change a lot

2024-08-19 14:17:39 +01:00 · 2024-08-19 14:17:39 +01:00 · 23de126d97
commit 23de126d97
parent b3783a13da
15 changed files with 343 additions and 198 deletions
--- a/.gitignore
+++ b/.gitignore
@ -1,2 +1,5 @@
 *.o
-bme680
+bme680
+bme680_i2c
+bme680_spi
+bme680_log*
--- a/41
+++ b/41
@ -1,17 +1,38 @@
 CC=gcc
-OPT=-O2 -std=c99 -Wall -Wextra -W -pedantic
-CFLAGS=-I. $(OPT)
-CFILES=$(wildcard ./*.c)
-OBJECTS=$(patsubst %.c,%.o, $(CFILES))
-BINARY=bme680
+CFLAGS = -g -O0 -Wall -Wextra -Wpedantic -Wshadow -Wformat=2 -Wfloat-equal \
+         -Wconversion -Wcast-align -Wpointer-arith -Wstrict-overflow=5 \
+         -Wwrite-strings -Wcast-qual -Wswitch-default -Wswitch-enum \
+         -Wunreachable-code -Wstrict-prototypes -Wmissing-prototypes \
+         -Wmissing-declarations -Wredundant-decls -Wold-style-definition \
+         -Winline -Wlogical-op -Wjump-misses-init -Wdouble-promotion \
+         -Wformat-overflow=2 -Wformat-signedness -Wmissing-include-dirs \
+         -Wnull-dereference -Wstack-usage=1024 -Wpacked -Woverlength-strings \
+         -Wvla -Walloc-zero -Wduplicated-cond -Wduplicated-branches -Wrestrict \
+         -fanalyzer -I. -std=c89

-all: $(BINARY)
+CFILES = $(wildcard *.c)
+OBJECTS = $(CFILES:.c=.o)
+BIN = bme680

-$(BINARY): $(OBJECTS)
-	$(CC) $^ -o $@
+all: spi i2c
+
+log: $(OBJECTS)
+	@echo ">>> $(BIN)_log_spi"
+	@$(CC) $(CFLAGS) -DUSE_SPI -std=gnu99 $^ cmd/log.c -o "$(BIN)_log_spi"
+	@echo ">>> $(BIN)_log_i2c"
+	@$(CC) $(CFLAGS) -DUSE_I2C -std=gnu99 $^ cmd/log.c -o "$(BIN)_log_i2c"
+
+spi: $(OBJECTS)
+	@echo ">>> $(BIN)_spi"
+	@$(CC) $(CFLAGS) -DUSE_SPI $^ cmd/main.c -o "$(BIN)_spi"
+
+i2c: $(OBJECTS)
+	@echo ">>> $(BIN)_i2c"
+	@$(CC) $(CFLAGS) -DUSE_I2C $^ cmd/main.c -o "$(BIN)_i2c"

 %.o:%.c
-	$(CC) $(CFLAGS) -c $< -o $@
+	@echo "cc $<"
+	@$(CC) $(CFLAGS) -c $< -o $@

 clean:
-	@rm -rf $(OBJECTS) $(BINARY)
+	@rm -rf $(OBJECTS)
--- a/README.md
+++ b/README.md
@ -14,6 +14,11 @@ Connecting the purple BME680 module board to SPI:
 | SCLK     | "SCL"      | GPIO 11 (Pin 23) |
 | CS       | "CS"       | GPIO 8 (Pin 24)  |

+### build
+Run `make` to build demo programs `bme680_spi` and `bme680_i2c` that use the pins/dev configured in `spi.c` and `i2c.c`
+
+Also `make log` creates spi and i2c versions of the log program
+
 ## spi demo
 ```
 par_t1: 26203
--- a/bme680.c
+++ b/bme680.c
@ -1,8 +1,6 @@
 #include <stdio.h>

 #include "bme680.h"
-#include "registers.h"
-

 static void calc_temp_comp(bme680_t *bme680);
 static void calc_press_comp(bme680_t *bme680);
@ -152,9 +150,9 @@ int bme680_reset(bme680_t *bme680) {
 /********************************************************************/
 /* configure device */
 int bme680_configure(bme680_t *bme680) {
-	uint8_t meas, hum, filter, ctrl_gas1, ctrl_gas0, err;
-	int i;
-	meas = hum = filter = err = 0;
+	uint8_t meas, hum, filter, ctrl_gas1, ctrl_gas0, i;
+	int err = 0;
+	meas = hum = filter = 0;

 	/* ctrl_meas. the last 0 is ticked on to enable forced mode,
 	 * but the config has to be written first. strange behaviour.
@ -299,12 +297,14 @@ static int const_array1_int[16] = {
 	2147483647
 };

-/* long int maybe */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Woverflow"
 static int const_array2_int[16] = {
 	4096000000, 2048000000, 1024000000, 512000000, 255744255,
 	127110228, 64000000, 32258064, 16016016, 8000000, 4000000,
 	2000000, 1000000, 500000, 250000, 125000
 };
+#pragma GCC diagnostic pop

 /********************************************************************/
 /********************************************************************/
@ -364,6 +364,8 @@ static void calc_press_comp_1 (bme680_t *bme680) {
 }

 /********************************************************************/
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-conversion"
 static void calc_press_comp_2 (bme680_t *bme680 )  {
 	int32_t var1, var2, var3, press_comp;

@ -375,7 +377,7 @@ static void calc_press_comp_2 (bme680_t *bme680 )  {
 			((int32_t)bme680->cal.par_p3 << 5)) >> 3) +  (((int32_t)bme680->cal.par_p2 * var1) >> 1);
 	var1 = var1 >> 18;
 	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 = 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);
@ -389,6 +391,7 @@ static void calc_press_comp_2 (bme680_t *bme680 )  {
 	press_comp = (int32_t)(press_comp) + ((var1 + var2 + var3 + ((int32_t)bme680->cal.par_p7 << 7)) >> 4);
 	bme680->icomp.press = press_comp;
 }
+#pragma GCC diagnostic pop

 /********************************************************************/
 static void calc_press_comp (bme680_t *bme680) {
@ -445,7 +448,7 @@ static void calc_hum_comp (bme680_t *bme680) {
 }

 /********************************************************************/
-// TODO: read one big contiguous block
+/* TODO: read one big contiguous block */
 int bme680_calibrate(bme680_t *bme680) {
 	uint8_t buffer[3] = {0, 0 ,0};
 	int err = 0;
@ -458,7 +461,7 @@ int bme680_calibrate(bme680_t *bme680) {
 	bme680->cal.par_t2 = (buffer[1] << 8) | buffer[0];

 	err |= read_dev(bme680, 0x8C, buffer, 1);
-	bme680->cal.par_t3 = buffer[0];
+	bme680->cal.par_t3 = (int8_t)buffer[0];


 	/* pressure */
@ -469,7 +472,7 @@ int bme680_calibrate(bme680_t *bme680) {
 	bme680->cal.par_p2 = (buffer[1] << 8) | buffer[0];

 	err |= read_dev(bme680, 0x92, buffer, 1);
-	bme680->cal.par_p3 = buffer[0];
+	bme680->cal.par_p3 = (int8_t)buffer[0];

 	err |= read_dev(bme680, 0x94, buffer, 2);
 	bme680->cal.par_p4 = (buffer[1] << 8) | buffer[0];
@ -478,10 +481,10 @@ int bme680_calibrate(bme680_t *bme680) {
 	bme680->cal.par_p5 = (buffer[1] << 8) | buffer[0];

 	err |= read_dev(bme680, 0x99, buffer, 1);
-	bme680->cal.par_p6 = buffer[0];
+	bme680->cal.par_p6 = (int8_t)buffer[0];

 	err |= read_dev(bme680, 0x98, buffer, 1);
-	bme680->cal.par_p7 = buffer[0];
+	bme680->cal.par_p7 = (int8_t)buffer[0];

 	err |= read_dev(bme680, 0x9C, buffer, 1);
 	bme680->cal.par_p8 = (buffer[1] << 8) | buffer[0];
@ -501,19 +504,19 @@ int bme680_calibrate(bme680_t *bme680) {
 	bme680->cal.par_h2 = (buffer[0] << 4) | ((buffer[1] >> 4) & 0xF);

 	err |= read_dev(bme680, 0xE4, buffer, 1);
-	bme680->cal.par_h3 = buffer[0];
+	bme680->cal.par_h3 = (int8_t)buffer[0];

 	err |= read_dev(bme680, 0xE5, buffer, 1);
-	bme680->cal.par_h4 = buffer[0];
+	bme680->cal.par_h4 = (int8_t)buffer[0];

 	err |= read_dev(bme680, 0xE6, buffer, 1);
-	bme680->cal.par_h5 = buffer[0];
+	bme680->cal.par_h5 = (int8_t)buffer[0];

 	err |= read_dev(bme680, 0xE7, buffer, 1);
 	bme680->cal.par_h6 = buffer[0];

 	err |= read_dev(bme680, 0xE8, buffer, 1);
-	bme680->cal.par_h7 = buffer[0];
+	bme680->cal.par_h7 = (int8_t)buffer[0];


 	/* gas */	
@ -533,7 +536,7 @@ int bme680_calibrate(bme680_t *bme680) {
 	bme680->cal.res_heat_range = (buffer[0] >> 4) & 3;

 	err |= read_dev(bme680, 0x00, buffer, 1);
-	bme680->cal.res_heat_val = buffer[0];
+	bme680->cal.res_heat_val = (int8_t)buffer[0];

 	return err;
 }
@ -568,35 +571,7 @@ static void calc_gas_res(bme680_t *bme680) {
 	}
 }

-/********************************************************************/
-void bme680_print_calibration (bme680_t *bme680) {
-	printf("par_t1: %d\n", bme680->cal.par_t1);
-	printf("par_t2: %d\n", bme680->cal.par_t2);
-	printf("par_t3: %d\n", bme680->cal.par_t3);
-	printf("par_p1: %d\n", bme680->cal.par_p1);
-	printf("par_p2: %d\n", bme680->cal.par_p2);
-	printf("par_p3: %d\n", bme680->cal.par_p3);
-	printf("par_p4: %d\n", bme680->cal.par_p4);
-	printf("par_p5: %d\n", bme680->cal.par_p5);
-	printf("par_p6: %d\n", bme680->cal.par_p6);
-	printf("par_p7: %d\n", bme680->cal.par_p7);
-	printf("par_p8: %d\n", bme680->cal.par_p8);
-	printf("par_p9: %d\n", bme680->cal.par_p9);
-	printf("par_p10: %d\n", bme680->cal.par_p10);
-	printf("par_h1: %d\n", bme680->cal.par_h1);
-	printf("par_h2: %d\n", bme680->cal.par_h2);
-	printf("par_h3: %d\n", bme680->cal.par_h3);
-	printf("par_h4: %d\n", bme680->cal.par_h4);
-	printf("par_h5: %d\n", bme680->cal.par_h5);
-	printf("par_h6: %d\n", bme680->cal.par_h6);
-	printf("par_h7: %d\n", bme680->cal.par_h7);
-	printf("par_g1: %d\n", bme680->cal.par_g1);
-	printf("par_g2: %d\n", bme680->cal.par_g2);
-	printf("par_g3: %d\n", bme680->cal.par_g3);
-	printf("range_switching_error: %d\n", bme680->cal.range_switching_error);
-	printf("res_heat_range: %d\n", bme680->cal.res_heat_range);
-	printf("res_heat_val: %d\n", bme680->cal.res_heat_val);
-}
+

 /********************************************************************/
 static uint8_t calc_target_1(bme680_t *bme680, double target, double ambient) {
@ -614,6 +589,8 @@ static uint8_t calc_target_1(bme680_t *bme680, double target, double ambient) {
 }

 /********************************************************************/
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wfloat-conversion"
 static uint8_t calc_target_2(bme680_t *bme680, double target, double ambient) {
 	int32_t var1, var2, var3, var4, var5, res_heat_x100;
 	uint8_t res_heat;
@ -628,6 +605,7 @@ static uint8_t calc_target_2(bme680_t *bme680, double target, double ambient) {
 	res_heat = (uint8_t)((res_heat_x100 + 50) / 100);
 	return res_heat;
 }
+#pragma GCC diagnostic pop

 /********************************************************************/
 uint8_t bme680_calc_target(bme680_t *bme680, double target, double ambient) {
--- a/bme680.h
+++ b/bme680.h
@ -3,6 +3,75 @@

 #include <stdint.h>

+/* REGISTERS */
+
+/* confuses me too ! */
+/* SPI page number 0 => 0x00 to 0x7F */
+/* SPI page number 1 => 0x80 to 0xFF */
+#define REG_SPI_PAGE(v) ((v > 0x7F) ? 0 : 1)
+#define REG_SPI_PAGE_MAP(v) (v == 0 ? "LOW" : "HIGH")
+
+#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_MEAS_STATUS 0x1D
+
+/* END OF REGISTERS */
+
 #define BME680_IS_SPI(m)      ((m & 1) == 1)
 #define BME680_IS_FLOAT(m)    (((m >> 1) & 1) == 0)
 #define BME680_GAS_ENABLED(m) (((m >> 2) & 1) == 1) 
@ -142,7 +211,6 @@ struct bme680 {

 typedef struct bme680 bme680_t;

-
 int bme680_init(bme680_t *bme680, uint8_t mode);
 int bme680_deinit(bme680_t *bme680);
 int bme680_reset(bme680_t *bme680);
@ -156,6 +224,4 @@ int bme680_read_setpoint_index(bme680_t *bme680, uint8_t *index);

 uint8_t bme680_calc_target(bme680_t *bme680, double target, double ambient);

-void bme680_print_calibration(bme680_t *bme680);
-
 #endif
--- a/bme680_util.c
+++ b/bme680_util.c
@ -0,0 +1,31 @@
+#include <stdio.h>
+#include "bme680_util.h"
+
+void bme680_print_calibration (bme680_t *bme680) {
+	printf("par_t1: %d\n", bme680->cal.par_t1);
+	printf("par_t2: %d\n", bme680->cal.par_t2);
+	printf("par_t3: %d\n", bme680->cal.par_t3);
+	printf("par_p1: %d\n", bme680->cal.par_p1);
+	printf("par_p2: %d\n", bme680->cal.par_p2);
+	printf("par_p3: %d\n", bme680->cal.par_p3);
+	printf("par_p4: %d\n", bme680->cal.par_p4);
+	printf("par_p5: %d\n", bme680->cal.par_p5);
+	printf("par_p6: %d\n", bme680->cal.par_p6);
+	printf("par_p7: %d\n", bme680->cal.par_p7);
+	printf("par_p8: %d\n", bme680->cal.par_p8);
+	printf("par_p9: %d\n", bme680->cal.par_p9);
+	printf("par_p10: %d\n", bme680->cal.par_p10);
+	printf("par_h1: %d\n", bme680->cal.par_h1);
+	printf("par_h2: %d\n", bme680->cal.par_h2);
+	printf("par_h3: %d\n", bme680->cal.par_h3);
+	printf("par_h4: %d\n", bme680->cal.par_h4);
+	printf("par_h5: %d\n", bme680->cal.par_h5);
+	printf("par_h6: %d\n", bme680->cal.par_h6);
+	printf("par_h7: %d\n", bme680->cal.par_h7);
+	printf("par_g1: %d\n", bme680->cal.par_g1);
+	printf("par_g2: %d\n", bme680->cal.par_g2);
+	printf("par_g3: %d\n", bme680->cal.par_g3);
+	printf("range_switching_error: %d\n", bme680->cal.range_switching_error);
+	printf("res_heat_range: %d\n", bme680->cal.res_heat_range);
+	printf("res_heat_val: %d\n", bme680->cal.res_heat_val);
+}
--- a/bme680_util.h
+++ b/bme680_util.h
@ -0,0 +1,8 @@
+#ifndef BME680_UTIL_H
+#define BME680_UTIL_H
+
+#include "bme680.h"
+
+void bme680_print_calibration (bme680_t *bme680);
+
+#endif
--- a/cmd/log.c
+++ b/cmd/log.c
@ -0,0 +1,120 @@
+#define _DEFAULT_SOURCE 
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <time.h>
+
+#include "bme680.h"
+#include "i2c.h"
+#include "spi.h"
+
+#define AMBIENT_TEMP_GUESS 19.0
+#define HEATER_TARGET 300.0
+
+int main(void) {
+	
+	bme680_t bme680;
+	uint8_t mode;
+	double temperature = AMBIENT_TEMP_GUESS;
+	time_t curr_time;
+	char date[100];
+
+#if defined(USE_SPI) && defined(USE_I2C)
+    #error "Both USE_SPI and USE_I2C are defined. Please define only one."
+#elif !defined(USE_SPI) && !defined(USE_I2C)
+    #error "Neither USE_SPI nor USE_I2C is defined. Please define one."
+#elif defined(USE_SPI)
+    bme680.dev.init   = spi_init;	
+	bme680.dev.read   = spi_read;
+	bme680.dev.write  = spi_write;
+	bme680.dev.deinit = spi_deinit;
+#elif defined(USE_I2C)
+	bme680.dev.init   = i2c_init;	
+	bme680.dev.read   = i2c_read;
+	bme680.dev.write  = i2c_write;
+	bme680.dev.deinit = i2c_deinit;
+#endif
+    bme680.dev.sleep = usleep;
+
+	mode = BME680_MODE_FLOAT | BME680_ENABLE_GAS;
+#if defined(USE_SPI)
+    mode |= BME680_SPI;
+#elif defined(USE_I2C)
+	mode |= BME680_I2C;
+#endif
+
+	if (bme680_init(&bme680, mode) != 0) {
+		fprintf(stderr, "bme680_init()\n");
+		exit(EXIT_FAILURE);
+	}
+
+START:
+    if (bme680_reset(&bme680) != 0) {
+		fprintf(stderr, "bme680_reset()\n");
+        bme680_deinit(&bme680);
+		exit(EXIT_FAILURE);
+	}
+
+	if (bme680_calibrate(&bme680) != 0) {
+		fprintf(stderr, "bme680_calibrate()\n");
+		bme680_deinit(&bme680);
+		exit(EXIT_FAILURE);
+	}
+
+	bme680.cfg.osrs_t = BME680_OVERSAMPLE_X16;
+	bme680.cfg.osrs_p = BME680_OVERSAMPLE_X16;
+	bme680.cfg.osrs_h = BME680_OVERSAMPLE_X8;
+	bme680.cfg.filter = BME680_IIR_COEFF_127;
+
+	bme680.cfg.res_heat[0] = bme680_calc_target(&bme680, HEATER_TARGET, temperature);
+	bme680.cfg.idac_heat[0] = BME680_IDAC(100);
+	bme680.cfg.gas_wait[0] = BME680_GAS_WAIT(25, BME680_GAS_WAIT_X4);
+	
+	bme680.setpoint = 0;
+
+	if (bme680_configure(&bme680) != 0) {
+		fprintf(stderr, "bme680_configure()\n");
+		bme680_deinit(&bme680);
+		exit(EXIT_FAILURE);
+	}
+
+	if (bme680_start(&bme680) != 0) {
+		fprintf(stderr, "bme680_start()\n");
+		bme680_deinit(&bme680);
+		exit(EXIT_FAILURE);
+	}
+
+	if (bme680_poll(&bme680) != 0) {
+		fprintf(stderr, "bme680_poll()\n");
+		bme680_deinit(&bme680);
+		exit(EXIT_FAILURE);
+	}
+
+	if (bme680_read(&bme680) != 0) {
+		fprintf(stderr, "bme680_read()\n");
+		bme680_deinit(&bme680);
+		exit(EXIT_FAILURE);
+	}
+
+	curr_time = time(NULL);
+	strftime(date, 100, "%FT%T%z", localtime(&curr_time));
+	printf("%s %g %g %g %g %d\n",
+			date,
+			bme680.fcomp.temp,
+			bme680.fcomp.press,
+			bme680.fcomp.hum,
+			bme680.fcomp.gas_res,
+			!!bme680.heat_stab);
+
+	temperature = bme680.fcomp.temp;
+
+    /* 60 secs */
+	usleep(1000*1000*60);
+	goto START;
+
+	bme680_deinit(&bme680);
+
+	return 0;
+}
+
--- a/cmd/main.c
+++ b/cmd/main.c
@ -6,6 +6,7 @@
 #include <unistd.h>

 #include "bme680.h"
+#include "bme680_util.h"
 #include "i2c.h"
 #include "spi.h"

@ -20,21 +21,33 @@ int main(void) {

 	/* 1. Assign functions for interacting with the device */

-//	bme680.dev.init   = i2c_init;	
-//	bme680.dev.read   = i2c_read;
-//	bme680.dev.write  = i2c_write;
-//	bme680.dev.deinit = i2c_deinit;
-
-	bme680.dev.init   = spi_init;
+#if defined(USE_SPI) && defined(USE_I2C)
+    #error "Both USE_SPI and USE_I2C are defined. Please define only one."
+#elif !defined(USE_SPI) && !defined(USE_I2C)
+    #error "Neither USE_SPI nor USE_I2C is defined. Please define one."
+#elif defined(USE_SPI)
+    bme680.dev.init   = spi_init;	
 	bme680.dev.read   = spi_read;
 	bme680.dev.write  = spi_write;
 	bme680.dev.deinit = spi_deinit;
+#elif defined(USE_I2C)
+	bme680.dev.init   = i2c_init;	
+	bme680.dev.read   = i2c_read;
+	bme680.dev.write  = i2c_write;
+	bme680.dev.deinit = i2c_deinit;
+#endif
+

 	bme680.dev.sleep  = usleep;

 	/* 2. set the device mode */
-	mode = BME680_MODE_FLOAT | BME680_SPI | BME680_ENABLE_GAS;
-	/*     BME680_MODE_INT   | BME680_I2C; */
+	mode = BME680_MODE_FLOAT | BME680_ENABLE_GAS;
+#if defined(USE_SPI)
+    mode |= BME680_SPI;
+#elif defined(USE_I2C)
+	mode |= BME680_I2C;
+#endif
+


 	/* 3. initialise dev func's, and check device id */
--- a/doc/datasheet.pdf
+++ b/doc/datasheet.pdf
--- a/i2c.c
+++ b/i2c.c
@ -1,8 +1,4 @@
-/* 
-
-Example I2C use on linux/raspberry pi
-
-*/
+/* Raspberry Pi i2c */

 #include <stdio.h>
 #include <fcntl.h>
@ -24,42 +20,47 @@ int i2c_init(void) {
 	fd = open(I2C_DEVICE, O_RDWR);
 	if (fd < 0) {
 		fprintf(stderr, "could not open device: %s\n", I2C_DEVICE);
-		return I2C_ERR;
+		return 1;
 	}

 	if (ioctl(fd, I2C_SLAVE, I2C_BME680_ADDRESS) < 0) {
 		fprintf(stderr, "failed to acquire bus/talk to slave\n");
 		close(fd);
-		return I2C_ERR;
+		return 1;
 	}

-	return I2C_OK;
+	return 0;
 }


 int i2c_read(uint8_t reg, uint8_t *dst, uint32_t size) {
-	uint8_t cmd[2] = {reg, 0x00};
+	uint8_t cmd[2];
+	cmd[0] = reg;
+	cmd[1] = 0x00;
+
 	write(fd, cmd, 2);
 	
 	if (read(fd, dst, size) != (ssize_t)size) {
 		fprintf(stderr, "error read()\n");
-		return I2C_ERR;
+		return 1;
 	
 	}

-	return I2C_OK;
+	return 0;
 }


 int i2c_write(uint8_t reg, uint8_t value) {
-	uint8_t cmd[2] = {reg, value};
+	uint8_t cmd[2];
+	cmd[0] = reg;
+	cmd[1] = value;
 	
 	if (write(fd, cmd, 2) != 2) {
 		fprintf(stderr, "error write()\n");
-		return I2C_ERR;
+		return 1;
 	}

-	return I2C_OK;
+	return 0;
 }

 int i2c_deinit(void) {
@ -67,6 +68,6 @@ int i2c_deinit(void) {
 		close(fd);
 	}

-	return I2C_OK;
+	return 0;
 }

--- a/i2c.h
+++ b/i2c.h
@ -3,9 +3,6 @@

 #include <stdint.h>

-#define I2C_OK  0
-#define I2C_ERR 1
-
 int i2c_init   (void);
 int i2c_read   (uint8_t reg, uint8_t *dst, uint32_t size);
 int i2c_write  (uint8_t reg, uint8_t value);
--- a/registers.h
+++ b/registers.h
@ -1,70 +0,0 @@
-#ifndef REGISTERS_H
-#define REGISTERS_H
-
-/* SPI page number 0 => 0x00 to 0x7F */
-/* SPI page number 1 => 0x80 to 0xFF */
-#define REG_SPI_PAGE(v) ((v > 0x7F) ? 0 : 1)
-#define REG_SPI_PAGE_MAP(v) (v == 0 ? "LOW" : "HIGH")
-
-#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_MEAS_STATUS 0x1D
-
-
-
-#endif
--- a/spi.c
+++ b/spi.c
@ -1,8 +1,4 @@
-/* 
-
-Example SPI use on linux/raspberry pi
-
-*/
+/* Raspberry Pi SPI */

 #include <stdio.h>
 #include <stdint.h>
@ -35,52 +31,48 @@ Example SPI use on linux/raspberry pi

 static int fd;

-//static void print_access(const char *name, uint8_t reg, uint8_t *dst, uint32_t size);
-
 int spi_init(void) {
-
 	uint8_t mode = SPI_MODE;
 	uint8_t bits = SPI_BITS;
 	uint32_t speed = SPI_SPEED;

 	if ((fd = open(SPI_DEVICE, O_RDWR)) < 0) {
 		fprintf(stderr, "spi open(%s)\n", SPI_DEVICE);
-		return SPI_ERR;
+		return 1;
 	}

 	if (ioctl(fd, SPI_IOC_RD_MODE, &mode) == -1) {
 		fprintf(stderr, "SPI_IOC_RD_MODE\n");
-		return SPI_ERR;
+		return 1;
 	}

 	if (ioctl(fd, SPI_IOC_WR_MODE, &mode) == -1) {
 		fprintf(stderr, "SPI_IOC_WR_MODE\n");
-		return SPI_ERR;
+		return 1;
 	}

 	if (ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits) == -1) {
 		fprintf(stderr, "SPI_IOC_WR_BITS_PER_WORD\n");
-		return SPI_ERR;
+		return 1;
 	}

 	if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) == -1) {
 		fprintf(stderr, "SPI_IOC_RD_BITS_PER_WORD\n");
-		return SPI_ERR;
+		return 1;
 	}

 	if (ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) == -1) {
 		fprintf(stderr, "SPI_IOC_WR_MAX_SPEED_HZ\n");
-		return SPI_ERR;
+		return 1;
 	}

 	if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) == -1) {
 		fprintf(stderr, "SPI_IOC_RD_MAX_SPEED_HZ\n");
-		return SPI_ERR;
+		return 1;
 	}


-//	puts("spi_init");
-	return SPI_OK;
+	return 0;
 }

 /* bme680 auto-increments for spi reads */
@ -101,11 +93,10 @@ int spi_read(uint8_t reg, uint8_t *dst, uint32_t size) {

 	if (ioctl(fd, SPI_IOC_MESSAGE(2), tr) < 0) {
 		fprintf(stderr, "spi_read()\n");
-		return SPI_ERR;
+		return 1;
 	}

-//	print_access("spi_read", reg, dst, size);
-	return SPI_OK;
+	return 0;
 }

 /* bme680 does NOT auto-increment for spi writes, so one at a time */
@ -126,32 +117,16 @@ int spi_write(uint8_t reg, uint8_t value) {

 	if (ioctl(fd, SPI_IOC_MESSAGE(2), tr) < 0) {
 		fprintf(stderr, "spi_write()\n");
-		return SPI_ERR;
+		return 1;
 	}

-//	print_access("spi_write", reg, &value, 1);
-	return SPI_OK;
+	return 0;
 }

 int spi_deinit(void) {
-//	puts("spi_deinit");
 	if (fd) {
 		close(fd);
 	}

-	return SPI_OK;
+	return 0;
 }
-
-/*
-static void print_access(const char *name, uint8_t reg, uint8_t *dst, uint32_t size) {
-	printf("%s: %.2X (%d) [", name, reg, size);
-	for(uint32_t i=0; i<size; i++) {
-		printf("%.2X", dst[i]);
-		if (i < (size - 1)) {
-			printf(", ");
-		}
-	}
-	printf("]\n");
-}
-*/
-
--- a/spi.h
+++ b/spi.h
@ -3,9 +3,6 @@

 #include <stdint.h>

-#define SPI_OK  0
-#define SPI_ERR 1
-
 int spi_init   (void);
 int spi_read   (uint8_t reg, uint8_t *dst, uint32_t size);
 int spi_write  (uint8_t reg, uint8_t value);