diff --git a/Makefile b/Makefile
index fd97cd9..7534cf2 100644
--- a/Makefile
+++ b/Makefile
@@ -1,2 +1,2 @@
 all:
-	gcc -O2 -std=c99 -Wall -Wextra main.c bme680.c i2c.c -o bme680
+	gcc -O2 -std=gnu99 -Wall -Wextra main.c bme680.c i2c.c -o bme680
diff --git a/README.md b/README.md
index 520ca8b..dd19efd 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,34 @@
 # bme680
-test
+
+Temperature OK, humidity OK, pressure a bit wonky. Not sure why !
+
+```
+$ ./bme680
+61
+par_t1: 26203
+par_t2: 26519
+par_t3: 3
+par_p1: 35008
+par_p2: 55252
+par_p3: 88
+par_p4: 9692
+par_p5: 65334
+par_p6: 30
+par_p7: 24
+par_p8: 65020
+par_p9: 62067
+par_p10: 30
+par_h1: 794
+par_h2: 4003
+par_h3: 0
+par_h4: 45
+par_h5: 20
+par_h6: 120
+par_h7: 156
+temperature: 22.8591 oC (floating-point)
+temperature: 2286 oC (integer)
+pressure: 146510 Pa (floating-point)
+pressure: 60428 Pa (integer)
+humidity: 639.392 (floating-point)
+humidity: 639001 (integer)
+```
diff --git a/bme680.c b/bme680.c
index 6a82552..f2bb6ea 100644
--- a/bme680.c
+++ b/bme680.c
@@ -1,4 +1,6 @@
 #include "bme680.h"
+#include "i2c.h"
+#include <stdio.h>
 
 const double const_array1[16] = {
 	1,
@@ -77,7 +79,7 @@ const int const_array2_int[16] = {
 };
 
 
-static double calc_temp_comp_1 ( uint32_t temp_adc , bme680_t *bme680) {
+double calc_temp_comp_1 ( uint32_t temp_adc , bme680_t *bme680) {
 
 	double var1, var2, temp_comp;
 	bme680_calibration *cal;
@@ -96,7 +98,7 @@ static double calc_temp_comp_1 ( uint32_t temp_adc , bme680_t *bme680) {
 	return temp_comp;
 }
 
-static int calc_temp_comp_2 (uint32_t temp_adc, bme680_t *bme680) {
+int calc_temp_comp_2 (uint32_t temp_adc, bme680_t *bme680) {
 
 	int32_t var1, var2, var3, temp_comp;
 	bme680_calibration *cal;
@@ -112,7 +114,7 @@ static int calc_temp_comp_2 (uint32_t temp_adc, bme680_t *bme680) {
 	return temp_comp;
 }
 
-static double calc_press_comp_1 ( uint32_t press_adc  ,  bme680_t *bme680 ) {
+double calc_press_comp_1 ( uint32_t press_adc  ,  bme680_t *bme680 ) {
 
 	double var1, var2, var3, press_comp;
 	bme680_calibration *cal;
@@ -137,7 +139,7 @@ static double calc_press_comp_1 ( uint32_t press_adc  ,  bme680_t *bme680 ) {
 }
 
 
-static 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;
 	bme680_calibration *cal;
@@ -171,7 +173,7 @@ static int calc_press_comp_2  ( uint32_t press_adc ,  bme680_t *bme680 )  {
 
 }
 
-static 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;
 	bme680_calibration *cal;
@@ -189,7 +191,7 @@ static double calc_hum_comp_1  ( uint32_t hum_adc  ,   bme680_t *bme680 ) {
 }
 
 
-static 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;
 	bme680_calibration *cal;
@@ -213,5 +215,114 @@ static int calc_hum_comp_2  (  uint32_t hum_adc  ,  bme680_t *bme680 ) {
 	return hum_comp;
 }
 
+int bme680_calibrate ( int fd , bme680_calibration *cal ) {
+
+	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 |= i2c_read_reg(fd, 0x8A, 2, buffer);
+	cal->par_t2 = (buffer[1] << 8) | buffer[0];
+
+	err |= i2c_read_reg(fd, 0x8C, 1, buffer);
+	cal->par_t3 = buffer[0];
+
+	// pressure
+	
+	err |= i2c_read_reg(fd, 0x8E, 2, buffer);
+	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 |= i2c_read_reg(fd, 0x92, 1, buffer);
+	cal->par_p3 = buffer[0];
+
+	err |= i2c_read_reg(fd, 0x94, 2, buffer);
+	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 |= i2c_read_reg(fd, 0x99, 1, buffer);
+	cal->par_p6 = buffer[0];
+
+	err |= i2c_read_reg(fd, 0x98, 1, buffer); // strange order
+	cal->par_p7 = buffer[0];
+
+	err |= i2c_read_reg(fd, 0x9C, 2, buffer);
+	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 |= i2c_read_reg(fd, 0xA0, 1, buffer);
+	cal->par_p10 = buffer[0];
+
+	// humidity
+	
+	err |= i2c_read_reg(fd, 0xE2, 2, buffer);
+	cal->par_h1 = (buffer[1] << 4) | (buffer[0] & 0xF);
+
+	err |= i2c_read_reg(fd, 0xE1, 2, buffer);
+	cal->par_h2 = (buffer[1] << 4) | ((buffer[0] >> 4) & 0xF);
+
+	err |= i2c_read_reg(fd, 0xE4, 1, buffer);
+	cal->par_h3 = buffer[0];
+
+	err |= i2c_read_reg(fd, 0xE5, 1, buffer);
+	cal->par_h4 = buffer[0];
+
+	err |= i2c_read_reg(fd, 0xE6, 1, buffer);
+	cal->par_h5 = buffer[0];
+
+	err |= i2c_read_reg(fd, 0xE7, 1, buffer);
+	cal->par_h6 = buffer[0];
+
+	err |= i2c_read_reg(fd, 0xE8, 1, buffer);
+	cal->par_h7 = buffer[0];
+
+	// gas
+	
+	err |= i2c_read_reg(fd, 0xED, 1, buffer);
+	cal->par_g1 = buffer[0];
+
+	err |= i2c_read_reg(fd, 0xEB, 2, buffer);
+	cal->par_g2 = (buffer[1] << 8) | buffer[0];
+
+	err |= i2c_read_reg(fd, 0xEE, 1, buffer);
+	cal->par_g2 = buffer[0];
+
+	//  todo more
 
 
+
+	return err;
+}
+
+void print_calibration  ( bme680_calibration *cal ) {
+	printf("par_t1: %d\n", cal->par_t1);
+	printf("par_t2: %d\n", cal->par_t2);
+	printf("par_t3: %d\n", cal->par_t3);
+	printf("par_p1: %d\n", cal->par_p1);
+	printf("par_p2: %d\n", cal->par_p2);
+	printf("par_p3: %d\n", cal->par_p3);
+	printf("par_p4: %d\n", cal->par_p4);
+	printf("par_p5: %d\n", cal->par_p5);
+	printf("par_p6: %d\n", cal->par_p6);
+	printf("par_p7: %d\n", cal->par_p7);
+	printf("par_p8: %d\n", cal->par_p8);
+	printf("par_p9: %d\n", cal->par_p9);
+	printf("par_p10: %d\n", cal->par_p10);
+	printf("par_h1: %d\n", cal->par_h1);
+	printf("par_h2: %d\n", cal->par_h2);
+	printf("par_h3: %d\n", cal->par_h3);
+	printf("par_h4: %d\n", cal->par_h4);
+	printf("par_h5: %d\n", cal->par_h5);
+	printf("par_h6: %d\n", cal->par_h6);
+	printf("par_h7: %d\n", cal->par_h7);
+}
diff --git a/bme680.h b/bme680.h
index a11c355..f96c0ed 100644
--- a/bme680.h
+++ b/bme680.h
@@ -46,3 +46,16 @@ typedef struct {
 	bme680_calibration cal;
 
 } bme680_t;
+
+
+
+void print_calibration(bme680_calibration *);
+int bme680_calibrate(int, bme680_calibration *);
+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 *);
+double calc_press_comp_1(uint32_t, bme680_t *);
+int calc_temp_comp_2(uint32_t, bme680_t *);
+double calc_temp_comp_1(uint32_t, bme680_t*);
+
+
diff --git a/i2c.c b/i2c.c
index 4ba058e..0fb19a2 100644
--- a/i2c.c
+++ b/i2c.c
@@ -7,9 +7,6 @@
 #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;
 
@@ -56,22 +53,3 @@ int i2c_write_reg(int fd, uint8_t reg, uint8_t value) {
 	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;
-}
diff --git a/main.c b/main.c
index 235afe1..9251147 100644
--- a/main.c
+++ b/main.c
@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include "bme680.h"
 #include "i2c.h"
+#include <unistd.h>
 
 #define DEVICE "/dev/i2c-1"
 #define ADDRESS 0x77
@@ -8,8 +9,83 @@
 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. 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 = 0b011;
+	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
+	}
+
+	// now read the temp/press/hum adc and convert in order.
+	uint32_t temp_adc, press_adc, hum_adc;
+
+
+	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)\n", temperature2);
+
+
+	double pressure = calc_press_comp_1 ( press_adc  , &bme680 );
+	printf("pressure: %g Pa (floating-point)\n", pressure);
+
+	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)\n", humidity2);
 
 	close(fd);
 	return 0;