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rewrite wip

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This commit is contained in:
William Clark 2023-11-04 03:42:14 +00:00
parent a17c276f35
commit 7608e16e86
6 changed files with 389 additions and 315 deletions
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1
Makefile
View File

@ -1,5 +1,6 @@
CC=gcc
OPT=-O2 -std=c99 -Wall -Wextra
# OPT=-O0 -g3 -std=c99 -Wall -Wextra -pedantic
CFLAGS=-I. $(OPT)
CFILES=$(wildcard ./*.c)
OBJECTS=$(patsubst %.c,%.o, $(CFILES))

356
bme680.c
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@ -1,309 +1,248 @@
#include "bme680.h"
#include "i2c.h"
#include <stdio.h>
#include "registers.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
int bme680_init(bme680_t *bme680) {
uint8_t car;
if (bme680->dev.init() != 0) {
return 1;
}
if (bme680->dev.read(REG_ID, &car, 1) != 0) {
return 1;
}
if (car != 0x61) {
return 1;
}
return 0;
}
static 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
static 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,
static 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 int const_array2_int[16] = {
4096000000, 2048000000, 1024000000, 512000000, 255744255,
127110228, 64000000, 32258064, 16016016, 8000000, 4000000,
2000000, 1000000, 500000, 250000, 125000
};
double calc_temp_comp_1 ( uint32_t temp_adc , bme680_t *bme680) {
static void calc_temp_comp_1 (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;
var1 = (((double)bme680->adc.temp / 16384.0) - ((double)bme680->cal.par_t1 / 1024.0)) *
(double)bme680->cal.par_t2;
var2 = ((((double)bme680->adc.temp / 131072.0) - ((double)bme680->cal.par_t1 / 8192.0)) *
(((double)bme680->adc.temp / 131072.0) - ((double)bme680->cal.par_t1 / 8192.0))) *
((double)bme680->cal.par_t3 * 16.0);
bme680->fcomp.tfine = var1 + var2;
temp_comp = (var1 + var2) / 5120.0;
bme680->temp_comp_double = temp_comp;
return temp_comp;
bme680->fcomp.temp = temp_comp;
}
int calc_temp_comp_2 (uint32_t temp_adc, bme680_t *bme680) {
static void calc_temp_comp_2 (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;
var1 = ((int32_t)bme680->adc.temp >> 3) - ((int32_t) bme680->cal.par_t1 << 1);
var2 = (var1 * (int32_t)bme680->cal.par_t2) >> 11;
var3 = ((((var1 >> 1) * (var1 >> 1)) >> 12) * ((int32_t)bme680->cal.par_t3 << 4)) >> 14;
bme680->icomp.tfine = var2 + var3;
temp_comp = (((var2 + var3) * 5) + 128) >> 8;
bme680->icomp.temp = temp_comp;
}
double calc_press_comp_1 ( uint32_t press_adc , bme680_t *bme680 ) {
static void calc_press_comp_1 (bme680_t *bme680) {
double var1, var2, var3, press_comp;
bme680_calibration *cal;
cal = &bme680->cal;
var1 = ((double)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;
var1 = ((double)bme680->fcomp.tfine / 2.0) - 64000.0;
var2 = var1 * var1 * ((double)bme680->cal.par_p6 / 131072.0);
var2 = var2 + (var1 * (double)bme680->cal.par_p5 * 2.0);
var2 = (var2 / 4.0) + ((double)bme680->cal.par_p4 * 65536.0);
var1 = ((((double)bme680->cal.par_p3 * var1 * var1) / 16384.0) +
((double)bme680->cal.par_p2 * var1)) / 524288.0;
var1 = (1.0 + (var1 / 32768.0)) * (double)bme680->cal.par_p1;
press_comp = 1048576.0 - (double)bme680->adc.press;
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);
var1 = ((double)bme680->cal.par_p9 * press_comp * press_comp) / 2147483648.0;
var2 = press_comp * ((double)bme680->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;
(press_comp / 256.0) * (bme680->cal.par_p10 / 131072.0);
press_comp = press_comp + (var1 + var2 + var3 + ((double)bme680->cal.par_p7 * 128.0)) / 16.0;
bme680->fcomp.press = press_comp;
}
int calc_press_comp_2 ( uint32_t press_adc , bme680_t *bme680 ) {
static void calc_press_comp_2 (bme680_t *bme680 ) {
int32_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 = ((int32_t)bme680->icomp.tfine >> 1) - 64000;
var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) * (int32_t)bme680->cal.par_p6) >> 2;
var2 = var2 + ((var1 * (int32_t)bme680->cal.par_p5) << 1);
var2 = (var2 >> 2) + ((int32_t)bme680->cal.par_p4 << 16);
var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
((int32_t)cal->par_p3 << 5)) >> 3) + (((int32_t)cal->par_p2 * var1) >> 1);
((int32_t)bme680->cal.par_p3 << 5)) >> 3) + (((int32_t)bme680->cal.par_p2 * var1) >> 1);
var1 = var1 >> 18;
var1 = ((32768 + var1) * (int32_t)cal->par_p1) >> 15;
press_comp = 1048576 - press_adc; // bosch code pg 19 says "press_raw" here ???
var1 = ((32768 + var1) * (int32_t)bme680->cal.par_p1) >> 15;
press_comp = 1048576 - bme680->adc.press; // bosch code pg 19 says "press_raw" here ???
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) *
var1 = ((int32_t)bme680->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;
var2 = ((int32_t)(press_comp >> 2) * (int32_t)bme680->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;
(int32_t)(press_comp >> 8) * (int32_t)bme680->cal.par_p10) >> 17;
press_comp = (int32_t)(press_comp) + ((var1 + var2 + var3 + ((int32_t)bme680->cal.par_p7 << 7)) >> 4);
bme680->icomp.press = press_comp;
}
double calc_hum_comp_1 ( uint32_t hum_adc , bme680_t *bme680 ) {
static void calc_hum_comp_1 (bme680_t *bme680) {
double var1, var2, var3, var4, hum_comp, temp_comp;
bme680_calibration *cal;
cal = &bme680->cal;
temp_comp = bme680->temp_comp_double;
temp_comp = bme680->fcomp.temp;
var1 = hum_adc - (((double)cal->par_h1 * 16.0) + (((double)cal->par_h3 / 2.0) * temp_comp));
var2 = var1 * (((double)cal->par_h2 / 262144.0) * (1.0 + (((double)cal->par_h4 / 16384.0) *
temp_comp) + (((double)cal->par_h5 / 1048576.0) * temp_comp * temp_comp)));
var3 = (double)cal->par_h6 / 16384.0;
var4 = (double)cal->par_h7 / 2097152.0;
var1 = bme680->adc.hum - (((double)bme680->cal.par_h1 * 16.0) + (((double)bme680->cal.par_h3 / 2.0) * temp_comp));
var2 = var1 * (((double)bme680->cal.par_h2 / 262144.0) * (1.0 + (((double)bme680->cal.par_h4 / 16384.0) *
temp_comp) + (((double)bme680->cal.par_h5 / 1048576.0) * temp_comp * temp_comp)));
var3 = (double)bme680->cal.par_h6 / 16384.0;
var4 = (double)bme680->cal.par_h7 / 2097152.0;
hum_comp = var2 + ((var3 + (var4 * temp_comp)) * var2 * var2);
bme680->hum_comp_double = hum_comp;
return hum_comp;
bme680->fcomp.hum = hum_comp;
}
int calc_hum_comp_2 ( uint32_t hum_adc , bme680_t *bme680 ) {
static void calc_hum_comp_2 (bme680_t *bme680) {
int32_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) /
temp_scaled = (int32_t)bme680->icomp.temp;
var1 = (int32_t)bme680->adc.hum - (int32_t)((int32_t)bme680->cal.par_h1 << 4) -
(((temp_scaled * (int32_t)bme680->cal.par_h3) / ((int32_t)100)) >> 1);
var2 = ((int32_t)bme680->cal.par_h2 * (((temp_scaled * (int32_t)bme680->cal.par_h4) / ((int32_t)100)) +
(((temp_scaled * ((temp_scaled * (int32_t)bme680->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;
var4 = (((int32_t)bme680->cal.par_h6 << 7) +
((temp_scaled * (int32_t)bme680->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;
bme680->icomp.hum = hum_comp;
}
int bme680_calibrate ( int fd , bme680_calibration *cal ) {
int bme680_calibrate(bme680_t *bme680) {
uint8_t buffer[3] = {0, 0 ,0};
int err = 0;
// start with temp params
err |= i2c_read_reg(fd, 0xE9, 2, buffer);
cal->par_t1 = (buffer[1] << 8) | buffer[0];
err |= bme680->dev.read(0xE9, buffer, 2);
bme680->cal.par_t1 = (buffer[1] << 8) | buffer[0];
err |= i2c_read_reg(fd, 0x8A, 2, buffer);
cal->par_t2 = (buffer[1] << 8) | buffer[0];
err |= bme680->dev.read(0x8A, buffer, 2);
bme680->cal.par_t2 = (buffer[1] << 8) | buffer[0];
err |= i2c_read_reg(fd, 0x8C, 1, buffer);
cal->par_t3 = buffer[0];
err |= bme680->dev.read(0x8C, buffer, 1);
bme680->cal.par_t3 = buffer[0];
// pressure
err |= i2c_read_reg(fd, 0x8E, 2, buffer);
cal->par_p1 = (buffer[1] << 8) | buffer[0];
err |= bme680->dev.read(0x8E, buffer, 2);
bme680->cal.par_p1 = (buffer[1] << 8) | buffer[0];
err |= i2c_read_reg(fd, 0x90, 2 , buffer);
cal->par_p2 = (buffer[1] << 8) | buffer[0];
err |= bme680->dev.read(0x90, buffer, 2);
bme680->cal.par_p2 = (buffer[1] << 8) | buffer[0];
err |= i2c_read_reg(fd, 0x92, 1, buffer);
cal->par_p3 = buffer[0];
err |= bme680->dev.read(0x92, buffer, 1);
bme680->cal.par_p3 = buffer[0];
err |= i2c_read_reg(fd, 0x94, 2, buffer);
cal->par_p4 = (buffer[1] << 8) | buffer[0];
err |= bme680->dev.read(0x94, buffer, 2);
bme680->cal.par_p4 = (buffer[1] << 8) | buffer[0];
err |= i2c_read_reg(fd, 0x96, 2, buffer);
cal->par_p5 = (buffer[1] << 8) | buffer[0];
err |= bme680->dev.read(0x96, buffer, 2);
bme680->cal.par_p5 = (buffer[1] << 8) | buffer[0];
err |= i2c_read_reg(fd, 0x99, 1, buffer);
cal->par_p6 = buffer[0];
err |= bme680->dev.read(0x99, buffer, 1);
bme680->cal.par_p6 = buffer[0];
err |= i2c_read_reg(fd, 0x98, 1, buffer); // strange order
cal->par_p7 = buffer[0];
err |= bme680->dev.read(0x98, buffer, 1); // strange order
bme680->cal.par_p7 = buffer[0];
err |= i2c_read_reg(fd, 0x9C, 2, buffer);
cal->par_p8 = (buffer[1] << 8) | buffer[0];
err |= bme680->dev.read(0x9C, buffer, 1);
bme680->cal.par_p8 = (buffer[1] << 8) | buffer[0];
err |= i2c_read_reg(fd, 0x9E, 2, buffer);
cal->par_p9 = (buffer[1] << 8) | buffer[0];
err |= bme680->dev.read(0x9E, buffer, 2);
bme680->cal.par_p9 = (buffer[1] << 8) | buffer[0];
err |= i2c_read_reg(fd, 0xA0, 1, buffer);
cal->par_p10 = buffer[0];
err |= bme680->dev.read(0xA0, buffer, 1);
bme680->cal.par_p10 = buffer[0];
// humidity
err |= i2c_read_reg(fd, 0xE2, 2, buffer);
cal->par_h1 = (buffer[1] << 4) | (buffer[0] & 0xF);
err |= bme680->dev.read(0xE2, buffer, 2);
bme680->cal.par_h1 = (buffer[1] << 4) | (buffer[0] & 0xF);
err |= i2c_read_reg(fd, 0xE1, 2, buffer);
cal->par_h2 = (buffer[0] << 4) | ((buffer[1] >> 4) & 0xF);
err |= bme680->dev.read(0xE1, buffer, 2);
bme680->cal.par_h2 = (buffer[0] << 4) | ((buffer[1] >> 4) & 0xF);
err |= i2c_read_reg(fd, 0xE4, 1, buffer);
cal->par_h3 = buffer[0];
err |= bme680->dev.read(0xE4, buffer, 1);
bme680->cal.par_h3 = buffer[0];
err |= i2c_read_reg(fd, 0xE5, 1, buffer);
cal->par_h4 = buffer[0];
err |= bme680->dev.read(0xE5, buffer, 1);
bme680->cal.par_h4 = buffer[0];
err |= i2c_read_reg(fd, 0xE6, 1, buffer);
cal->par_h5 = buffer[0];
err |= bme680->dev.read(0xE6, buffer, 1);
bme680->cal.par_h5 = buffer[0];
err |= i2c_read_reg(fd, 0xE7, 1, buffer);
cal->par_h6 = buffer[0];
err |= bme680->dev.read(0xE7, buffer, 1);
bme680->cal.par_h6 = buffer[0];
err |= i2c_read_reg(fd, 0xE8, 1, buffer);
cal->par_h7 = buffer[0];
err |= bme680->dev.read(0xE8, buffer, 1);
bme680->cal.par_h7 = buffer[0];
// gas
err |= i2c_read_reg(fd, 0xED, 1, buffer);
cal->par_g1 = buffer[0];
err |= bme680->dev.read(0xED, buffer, 1);
bme680->cal.par_g1 = buffer[0];
err |= i2c_read_reg(fd, 0xEB, 2, buffer);
cal->par_g2 = (buffer[1] << 8) | buffer[0];
err |= bme680->dev.read(0xEB, buffer, 2);
bme680->cal.par_g2 = (buffer[1] << 8) | buffer[0];
err |= i2c_read_reg(fd, 0xEE, 1, buffer);
cal->par_g2 = buffer[0];
err |= bme680->dev.read(0xEE, buffer, 1);
bme680->cal.par_g2 = buffer[0];
// todo more
@ -312,6 +251,7 @@ int bme680_calibrate ( int fd , bme680_calibration *cal ) {
return err;
}
/*
void print_calibration ( bme680_calibration *cal ) {
printf("par_t1: %d\n", cal->par_t1);
printf("par_t2: %d\n", cal->par_t2);
@ -333,4 +273,6 @@ void print_calibration ( bme680_calibration *cal ) {
printf("par_h5: %d\n", cal->par_h5);
printf("par_h6: %d\n", cal->par_h6);
printf("par_h7: %d\n", cal->par_h7);
}
} */

140
bme680.h
View File

@ -1,64 +1,128 @@
#pragma once
#ifndef BME680_H
#define BME680
#include <stdint.h>
typedef struct {
/* connection modes */
#define BME680_SPI 1
#define BME680_I2C 0
/* calculation modes; int or float calc */
#define BME680_MODE_INT 2
#define BME680_MODE_FLOAT 0
#define BME680_MAX_XFER_SIZE 128
/* config values */
#define BME680_OVERSAMPLE_1X 0b001
#define BME680_OVERSAMPLE_2X 0b010
#define BME680_OVERSAMPLE_4X 0b011
#define BME680_OVERSAMPLE_8X 0b100
#define BME680_OVERSAMPLE_16X 0b101
/* IIR filter */
#define BME680_IIR_COEFF_0 0b000
#define BME680_IIR_COEFF_1 0b001
#define BME680_IIR_COEFF_3 0b010
#define BME680_IIR_COEFF_7 0b011
#define BME680_IIR_COEFF_15 0b100
#define BME680_IIR_COEFF_31 0b101
#define BME680_IIR_COEFF_63 0b110
#define BME680_IIR_COEFF_127 0b111
/* user supplied spi/i2c functions */
struct bme680_dev {
int (*init) (void);
int (*read) (uint8_t reg, uint8_t *dst, uint32_t size);
int (*write) (uint8_t reg, uint8_t *src, uint32_t size);
int (*xfer) (uint8_t reg, uint8_t *src, uint8_t *dst, uint32_t size);
int (*deinit) (void);
};
struct bme680_cal {
/* temp calibration */
uint16_t par_t1;
int16_t par_t2;
int8_t par_t3;
int16_t par_t2;
int8_t par_t3;
/* press calibration */
uint16_t par_p1;
int16_t par_p2;
int8_t par_p3;
int16_t par_p4;
int16_t par_p5;
int8_t par_p6;
int8_t par_p7;
int16_t par_p8;
int16_t par_p9;
uint8_t par_p10;
int16_t par_p2;
int8_t par_p3;
int16_t par_p4;
int16_t par_p5;
int8_t par_p6;
int8_t par_p7;
int16_t par_p8;
int16_t par_p9;
uint8_t par_p10;
/* humidity calibration */
uint16_t par_h1;
uint16_t par_h2;
int8_t par_h3;
int8_t par_h4;
int8_t par_h5;
uint8_t par_h6;
int8_t par_h7;
int8_t par_h3;
int8_t par_h4;
int8_t par_h5;
uint8_t par_h6;
int8_t par_h7;
/* gas maybe */
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;
struct bme680_config {
uint8_t osrs_t;
uint8_t osrs_p;
uint8_t osrs_h;
uint8_t fir;
uint8_t heater_setpoint[10];
uint8_t heater_exposure_ms[10];
uint8_t heater_exposure_scalar[10];
};
double temp_comp_double;
int temp_comp_int;
struct bme680_comp_float {
double tfine;
double temp;
double press;
double hum;
};
double press_comp_double;
int press_comp_int;
struct bme680_comp_int {
int32_t tfine;
int32_t temp;
int32_t press;
int32_t hum;
};
double hum_comp_double;
int hum_comp_int;
struct bme680_adc {
uint32_t temp;
uint32_t press;
uint32_t hum;
uint16_t gas;
};
bme680_calibration cal;
struct bme680 {
struct bme680_comp_float fcomp;
struct bme680_comp_int icomp;
struct bme680_cal cal;
struct bme680_dev dev;
struct bme680_config cfg;
struct bme680_adc adc;
uint8_t mode;
};
} bme680_t;
typedef struct bme680 bme680_t;
int bme680_init(bme680_t *bme680);
int bme680_calibrate(bme680_t *bme680);
void print_calibration(bme680_calibration *);
int bme680_calibrate(int, bme680_calibration *);
int calc_hum_comp_2(uint32_t, bme680_t *);
int calc_press_comp_2(uint32_t, bme680_t *);
int calc_temp_comp_2(uint32_t, bme680_t *);
double calc_temp_comp_1(uint32_t, bme680_t*);
double calc_press_comp_1(uint32_t, bme680_t *);
double calc_hum_comp_1(uint32_t, bme680_t *);
#endif

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main.c
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#define _DEFAULT_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "bme680.h"
#include "i2c.h"
#define DEVICE "/dev/i2c-1"
#define ADDRESS 0x77
int i2c_dev_fd;
int linux_i2c_init (void);
int linux_i2c_read (uint8_t reg, uint8_t *dst, uint32_t size);
int linux_i2c_write (uint8_t reg, uint8_t *src, uint32_t size);
int linux_i2c_deinit (void);
int main(){
int fd = i2c_init(DEVICE, ADDRESS);
bme680_t bme680;
printf("%X\n", i2c_read_reg2(fd, 0xD0));
if (bme680_calibrate(fd, &bme680.cal) != 0) {
fprintf(stderr, "error bme680 calibration\n");
} else {
print_calibration(&bme680.cal);
}
/* 1. Assign functions for interacting with the device */
bme680.dev.init = linux_i2c_init;
bme680.dev.read = linux_i2c_read;
bme680.dev.write = linux_i2c_write;
bme680.dev.deinit = linux_i2c_deinit;
bme680.dev.xfer = NULL;
/* 2. set the device mode */
bme680.mode = BME680_MODE_FLOAT | BME680_I2C;
/* BME680_MODE_INT | BME680_SPI; */
//1. write osrs fields to diff regs
uint8_t ctrl_meas, ctrl_hum;
uint8_t osrs_t, osrs_p, osrs_h, ctrl_mode;
osrs_t = osrs_p = osrs_h = 0b110;
ctrl_mode = 0;
ctrl_meas = (osrs_t << 5) | (osrs_p << 2) | ctrl_mode;
ctrl_hum = osrs_h;
i2c_write_reg(fd, 0x74, ctrl_meas);
i2c_write_reg(fd, 0x72, ctrl_hum);
// set filter mode
uint8_t filter_reg = 0b101 << 2;
i2c_write_reg(fd, 0x75, filter_reg);
// todo gas stuff
// resend ctrl_meas but with ctrl_mode set to 0b01 in it, then it should work
ctrl_meas |= 1;
i2c_write_reg(fd, 0x74, ctrl_meas);
// poll reg `meas_status_0 bit 5. It will be 0 when all scheduled conversions are done.
uint8_t qq;
while ((qq = i2c_read_reg2(fd, 0x1D)) >> 4) {
usleep(2000); // 2 ms
/* 3. initialise device, and check its id */
if (bme680_init(&bme680) != 0) {
fprintf(stderr, "bme680_init()\n");
exit(EXIT_FAILURE);
}
// now read the temp/press/hum adc and convert in order.
uint32_t temp_adc, press_adc, hum_adc;
/* 4. read calibration parameters from the device and store in memory */
if (bme680_calibrate(&bme680) != 0) {
fprintf(stderr, "bme680_calibrate()\n");
bme680.dev.deinit();
exit(EXIT_FAILURE);
}
/* 5. set up device config */
bme680.cfg.osrs_t = BME680_OVERSAMPLE_16X;
bme680.cfg.osrs_p = BME680_OVERSAMPLE_8X;
bme680.cfg.osrs_h = BME680_OVERSAMPLE_4X;
uint8_t buffer[3];
i2c_read_reg(fd, 0x22, 3, buffer);
temp_adc = (buffer[0] << 12) | (buffer[1] << 4) | (buffer[2] >> 4);
i2c_read_reg(fd, 0x1F, 3, buffer);
press_adc = (buffer[0] << 12) | (buffer[1] << 4) | (buffer[2] >> 4);
i2c_read_reg(fd, 0x25, 2, buffer);
hum_adc = (buffer[0] << 8) | buffer[1];
// adc readings are only 20-bit when the IIR filter is enabled, otherwise
// the size depends on the oversample settings (osrs_X).
double temperature = calc_temp_comp_1 ( temp_adc , &bme680 );
printf("temperature: %g oC (floating-point)\n", temperature);
int temperature2 = calc_temp_comp_2 (temp_adc, &bme680 );
printf("temperature: %d oC (integer x100)\n", temperature2);
double pressure = calc_press_comp_1 ( press_adc , &bme680 );
printf("pressure: %g Pa or %g bar (floating-point)\n", pressure, pressure/1e5);
int pressure2 = calc_press_comp_2 (press_adc , &bme680 );
printf("pressure: %d Pa (integer)\n", pressure2);
double humidity = calc_hum_comp_1 ( hum_adc, &bme680 );
printf("humidity: %g (floating-point)\n", humidity);
int humidity2 = calc_hum_comp_2 ( hum_adc, &bme680 );
printf("humidity: %d (integer x1000)\n", humidity2);
close(fd);
return 0;
}
// STUBS
int linux_i2c_init (void) {
puts("linux_i2c_init");
int ret = i2c_init(DEVICE, ADDRESS);
if (ret > 0) {
i2c_dev_fd = ret;
return 0;
}
return 1;
}
int linux_i2c_read (uint8_t reg, uint8_t *dst, uint32_t size) {
puts("linux_i2c_read");
if (i2c_read_reg(i2c_dev_fd, reg, (uint8_t)size, dst) != 0) {
printf("panic read: %d %p %d\n", reg, dst, size);
return 1;
}
return 0;
}
int linux_i2c_write (uint8_t reg, uint8_t *src, uint32_t size) {
puts("linux_i2c_write");
if (i2c_write_reg(i2c_dev_fd, reg, *src) != 0) {
puts("panic!");
return 1;
}
return 0;
}
int linux_i2c_deinit (void) {
close(i2c_dev_fd);
return 0;
}

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#ifndef REGISTERS_H
#define REGISTERS_H
#define REG_SPI_PAGE(v) ((v > 0x7F) ? 0 : 1)
#define REG_STATUS 0x73
#define REG_RESET 0xE0
#define REG_ID 0xD0
#define REG_CONFIG 0x75
#define REG_CTRL_MEAS 0x74
#define REG_CTRL_HUM 0x72
#define REG_CTRL_GAS_1 0x71
#define REG_CTRL_GAS_0 0x70
#define REG_GAS_WAIT_9 0x6D
#define REG_GAS_WAIT_8 0x6C
#define REG_GAS_WAIT_7 0x6B
#define REG_GAS_WAIT_6 0x6A
#define REG_GAS_WAIT_5 0x69
#define REG_GAS_WAIT_4 0x68
#define REG_GAS_WAIT_3 0x67
#define REG_GAS_WAIT_2 0x66
#define REG_GAS_WAIT_1 0x65
#define REG_GAS_WAIT_0 0x64
#define REG_RES_HEAT_9 0x63
#define REG_RES_HEAT_8 0x62
#define REG_RES_HEAT_7 0x61
#define REG_RES_HEAT_6 0x60
#define REG_RES_HEAT_5 0x5F
#define REG_RES_HEAT_4 0x5E
#define REG_RES_HEAT_3 0x5D
#define REG_RES_HEAT_2 0x5C
#define REG_RES_HEAT_1 0x5B
#define REG_RES_HEAT_0 0x5A
#define REG_IDAC_HEAT_9 0x59
#define REG_IDAC_HEAT_8 0x58
#define REG_IDAC_HEAT_7 0x57
#define REG_IDAC_HEAT_6 0x56
#define REG_IDAC_HEAT_5 0x55
#define REG_IDAC_HEAT_4 0x54
#define REG_IDAC_HEAT_3 0x53
#define REG_IDAC_HEAT_2 0x52
#define REG_IDAC_HEAT_1 0x51
#define REG_IDAC_HEAT_0 0x50
#define REG_GAS_R_LSB 0x2B
#define REG_GAS_R_MSB 0x2A
#define REG_HUM_LSB 0x26
#define REG_HUM_MSB 0x25
#define REG_TEMP_XLSB 0x24
#define REG_TEMP_LSB 0x23
#define REG_TEMP_MSB 0x22
#define REG_PRESS_XLSB 0x21
#define REG_PRESS_LSB 0x20
#define REG_PRESS_MSB 0x1F
#define REG_EAS_STATUS 0x1D
#endif