3 = ((((var1 >> 1) * (var1 >> 1)) >> 12) * ((int32_t)cal->par_t3 << 4)) >> 14;
bme680->tfine_int = var2 + var3;
temp_comp = (( (var2 + var3) * 5) + 128) >> 8;
bme680->temp_comp_int = temp_comp;
return temp_comp;
}
static double calc_press_comp_1 ( uint32_t press_adc , bme680_t *bme680 ) {
double var1, var2, var3, press_comp;
bme680_calibration *cal;
cal = &bme680->cal;
var1 = (bme680->tfine_double / 2.0) - 64000.0;
var2 = var1 * var1 * ((double)cal->par_p6 / 131072.0);
var2 = var2 + (var1 * (double)cal->par_p5 * 2.0);
var2 = (var2 / 4.0) + ((double)cal->par_p4 * 65536.0);
var1 = ((((double)cal->par_p3 * var1 * var1) / 16384.0) +
((double)cal->par_p2 * var1)) / 524288.0;
var1 = (1.0 + (var1 / 32768.0)) * (double)cal->par_p1;
press_comp = 1048576.0 - (double)press_adc;
press_comp = ((press_comp - (var2 / 4096.0)) * 6250.0) / var1;
var1 = ((double)cal->par_p9 * press_comp * press_comp) / 2147483648.0;
var2 = press_comp * ((double)cal->par_p8 / 32768.0);
var3 = (press_comp / 256.0) * (press_comp / 256.0) * (press_comp / 256.0) * (cal->par_p10 / 131072.0);
press_comp = press_comp + (var1 + var2 + var3 + ((double)cal->par_p7 * 128.0)) / 16.0;
bme680->press_comp_double = press_comp;
return press_comp;
}
static int calc_press_comp_2 ( uint32_t press_adc , bme680_t *bme680 ) {
uint32_t var1, var2, var3, press_comp;
bme680_calibration *cal;
cal = &bme680->cal;
var1 = ((int32_t)bme680->tfine_int >> 1) - 64000;
var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) * (int32_t)cal->par_p6) >> 2;
var2 = var2 + ((var1 * (int32_t)cal->par_p5) << 1);
var2 = (var2 >> 2) + ((int32_t)cal->par_p4 << 16);
var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
((int32_t)cal->par_p3 << 5)) >> 3) + (((int32_t)cal->par_p2 * var1) >> 1);
var1 = var1 >> 18;
var1 = ((32768 + var1) * (int32_t)cal->par_p1) >> 15;
press_comp = 1048576 - press_adc; // says "press_raw" in the bosch example
press_comp = (uint32_t)((press_comp - (var2 >> 12)) * ((uint32_t)3125));
if (press_comp >= (1 << 30))
press_comp = ((press_comp / (uint32_t)var1) << 1);
else
press_comp = ((press_comp << 1) / (uint32_t)var1);
var1 = ((int32_t)cal->par_p9 * (int32_t)(((press_comp >> 3) *
(press_comp >> 3)) >> 13)) >> 12;
var2 = ((int32_t)(press_comp >> 2) * (int32_t)cal->par_p8) >> 13;
var3 = ((int32_t)(press_comp >> 8) * (int32_t)(press_comp >> 8) *
(int32_t)(press_comp >> 8) * (int32_t)cal->par_p10) >> 17;
press_comp = (int32_t)(press_comp) + ((var1 + var2 + var3 + ((int32_t)cal->par_p7 << 7)) >> 4);
bme680->press_comp_int = press_comp;
return press_comp;
}
static double calc_hum_comp_1 ( uint32_t hum_adc , bme680_t *bme680 ) {
double var1, var2, var3, var4, hum_comp;
bme680_calibration *cal;
cal = &bme680->cal;
var1 = hum_adc - (((double)cal->par_h1 * 16.0) + (((double)cal->par_h3 / 2.0) * bme680->temp_comp_double));
var2 = var1 * (((double)cal->par_h2 / 262144.0) * (1.0 + (((double)cal->par_h4 / 16384.0) *
bme680->temp_comp_double) + (((double)cal->par_h5 / 1048576.0) *
bme680->temp_comp_double * bme680->temp_comp_double)));
var3 = (double)cal->par_h6 / 16384.0;
var4 = (double)cal->par_h7 / 2097152.0;
hum_comp = var2 + ((var3 + (var4 * bme680->temp_comp_double)) * var2 * var2);
bme680->hum_comp_double = hum_comp;
return hum_comp;
}
static int calc_hum_comp_2 ( uint32_t hum_adc , bme680_t *bme680 ) {
uint32_t var1, var2, var3, var4, var5, var6, temp_scaled, hum_comp;
bme680_calibration *cal;
cal = &bme680->cal;
temp_scaled = (int32_t)(bme680->temp_comp_int);
var1 = (int32_t)hum_adc - (int32_t)((int32_t)cal->par_h1 << 4) -
(((temp_scaled * (int32_t)cal->par_h3) / ((int32_t)100)) >> 1);
var2 = ((int32_t)cal->par_h2 * (((temp_scaled *
(int32_t)cal->par_h4) / ((int32_t)100)) +
(((temp_scaled * ((temp_scaled * (int32_t)cal->par_h5) /
((int32_t)100))) >> 6) / ((int32_t)100)) + ((int32_t)(1 << 14)))) >> 10;
var3 = var1 * var2;
var4 = (((int32_t)cal->par_h6 << 7) +
((temp_scaled * (int32_t)cal->par_h7) / ((int32_t)100))) >> 4;
var5 = ((var3 >> 14) * (var3 >> 14)) >> 10;
var6 = (var4 * var5) >> 1;
hum_comp = (((var3 + var6) >> 10) * ((int32_t)1000)) >> 12;
bme680->hum_comp_int = hum_comp;
return hum_comp;
}

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bme680.h Normal file
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#pragma once
#include <stdint.h>
typedef struct {
uint16_t par_t1;
uint16_t par_t2;
uint16_t par_t3; // 8 bit word
uint16_t par_p1;
uint16_t par_p2;
uint16_t par_p3; // 8 bit word
uint16_t par_p4;
uint16_t par_p5;
uint16_t par_p6; // 8 bit word
uint16_t par_p7; // 8 bit word
uint16_t par_p8;
uint16_t par_p9;
uint16_t par_p10; //8 bit word
uint16_t par_h1;
uint16_t par_h2;
uint16_t par_h3;
uint16_t par_h4;
uint16_t par_h5;
uint16_t par_h6;
uint16_t par_h7;
uint16_t par_g1;
uint16_t par_g2;
uint16_t par_g3;
uint16_t range_switching_error;
} bme680_calibration;
typedef struct {
int tfine_int;
double tfine_double;
double temp_comp_double;
int temp_comp_int;
double press_comp_double;
int press_comp_int;
double hum_comp_double;
int hum_comp_int;
bme680_calibration cal;
} bme680_t;

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i2c.c Normal file
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#include <stdio.h>
#include <fcntl.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <stdint.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <stdlib.h>
#define MY_DEVICE "/dev/i2c-1"
#define MY_DEVICE_ADDRESS 0x77
int i2c_init(const char *dev, uint8_t addr) {
int fd = -1;
fd = open(dev, O_RDWR);
if (fd < 0) {
fprintf(stderr, "could not open device: %s\n", dev);
return -1;
}
if (ioctl(fd, I2C_SLAVE, addr) < 0) {
fprintf(stderr, "failed to acquire bus/talk to slave\n");
close(fd);
return -1;
}
return fd;
}
int i2c_read_reg(int fd, uint8_t reg, uint8_t length, uint8_t *buf) {
uint8_t cmd[2] = {reg, 0x00};
write(fd, cmd, 2);
if (read(fd, buf, length) != length) {
fprintf(stderr, "error read()\n");
return 1;
}
return 0;
}
uint8_t i2c_read_reg2(int fd, uint8_t reg) {
uint8_t buf;
i2c_read_reg(fd, reg, 1, &buf);
return buf;
}
int i2c_write_reg(int fd, uint8_t reg, uint8_t value) {
uint8_t cmd[2] = {reg, value};
if (write(fd, cmd, 2) != 2) {
fprintf(stderr, "error write()\n");
return 1;
}
return 0;
}
int main2(void) {
int res;
uint8_t cmd_buf[2] = {0x00, 0x00};
int fd = i2c_init(MY_DEVICE, MY_DEVICE_ADDRESS);
if (i2c_read_reg(fd, 0xD0, 1, (uint8_t *)&res) != 0) {
fprintf(stderr, "ddd\n");
}
printf("%X\n", res);
printf("%X\n", i2c_read_reg2(fd, 0xD0));
close(fd);
return 0;
}

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i2c.h Normal file
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#pragma once
#include <stdint.h>
int i2c_init(const char *, uint8_t);
int i2c_read_reg(int, uint8_t, uint8_t, uint8_t *);
uint8_t i2c_read_reg2(uint8_t, uint8_t);
int i2c_write_reg(int, uint8_t, uint8_t);

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main.c Normal file
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#include <stdio.h>
#include "bme680.h"
#include "i2c.h"
#define DEVICE "/dev/i2c-1"
#define ADDRESS 0x77
int main(){
int fd = i2c_init(DEVICE, ADDRESS);
printf("%X\n", i2c_read_reg2(fd, 0xD0));
close(fd);
return 0;
}