Merge branch 'master' of https://github.com/wrclark/bme680

.gitignore

@@ -1,2 +1,7 @@
 *.o
-bme680
+bme680
+bme680_i2c
+bme680_spi
+bme680_log*
+plot/*.png
+plot/*.txt

Makefile

@@ -1,17 +1,38 @@
 CC=gcc
-OPT=-O2 -std=c99 -Wall -Wextra -W -pedantic
+CFLAGS = -g -O0 -Wall -Wextra -Wpedantic -Wshadow -Wformat=2 -Wfloat-equal \
-CFLAGS=-I. $(OPT)
+         -Wconversion -Wcast-align -Wpointer-arith -Wstrict-overflow=5 \
-CFILES=$(wildcard ./*.c)
+         -Wwrite-strings -Wcast-qual -Wswitch-default -Wswitch-enum \
-OBJECTS=$(patsubst %.c,%.o, $(CFILES))
+         -Wunreachable-code -Wstrict-prototypes -Wmissing-prototypes \
-BINARY=bme680
+         -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)
+all: spi i2c log
-	$(CC) $^ -o $@
+
+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)

README.md

@@ -14,7 +14,21 @@ Connecting the purple BME680 module board to SPI:
 | SCLK     | "SCL"      | GPIO 11 (Pin 23) |
 | CS       | "CS"       | GPIO 8 (Pin 24)  |
 
-## spi demo
+### build
+```sh
+$ make
+```
+This will create demo programs `bme680_i2c` and `bme680_spi`, and logging programs `bme680_log_i2c` and `bme680_log_spi`. They all expect the pin/devices specified in `spi.c` and `i2c.c`.
+
+The loggers spit out the following every minute:
+```
+2024-08-19T18:20:00+0100 22.2358 101068 65.8092 11054.4 1
+```
+`Date`, `Temperature °C`, `Pressure Pa`, `% RH`, `Measured Gas resistance Ω`, `Heat stability bit`
+
+>Note: disregard measured gas resistance if the heat stability bit is not 1.
+
+## bme680_{i2c,spi} demo output
 ```
 par_t1: 26203
 par_t2: 26519
@@ -53,50 +67,9 @@ gas resistance: 12100.310308 Ohm
 === heat_stab_r: 1
 ```
 
-## i2c demo
-```
-par_t1: 26125
-par_t2: 26370
-par_t3: 3
-par_p1: 36262
-par_p2: -10371
-par_p3: 88
-par_p4: 6713
-par_p5: -103
-par_p6: 30
-par_p7: 31
-par_p8: -251
-par_p9: -3158
-par_p10: 30
-par_h1: 776
-par_h2: 1010
-par_h3: 0
-par_h4: 45
-par_h5: 20
-par_h6: 120
-par_h7: -100
-par_g1: 183
-par_g2: 59281
-par_g3: 18
-range_switching_error: 19
-res_heat_range: 1
-res_heat_val: 39
-float mode
-tfine: 97289.819111
-temp: 19.001918 degC
-press: 100226.479673 Pa
-humidity: 67.022216 % RH
-gas resistance: 14702.868852 Ohm
-== for heater target=300.0 and ambient temp=19.0 (degC)
-=== gas_valid_r: 1
-=== heat_stab_r: 1
-```
-
-Note: Do not trust the gas resistance measurement if `heat_stab_r` is not `1`.
-
 ## Burn-in / logging
 
-See file `example/log.c` 
+See file `cmd/log.c` 
 
 ![Graph of gas resistance measured over time](.gitea/gas.png)
 ![Graph of temperature measured over time](.gitea/temp.png)
@@ -105,64 +78,11 @@ See file `example/log.c`
 
 Compile and run
 ```sh
-stdbuf -o0 ./bme680 2>&1 | tee -a log.txt
+$ make
-```
+$ mkdir data
-
+$ stdbuf -o0 ./bme680_log_i2c 2>&1 | tee -a data/i2c.txt &
-This will give an output similar to this:
+$ stdbuf -o0 ./bme680_log_spi 2>&1 | tee -a data/spi.txt &
-```
+# wait a couple of hours or days ..
-2024-05-14T13:03:02+0100 20.8916 99836.7 68.6594 7180.73 1
+$ cd plot
-2024-05-14T13:04:03+0100 20.8658 99840.3 68.7844 7171.53 1
+$ ./plot.sh
-2024-05-14T13:05:03+0100 20.8979 99838.6 68.7759 7162.35 1
-2024-05-14T13:06:03+0100 20.9208 99843.8 68.6436 7166.93 1
-2024-05-14T13:07:03+0100 20.9303 99845.4 68.747 7144.05 1
-2024-05-14T13:08:03+0100 20.9249 99846 68.7122 7139.49 0
-2024-05-14T13:09:04+0100 20.9036 99845.2 68.7224 7157.76 1
-2024-05-14T13:10:04+0100 20.8737 99850.5 68.575 7144.05 1
-2024-05-14T13:11:04+0100 20.8753 99850.6 68.8879 7139.49 1
-2024-05-14T13:12:04+0100 20.9152 99849.3 68.8602 7134.94 1
-```
-
-If last field is not 1 then the measurement, at least for gas resistance, cannot be trusted.
-```sh
-sed -n '/1$/p' log.txt > test.txt
-```
-
-Then graph with gnuplot
-```
-# gnuplot
-reset
-
-set key autotitle columnhead
-set terminal pngcairo enhanced size 2*1920/3,2*1080/3
-set grid
-set xdata time
-set timefmt "%Y-%m-%dT%H:%M:%S%z"
-
-
-
-# gas res vs time 
-set title "[I_{dac}=100, 100ms, target=300 C] GasRes over time"
-set xlabel "Time"
-set ylabel "Gas Resistance (OHM)"
-set output "gas.png"
-plot 'test.txt' u 1:5 w p pt 3 ps 1 t "BME680"
-
-
-set title "[I_{dac}=100, 100ms, target=300 C] Temperature over time"
-set xlabel "Time"
-set ylabel "Temperature (C)"
-set output "temp.png"
-plot 'test.txt' u 1:2 w p pt 3 ps 1 t "BME680"
-
-set title "[I_{dac}=100, 100ms, target=300 C] Pressure over time"
-set xlabel "Time"
-set ylabel "Pressure (Pa)"
-set output "press.png"
-plot 'test.txt' u 1:3 w p pt 3 ps 1 t "BME680"
-
-set title "[I_{dac}=100, 100ms, target=300 C] Humidity over time"
-set xlabel "Time"
-set ylabel "Humidity (%RH)"
-set output "hum.png"
-plot 'test.txt' u 1:4 w p pt 3 ps 1 t "BME680"
 ```

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;
+	uint8_t meas, hum, filter, ctrl_gas1, ctrl_gas0, i;
-	int i;
+	int err = 0;
-	meas = hum = filter = 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.
@@ -281,6 +279,16 @@ int bme680_read(bme680_t *bme680) {
 /*  These arrays are used to compute a sensor heating value `res_heat' */
 /*  for a specified heating target, specified in degree C.             */
 /***********************************************************************/
+/*
+ * Below functions are out of the datasheet
+ */
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Woverflow"
+#pragma GCC diagnostic ignored "-Wstrict-overflow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wfloat-conversion"
+
 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
@@ -299,7 +307,6 @@ static int const_array1_int[16] = {
 	2147483647
 };
 
-/* long int maybe */
 static int const_array2_int[16] = {
 	4096000000, 2048000000, 1024000000, 512000000, 255744255,
 	127110228, 64000000, 32258064, 16016016, 8000000, 4000000,
@@ -375,7 +382,7 @@ 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);
@@ -444,100 +451,6 @@ static void calc_hum_comp (bme680_t *bme680) {
 	}
 }
 
-/********************************************************************/
-// TODO: read one big contiguous block
-int bme680_calibrate(bme680_t *bme680) {
-	uint8_t buffer[3] = {0, 0 ,0};
-	int err = 0;
-
-	/* temperature */
-	err |= read_dev(bme680, 0xE9, buffer, 2);
-	bme680->cal.par_t1 = (buffer[1] << 8) | buffer[0];
-
-	err |= read_dev(bme680, 0x8A, buffer, 2);
-	bme680->cal.par_t2 = (buffer[1] << 8) | buffer[0];
-
-	err |= read_dev(bme680, 0x8C, buffer, 1);
-	bme680->cal.par_t3 = buffer[0];
-
-
-	/* pressure */
-	err |= read_dev(bme680, 0x8E, buffer, 2);
-	bme680->cal.par_p1 = (buffer[1] << 8) | buffer[0];
-
-	err |= read_dev(bme680, 0x90, buffer, 2);
-	bme680->cal.par_p2 = (buffer[1] << 8) | buffer[0];
-
-	err |= read_dev(bme680, 0x92, buffer, 1);
-	bme680->cal.par_p3 = buffer[0];
-
-	err |= read_dev(bme680, 0x94, buffer, 2);
-	bme680->cal.par_p4 = (buffer[1] << 8) | buffer[0];
-
-	err |= read_dev(bme680, 0x96, buffer, 2);
-	bme680->cal.par_p5 = (buffer[1] << 8) | buffer[0];
-
-	err |= read_dev(bme680, 0x99, buffer, 1);
-	bme680->cal.par_p6 = buffer[0];
-
-	err |= read_dev(bme680, 0x98, buffer, 1);
-	bme680->cal.par_p7 = buffer[0];
-
-	err |= read_dev(bme680, 0x9C, buffer, 1);
-	bme680->cal.par_p8 = (buffer[1] << 8) | buffer[0];
-
-	err |= read_dev(bme680, 0x9E, buffer, 2);
-	bme680->cal.par_p9 = (buffer[1] << 8) | buffer[0];
-
-	err |= read_dev(bme680, 0xA0, buffer, 1);
-	bme680->cal.par_p10 = buffer[0];
-
-
-	/* humidity */
-	err |= read_dev(bme680, 0xE2, buffer, 2);
-	bme680->cal.par_h1 = (buffer[1] << 4) | (buffer[0] & 0xF);
-
-	err |= read_dev(bme680, 0xE1, buffer, 2);
-	bme680->cal.par_h2 = (buffer[0] << 4) | ((buffer[1] >> 4) & 0xF);
-
-	err |= read_dev(bme680, 0xE4, buffer, 1);
-	bme680->cal.par_h3 = buffer[0];
-
-	err |= read_dev(bme680, 0xE5, buffer, 1);
-	bme680->cal.par_h4 = buffer[0];
-
-	err |= read_dev(bme680, 0xE6, buffer, 1);
-	bme680->cal.par_h5 = 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];
-
-
-	/* gas */	
-	err |= read_dev(bme680, 0xED, buffer, 1);
-	bme680->cal.par_g1 = buffer[0];
-
-	err |= read_dev(bme680, 0xEB, buffer, 2);
-	bme680->cal.par_g2 = (buffer[1] << 8) | buffer[0];
-
-	err |= read_dev(bme680, 0xEE, buffer, 1);
-	bme680->cal.par_g3 = buffer[0];
-
-	err |= read_dev(bme680, 0x04, buffer, 1);
-	bme680->cal.range_switching_error = buffer[0];
-
-	err |= read_dev(bme680, 0x02, buffer, 1);
-	bme680->cal.res_heat_range = (buffer[0] >> 4) & 3;
-
-	err |= read_dev(bme680, 0x00, buffer, 1);
-	bme680->cal.res_heat_val = buffer[0];
-
-	return err;
-}
-
 /********************************************************************/
 static void calc_gas_res_1(bme680_t *bme680) {
 	double var1, gas_res;
@@ -568,36 +481,6 @@ 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) {
 	double var1, var2, var3, var4, var5;
@@ -606,7 +489,7 @@ static uint8_t calc_target_1(bme680_t *bme680, double target, double ambient) {
 	var1 = ((double)bme680->cal.par_g1 / 16.0) + 49.0;
 	var2 = (((double)bme680->cal.par_g2 / 32768.0) * 0.0005) + 0.00235;
 	var3 = (double)bme680->cal.par_g3 / 1024.0;
-	var4 = var1 * (1.0 + (var2 * (double)target)); /* */
+	var4 = var1 * (1.0 + (var2 * (double)target));
 	var5 = var4 + (var3 * (double)ambient);
 	res_heat = (uint8_t)(3.4 * ((var5 * (4.0 / (4.0 + (double)bme680->cal.res_heat_range)) *
 			(1.0 / (1.0 + ((double)bme680->cal.res_heat_val * 0.002)))) - 25));
@@ -638,3 +521,98 @@ uint8_t bme680_calc_target(bme680_t *bme680, double target, double ambient) {
 	}
 }
 
+#pragma GCC diagnostic pop
+
+/********************************************************************/
+/* TODO: read one big contiguous block */
+int bme680_calibrate(bme680_t *bme680) {
+	uint8_t buffer[3] = {0, 0 ,0};
+	int err = 0;
+
+	/* temperature */
+	err |= read_dev(bme680, 0xE9, buffer, 2);
+	bme680->cal.par_t1 = (buffer[1] << 8) | buffer[0];
+
+	err |= read_dev(bme680, 0x8A, buffer, 2);
+	bme680->cal.par_t2 = (buffer[1] << 8) | buffer[0];
+
+	err |= read_dev(bme680, 0x8C, buffer, 1);
+	bme680->cal.par_t3 = (int8_t)buffer[0];
+
+
+	/* pressure */
+	err |= read_dev(bme680, 0x8E, buffer, 2);
+	bme680->cal.par_p1 = (buffer[1] << 8) | buffer[0];
+
+	err |= read_dev(bme680, 0x90, buffer, 2);
+	bme680->cal.par_p2 = (buffer[1] << 8) | buffer[0];
+
+	err |= read_dev(bme680, 0x92, buffer, 1);
+	bme680->cal.par_p3 = (int8_t)buffer[0];
+
+	err |= read_dev(bme680, 0x94, buffer, 2);
+	bme680->cal.par_p4 = (buffer[1] << 8) | buffer[0];
+
+	err |= read_dev(bme680, 0x96, buffer, 2);
+	bme680->cal.par_p5 = (buffer[1] << 8) | buffer[0];
+
+	err |= read_dev(bme680, 0x99, buffer, 1);
+	bme680->cal.par_p6 = (int8_t)buffer[0];
+
+	err |= read_dev(bme680, 0x98, buffer, 1);
+	bme680->cal.par_p7 = (int8_t)buffer[0];
+
+	err |= read_dev(bme680, 0x9C, buffer, 1);
+	bme680->cal.par_p8 = (buffer[1] << 8) | buffer[0];
+
+	err |= read_dev(bme680, 0x9E, buffer, 2);
+	bme680->cal.par_p9 = (buffer[1] << 8) | buffer[0];
+
+	err |= read_dev(bme680, 0xA0, buffer, 1);
+	bme680->cal.par_p10 = buffer[0];
+
+
+	/* humidity */
+	err |= read_dev(bme680, 0xE2, buffer, 2);
+	bme680->cal.par_h1 = (buffer[1] << 4) | (buffer[0] & 0xF);
+
+	err |= read_dev(bme680, 0xE1, buffer, 2);
+	bme680->cal.par_h2 = (buffer[0] << 4) | ((buffer[1] >> 4) & 0xF);
+
+	err |= read_dev(bme680, 0xE4, buffer, 1);
+	bme680->cal.par_h3 = (int8_t)buffer[0];
+
+	err |= read_dev(bme680, 0xE5, buffer, 1);
+	bme680->cal.par_h4 = (int8_t)buffer[0];
+
+	err |= read_dev(bme680, 0xE6, buffer, 1);
+	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 = (int8_t)buffer[0];
+
+
+	/* gas */	
+	err |= read_dev(bme680, 0xED, buffer, 1);
+	bme680->cal.par_g1 = buffer[0];
+
+	err |= read_dev(bme680, 0xEB, buffer, 2);
+	bme680->cal.par_g2 = (buffer[1] << 8) | buffer[0];
+
+	err |= read_dev(bme680, 0xEE, buffer, 1);
+	bme680->cal.par_g3 = buffer[0];
+
+	err |= read_dev(bme680, 0x04, buffer, 1);
+	bme680->cal.range_switching_error = buffer[0];
+
+	err |= read_dev(bme680, 0x02, buffer, 1);
+	bme680->cal.res_heat_range = (buffer[0] >> 4) & 3;
+
+	err |= read_dev(bme680, 0x00, buffer, 1);
+	bme680->cal.res_heat_val = (int8_t)buffer[0];
+
+	return err;
+}

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

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);
+}

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

cmd/log.c

@@ -7,11 +7,11 @@
 
 #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;
@@ -20,14 +20,29 @@ int main(void) {
 	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;
-	bme680.dev.sleep  = usleep;
+#endif
-
+    bme680.dev.sleep = usleep;
-	mode = BME680_MODE_FLOAT | BME680_I2C | BME680_ENABLE_GAS;
 
+	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");
@@ -35,7 +50,11 @@ int main(void) {
 	}
 
 START:
-	bme680_reset(&bme680);
+    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");
@@ -90,7 +109,7 @@ START:
 
 	temperature = bme680.fcomp.temp;
 
-	// 60 secs
+    /* 60 secs */
 	usleep(1000*1000*60);
 	goto START;
 

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;	
+#if defined(USE_SPI) && defined(USE_I2C)
-//	bme680.dev.read   = i2c_read;
+    #error "Both USE_SPI and USE_I2C are defined. Please define only one."
-//	bme680.dev.write  = i2c_write;
+#elif !defined(USE_SPI) && !defined(USE_I2C)
-//	bme680.dev.deinit = i2c_deinit;
+    #error "Neither USE_SPI nor USE_I2C is defined. Please define one."
-
+#elif defined(USE_SPI)
-	bme680.dev.init   = spi_init;
+    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;
+	mode = BME680_MODE_FLOAT | BME680_ENABLE_GAS;
-	/*     BME680_MODE_INT   | BME680_I2C; */
+#if defined(USE_SPI)
+    mode |= BME680_SPI;
+#elif defined(USE_I2C)
+	mode |= BME680_I2C;
+#endif
+
 
 
 	/* 3. initialise dev func's, and check device id */

i2c.c

@@ -1,8 +1,4 @@
-/* 
+/* Raspberry Pi i2c */
-
-Example I2C use on linux/raspberry pi
-
-*/
 
 #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;
 }
 

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);

plot/gnuplot.gpt

@@ -0,0 +1,38 @@
+# gnuplot
+reset
+
+set key autotitle columnhead top left spacing 2
+set terminal pngcairo enhanced size 2*1920/3,2*1080/3
+set grid linewidth 2
+set xdata time
+set timefmt "%Y-%m-%dT%H:%M:%S%z"
+set xtics format "%d/%m\n%H:%M"
+
+# gas res vs time 
+set title "[I_{dac}=100, 100ms, target=300 C] GasRes over time"
+set xlabel "Time"
+set ylabel "Gas Resistance (OHM)"
+set output "gas.png"
+plot 'i2c.txt' u 1:5 w p pt 3 ps 1 t "bme680-i2c", \
+     'spi.txt' u 1:5 w p pt 3 ps 1 t "bme680-spi"
+
+set title "Temperature over time"
+set xlabel "Time"
+set ylabel "Temperature (C)"
+set output "temp.png"
+plot '../data/i2c.txt' u 1:2 w p pt 3 ps 1 t "bme680-i2c", \
+     '../data/spi.txt' u 1:2 w p pt 3 ps 1 t "bme680-spi"
+
+set title "Pressure over time"
+set xlabel "Time"
+set ylabel "Pressure (Pa)"
+set output "press.png"
+plot '../data/i2c.txt' u 1:3 w p pt 3 ps 1 t "bme680-i2c", \
+     '../data/spi.txt' u 1:3 w p pt 3 ps 1 t "bme680-spi"
+
+set title "Humidity over time"
+set xlabel "Time"
+set ylabel "Humidity (%RH)"
+set output "hum.png"
+plot '../data/i2c.txt' u 1:4 w p pt 3 ps 1 t "bme680-i2c", \
+     '../data/spi.txt' u 1:4 w p pt 3 ps 1 t "bme680-spi"

plot/plot.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env sh
+
+sed -n '/1$/p' ../data/spi.txt > spi.txt
+sed -n '/1$/p' ../data/i2c.txt > i2c.txt
+gnuplot gnuplot.gpt

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

spi.c

@@ -1,8 +1,4 @@
-/* 
+/* Raspberry Pi SPI */
-
-Example SPI use on linux/raspberry pi
-
-*/
 
 #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 0;
-	return SPI_OK;
 }
 
 /* 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 0;
-	return SPI_OK;
 }
 
 /* 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 0;
-	return SPI_OK;
 }
 
 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");
-}
-*/
-

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);