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everything works (gas not attempted yet)

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R.P.Clark 2023-09-18 16:32:27 +01:00
parent 3fef485f97
commit aef3e4c4f9
4 changed files with 69 additions and 58 deletions
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26
README.md
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@ -1,6 +1,6 @@
# bme680 # bme680
Temperature OK, humidity OK, pressure a bit wonky. Not sure why ! Example with working temperature, pressure and humidity readout
``` ```
$ ./bme680 $ ./bme680
@ -9,26 +9,26 @@ par_t1: 26203
par_t2: 26519 par_t2: 26519
par_t3: 3 par_t3: 3
par_p1: 35008 par_p1: 35008
par_p2: 55252 par_p2: -10284
par_p3: 88 par_p3: 88
par_p4: 9692 par_p4: 9692
par_p5: 65334 par_p5: -202
par_p6: 30 par_p6: 30
par_p7: 24 par_p7: 24
par_p8: 65020 par_p8: -516
par_p9: 62067 par_p9: -3469
par_p10: 30 par_p10: 30
par_h1: 794 par_h1: 794
par_h2: 4003 par_h2: 1007
par_h3: 0 par_h3: 0
par_h4: 45 par_h4: 45
par_h5: 20 par_h5: 20
par_h6: 120 par_h6: 120
par_h7: 156 par_h7: -100
temperature: 22.8591 oC (floating-point) temperature: 22.7519 oC (floating-point)
temperature: 2286 oC (integer) temperature: 2275 oC (integer x100)
pressure: 146510 Pa (floating-point) pressure: 99711.8 Pa or 0.997118 bar (floating-point)
pressure: 60428 Pa (integer) pressure: 99708 Pa (integer)
humidity: 639.392 (floating-point) humidity: 62.3145 (floating-point)
humidity: 639001 (integer) humidity: 62289 (integer x1000)
``` ```

48
bme680.c
View File

@ -121,19 +121,22 @@ double calc_press_comp_1 ( uint32_t press_adc , bme680_t *bme680 ) {
cal = &bme680->cal; cal = &bme680->cal;
var1 = (bme680->tfine_double / 2.0) - 64000.0; var1 = ((double)bme680->tfine_int / 2.0) - 64000.0;
var2 = var1 * var1 * ((double)cal->par_p6 / 131072.0); var2 = var1 * var1 * ((double)cal->par_p6 / 131072.0);
var2 = var2 + (var1 * (double)cal->par_p5 * 2.0); var2 = var2 + (var1 * (double)cal->par_p5 * 2.0);
var2 = (var2 / 4.0) + ((double)cal->par_p4 * 65536.0); var2 = (var2 / 4.0) + ((double)cal->par_p4 * 65536.0);
var1 = ((((double)cal->par_p3 * var1 * var1) / 16384.0) + var1 = ((((double)cal->par_p3 * var1 * var1) / 16384.0) +
((double)cal->par_p2 * var1)) / 524288.0; ((double)cal->par_p2 * var1)) / 524288.0;
var1 = (1.0 + (var1 / 32768.0)) * (double)cal->par_p1; var1 = (1.0 + (var1 / 32768.0)) * (double)cal->par_p1;
press_comp = 1048576.0 - (double)press_adc; press_comp = 1048576.0 - (double)press_adc;
press_comp = ((press_comp - (var2 / 4096.0)) * 6250.0) / var1; press_comp = ((press_comp - (var2 / 4096.0)) * 6250.0) / var1;
var1 = ((double)cal->par_p9 * press_comp * press_comp) / 2147483648.0; var1 = ((double)cal->par_p9 * press_comp * press_comp) / 2147483648.0;
var2 = press_comp * ((double)cal->par_p8 / 32768.0); 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); 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; press_comp = press_comp + (var1 + var2 + var3 + ((double)cal->par_p7 * 128.0)) / 16.0;
bme680->press_comp_double = press_comp; bme680->press_comp_double = press_comp;
return press_comp; return press_comp;
} }
@ -141,7 +144,7 @@ double calc_press_comp_1 ( uint32_t press_adc , bme680_t *bme680 ) {
int calc_press_comp_2 ( uint32_t press_adc , bme680_t *bme680 ) { int calc_press_comp_2 ( uint32_t press_adc , bme680_t *bme680 ) {
uint32_t var1, var2, var3, press_comp; int32_t var1, var2, var3, press_comp;
bme680_calibration *cal; bme680_calibration *cal;
cal = &bme680->cal; cal = &bme680->cal;
@ -151,22 +154,23 @@ int calc_press_comp_2 ( uint32_t press_adc , bme680_t *bme680 ) {
var2 = var2 + ((var1 * (int32_t)cal->par_p5) << 1); var2 = var2 + ((var1 * (int32_t)cal->par_p5) << 1);
var2 = (var2 >> 2) + ((int32_t)cal->par_p4 << 16); var2 = (var2 >> 2) + ((int32_t)cal->par_p4 << 16);
var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) * var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
((int32_t)cal->par_p3 << 5)) >> 3) + (((int32_t)cal->par_p2 * var1) >> 1); ((int32_t)cal->par_p3 << 5)) >> 3) + (((int32_t)cal->par_p2 * var1) >> 1);
var1 = var1 >> 18; var1 = var1 >> 18;
var1 = ((32768 + var1) * (int32_t)cal->par_p1) >> 15; var1 = ((32768 + var1) * (int32_t)cal->par_p1) >> 15;
press_comp = 1048576 - press_adc; // says "press_raw" in the bosch example press_comp = 1048576 - press_adc; // bosch code pg 19 says "press_raw" here ???
press_comp = (uint32_t)((press_comp - (var2 >> 12)) * ((uint32_t)3125)); press_comp = (uint32_t)((press_comp - (var2 >> 12)) * ((uint32_t)3125));
if (press_comp >= (1 << 30)) if (press_comp >= (1 << 30))
press_comp = ((press_comp / (uint32_t)var1) << 1); press_comp = ((press_comp / (uint32_t)var1) << 1);
else else
press_comp = ((press_comp << 1) / (uint32_t)var1); press_comp = ((press_comp << 1) / (uint32_t)var1);
var1 = ((int32_t)cal->par_p9 * (int32_t)(((press_comp >> 3) * var1 = ((int32_t)cal->par_p9 * (int32_t)(((press_comp >> 3) *
(press_comp >> 3)) >> 13)) >> 12; (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)cal->par_p8) >> 13;
var3 = ((int32_t)(press_comp >> 8) * (int32_t)(press_comp >> 8) * var3 = ((int32_t)(press_comp >> 8) * (int32_t)(press_comp >> 8) *
(int32_t)(press_comp >> 8) * (int32_t)cal->par_p10) >> 17; (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); press_comp = (int32_t)(press_comp) + ((var1 + var2 + var3 + ((int32_t)cal->par_p7 << 7)) >> 4);
bme680->press_comp_int = press_comp; bme680->press_comp_int = press_comp;
return press_comp; return press_comp;
@ -175,17 +179,20 @@ int calc_press_comp_2 ( uint32_t press_adc , bme680_t *bme680 ) {
double calc_hum_comp_1 ( uint32_t hum_adc , bme680_t *bme680 ) { double calc_hum_comp_1 ( uint32_t hum_adc , bme680_t *bme680 ) {
double var1, var2, var3, var4, hum_comp; double var1, var2, var3, var4, hum_comp, temp_comp;
bme680_calibration *cal; 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)); cal = &bme680->cal;
temp_comp = bme680->temp_comp_double;
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) * 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) * temp_comp) + (((double)cal->par_h5 / 1048576.0) * temp_comp * temp_comp)));
bme680->temp_comp_double * bme680->temp_comp_double)));
var3 = (double)cal->par_h6 / 16384.0; var3 = (double)cal->par_h6 / 16384.0;
var4 = (double)cal->par_h7 / 2097152.0; var4 = (double)cal->par_h7 / 2097152.0;
hum_comp = var2 + ((var3 + (var4 * bme680->temp_comp_double)) * var2 * var2); hum_comp = var2 + ((var3 + (var4 * temp_comp)) * var2 * var2);
bme680->hum_comp_double = hum_comp; bme680->hum_comp_double = hum_comp;
return hum_comp; return hum_comp;
} }
@ -193,24 +200,25 @@ double calc_hum_comp_1 ( uint32_t hum_adc , bme680_t *bme680 ) {
int calc_hum_comp_2 ( uint32_t hum_adc , bme680_t *bme680 ) { int calc_hum_comp_2 ( uint32_t hum_adc , bme680_t *bme680 ) {
uint32_t var1, var2, var3, var4, var5, var6, temp_scaled, hum_comp; int32_t var1, var2, var3, var4, var5, var6, temp_scaled, hum_comp;
bme680_calibration *cal; bme680_calibration *cal;
cal = &bme680->cal; cal = &bme680->cal;
temp_scaled = (int32_t)(bme680->temp_comp_int); temp_scaled = (int32_t)bme680->temp_comp_int;
var1 = (int32_t)hum_adc - (int32_t)((int32_t)cal->par_h1 << 4) - var1 = (int32_t)hum_adc - (int32_t)((int32_t)cal->par_h1 << 4) -
(((temp_scaled * (int32_t)cal->par_h3) / ((int32_t)100)) >> 1); (((temp_scaled * (int32_t)cal->par_h3) / ((int32_t)100)) >> 1);
var2 = ((int32_t)cal->par_h2 * (((temp_scaled * var2 = ((int32_t)cal->par_h2 * (((temp_scaled * (int32_t)cal->par_h4) / ((int32_t)100)) +
(int32_t)cal->par_h4) / ((int32_t)100)) +
(((temp_scaled * ((temp_scaled * (int32_t)cal->par_h5) / (((temp_scaled * ((temp_scaled * (int32_t)cal->par_h5) /
((int32_t)100))) >> 6) / ((int32_t)100)) + ((int32_t)(1 << 14)))) >> 10; ((int32_t)100))) >> 6) / ((int32_t)100)) + ((int32_t)(1 << 14)))) >> 10;
var3 = var1 * var2; var3 = var1 * var2;
var4 = (((int32_t)cal->par_h6 << 7) + var4 = (((int32_t)cal->par_h6 << 7) +
((temp_scaled * (int32_t)cal->par_h7) / ((int32_t)100))) >> 4; ((temp_scaled * (int32_t)cal->par_h7) / ((int32_t)100))) >> 4;
var5 = ((var3 >> 14) * (var3 >> 14)) >> 10; var5 = ((var3 >> 14) * (var3 >> 14)) >> 10;
var6 = (var4 * var5) >> 1; var6 = (var4 * var5) >> 1;
hum_comp = (((var3 + var6) >> 10) * ((int32_t)1000)) >> 12; hum_comp = (((var3 + var6) >> 10) * ((int32_t) 1000)) >> 12;
bme680->hum_comp_int = hum_comp; bme680->hum_comp_int = hum_comp;
return hum_comp; return hum_comp;
} }
@ -269,7 +277,7 @@ int bme680_calibrate ( int fd , bme680_calibration *cal ) {
cal->par_h1 = (buffer[1] << 4) | (buffer[0] & 0xF); cal->par_h1 = (buffer[1] << 4) | (buffer[0] & 0xF);
err |= i2c_read_reg(fd, 0xE1, 2, buffer); err |= i2c_read_reg(fd, 0xE1, 2, buffer);
cal->par_h2 = (buffer[1] << 4) | ((buffer[0] >> 4) & 0xF); cal->par_h2 = (buffer[0] << 4) | ((buffer[1] >> 4) & 0xF);
err |= i2c_read_reg(fd, 0xE4, 1, buffer); err |= i2c_read_reg(fd, 0xE4, 1, buffer);
cal->par_h3 = buffer[0]; cal->par_h3 = buffer[0];

41
bme680.h
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@ -3,26 +3,30 @@
#include <stdint.h> #include <stdint.h>
typedef struct { typedef struct {
uint16_t par_t1; uint16_t par_t1;
uint16_t par_t2; int16_t par_t2;
uint16_t par_t3; // 8 bit word int8_t par_t3;
uint16_t par_p1; uint16_t par_p1;
uint16_t par_p2; int16_t par_p2;
uint16_t par_p3; // 8 bit word int8_t par_p3;
uint16_t par_p4; int16_t par_p4;
uint16_t par_p5; int16_t par_p5;
uint16_t par_p6; // 8 bit word int8_t par_p6;
uint16_t par_p7; // 8 bit word int8_t par_p7;
uint16_t par_p8; int16_t par_p8;
uint16_t par_p9; int16_t par_p9;
uint16_t par_p10; //8 bit word uint8_t par_p10;
uint16_t par_h1; uint16_t par_h1;
uint16_t par_h2; uint16_t par_h2;
uint16_t par_h3; int8_t par_h3;
uint16_t par_h4; int8_t par_h4;
uint16_t par_h5; int8_t par_h5;
uint16_t par_h6; uint8_t par_h6;
uint16_t par_h7; int8_t par_h7;
uint16_t par_g1; uint16_t par_g1;
uint16_t par_g2; uint16_t par_g2;
uint16_t par_g3; uint16_t par_g3;
@ -52,10 +56,9 @@ typedef struct {
void print_calibration(bme680_calibration *); void print_calibration(bme680_calibration *);
int bme680_calibrate(int, bme680_calibration *); int bme680_calibrate(int, bme680_calibration *);
int calc_hum_comp_2(uint32_t, bme680_t *); int calc_hum_comp_2(uint32_t, bme680_t *);
double calc_hum_comp_1(uint32_t, bme680_t *);
int calc_press_comp_2(uint32_t, bme680_t *); int calc_press_comp_2(uint32_t, bme680_t *);
double calc_press_comp_1(uint32_t, bme680_t *);
int calc_temp_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_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 *);

8
main.c
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@ -24,7 +24,7 @@ int main(){
uint8_t ctrl_meas, ctrl_hum; uint8_t ctrl_meas, ctrl_hum;
uint8_t osrs_t, osrs_p, osrs_h, ctrl_mode; uint8_t osrs_t, osrs_p, osrs_h, ctrl_mode;
osrs_t = osrs_p = osrs_h = 0b011; osrs_t = osrs_p = osrs_h = 0b110;
ctrl_mode = 0; ctrl_mode = 0;
ctrl_meas = (osrs_t << 5) | (osrs_p << 2) | ctrl_mode; ctrl_meas = (osrs_t << 5) | (osrs_p << 2) | ctrl_mode;
@ -72,11 +72,11 @@ int main(){
printf("temperature: %g oC (floating-point)\n", temperature); printf("temperature: %g oC (floating-point)\n", temperature);
int temperature2 = calc_temp_comp_2 (temp_adc, &bme680 ); int temperature2 = calc_temp_comp_2 (temp_adc, &bme680 );
printf("temperature: %d oC (integer)\n", temperature2); printf("temperature: %d oC (integer x100)\n", temperature2);
double pressure = calc_press_comp_1 ( press_adc , &bme680 ); double pressure = calc_press_comp_1 ( press_adc , &bme680 );
printf("pressure: %g Pa (floating-point)\n", pressure); printf("pressure: %g Pa or %g bar (floating-point)\n", pressure, pressure/1e5);
int pressure2 = calc_press_comp_2 (press_adc , &bme680 ); int pressure2 = calc_press_comp_2 (press_adc , &bme680 );
printf("pressure: %d Pa (integer)\n", pressure2); printf("pressure: %d Pa (integer)\n", pressure2);
@ -85,7 +85,7 @@ int main(){
printf("humidity: %g (floating-point)\n", humidity); printf("humidity: %g (floating-point)\n", humidity);
int humidity2 = calc_hum_comp_2 ( hum_adc, &bme680 ); int humidity2 = calc_hum_comp_2 ( hum_adc, &bme680 );
printf("humidity: %d (integer)\n", humidity2); printf("humidity: %d (integer x1000)\n", humidity2);
close(fd); close(fd);
return 0; return 0;