bmp085-i2c: add new sensor

bmp085-i2c/Makefile

@@ -0,0 +1,28 @@
+CC = gcc
+CFLAGS = -Wall -O2 -g -I../include
+LFLAGS =
+
+all:	bmp085
+
+../lib/i2c_lib.o:	../lib/i2c_lib.c ../include/i2c_lib.h
+	cd ../lib && make
+
+../lib/graphics_lib.o:	../lib/i2c_lib.c ../include/graphics_lib.h
+	cd ../lib && make
+
+####
+
+bmp085:	bmp085.o ../lib/i2c_lib.o ../lib/graphics_lib.o
+	$(CC) $(LFLASG) -o bmp085 bmp085.o \
+			../lib/i2c_lib.o ../lib/graphics_lib.o -lm
+
+bmp085.o:	bmp085.c ../include/i2c_lib.h ../include/graphics_lib.h
+	$(CC) $(CFLAGS) -c bmp085.c
+
+
+####
+
+clean:	
+	rm -f *~ *.o \
+		bmp085 
+

bmp085-i2c/README

@@ -0,0 +1,3 @@
+This uses a BMP085 on a breakout board from Adafruit.
+
+

bmp085-i2c/bmp085.c

@@ -0,0 +1,360 @@
+/* Code to read the i2c bmp280 Pressure sensor */
+
+/* Based loosely on the adafruit code */
+
+
+#define BMP085_I2CADDR		0x77	// BMP085 I2C address
+
+#define BMP085_ULTRALOWPOWER	0	// Ultra low power mode
+#define BMP085_STANDARD		1	// Standard mode
+#define BMP085_HIGHRES		2       // High-res mode
+#define BMP085_ULTRAHIGHRES	3	// Ultra high-res mode
+#define BMP085_CAL_AC1		0xAA	//	Calibration data (16 bits)
+#define BMP085_CAL_AC2		0xAC	//	Calibration data (16 bits)
+#define BMP085_CAL_AC3		0xAE	//	Calibration data (16 bits)
+#define BMP085_CAL_AC4		0xB0	//	Calibration data (16 bits)
+#define BMP085_CAL_AC5		0xB2	//	Calibration data (16 bits)
+#define BMP085_CAL_AC6		0xB4	//!< R  Calibration data (16 bits)
+#define BMP085_CAL_B1		0xB6	//!< R   Calibration data (16 bits)
+#define BMP085_CAL_B2		0xB8	//!< R   Calibration data (16 bits)
+#define BMP085_CAL_MB		0xBA	//!< R   Calibration data (16 bits)
+#define BMP085_CAL_MC		0xBC	//	Calibration data (16 bits)
+#define BMP085_CAL_MD		0xBE	//	Calibration data (16 bits)
+
+#define BMP085_CONTROL		0xF4	// Control register
+#define BMP085_TEMPDATA		0xF6	// Temperature data register
+#define BMP085_PRESSUREDATA	0xF6	// Pressure data register
+#define BMP085_READTEMPCMD	0x2E	// Read temperature control register value
+#define BMP085_READPRESSURECMD	0x34	// Read pressure control register value
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdint.h>
+
+#include <math.h>
+
+#include <sys/time.h>
+#include <sys/ioctl.h>
+#include <linux/i2c-dev.h>
+
+#include "i2c_lib.h"
+
+static int16_t ac1, ac2, ac3, b1, b2, mb, mc, md;
+static uint16_t ac4, ac5, ac6;
+
+static double c_to_f(double c) {
+
+	return ((9.0/5.0)*c)+32;
+
+}
+
+static int32_t compute_B5(int32_t UT) {
+
+	int32_t X1,X2;
+
+	X1 = (UT - (int32_t)ac6) * ((int32_t)ac5) >> 15;
+	X2 = ((int32_t)mc << 11) / (X1 + (int32_t)md);
+
+	return X1 + X2;
+}
+
+
+static uint16_t read_raw_temperature(int i2c_fd) {
+
+	uint8_t buffer[17];
+	uint16_t temp;
+
+	buffer[0] = BMP085_CONTROL;
+	buffer[1] = BMP085_READTEMPCMD;
+	if ( (write(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error writing temp reg!\n");
+		return -1;
+	}
+
+	/* wait 4.5ms */
+	usleep(5000);
+
+	buffer[0] = BMP085_TEMPDATA;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting AC1!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading AC1!\n");
+		return -1;
+       	}
+	temp = buffer[1] | (buffer[0] << 8);
+
+	return temp;
+}
+
+static uint32_t read_raw_pressure(int i2c_fd,int oversampling) {
+
+	static uint32_t raw;
+	uint8_t buffer[17];
+
+	buffer[0] = BMP085_CONTROL;
+	buffer[1] = BMP085_READPRESSURECMD+(oversampling << 6);
+	if ( (write(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error writing temp reg!\n");
+		return -1;
+	}
+
+	if (oversampling == BMP085_ULTRALOWPOWER) {
+		usleep(5000);
+	} else if (oversampling == BMP085_STANDARD) {
+		usleep(8000);
+	}
+	else if (oversampling == BMP085_HIGHRES) {
+		usleep(14000);
+	}
+	else {
+		usleep(26000);
+	}
+
+	buffer[0] = BMP085_PRESSUREDATA;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting PRESSURE!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 3)) !=3) {
+		fprintf(stderr,"Error reading PRESSURE!\n");
+		return -1;
+       	}
+
+	raw = (buffer[0]<<16) | (buffer[1] << 8) | (buffer[2]<<8);
+	raw >>= (8 - oversampling);
+
+	return raw;
+}
+
+
+int main(int argc, char **argv) {
+
+	signed int result;
+
+	float pressure,temperature;
+
+	int oversampling;
+
+	int32_t ut, up, b3, b5, b6, x1, x2, x3, p;
+	uint32_t b4, b7;
+
+
+	int i2c_fd;
+	unsigned char buffer[16];
+
+	struct timeval start_time; // now_time;
+
+	gettimeofday(&start_time, NULL);
+
+	i2c_fd=init_i2c("/dev/i2c-1");
+	if (i2c_fd < 0) {
+		fprintf(stderr,"Error opening device!\n");
+		return -1;
+	}
+
+
+
+	/* Init BMP085 */
+	if (ioctl(i2c_fd, I2C_SLAVE, BMP085_I2CADDR) < 0) {
+		fprintf(stderr,"Error setting i2c address %x\n",
+			BMP085_I2CADDR);
+		return -1;
+	}
+
+	buffer[0] = 0xD0; // ?
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error writing!\n");
+		return -1;
+	}
+
+        if ( (read(i2c_fd, &buffer, 1)) !=1) {
+       	        fprintf(stderr,"Error reading\n");
+               	return -1;
+       	}
+
+	if (buffer[0]!=0x55) {
+		fprintf(stderr,"Error doing something!\n");
+		return -1;
+	}
+
+
+        /* Get the calibration data */
+	buffer[0] = BMP085_CAL_AC1;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting AC1!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading AC1!\n");
+		return -1;
+       	}
+	ac1 = buffer[1] | (buffer[0] << 8);
+
+	buffer[0] = BMP085_CAL_AC2;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting AC2!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading AC2!\n");
+		return -1;
+       	}
+	ac2 = buffer[1] | (buffer[0] << 8);
+
+	buffer[0] = BMP085_CAL_AC3;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting AC3!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading AC3!\n");
+		return -1;
+       	}
+	ac3 = buffer[1] | (buffer[0] << 8);
+
+	buffer[0] = BMP085_CAL_AC4;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting AC4!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading AC4!\n");
+		return -1;
+       	}
+	ac4 = buffer[1] | (buffer[0] << 8);
+
+	buffer[0] = BMP085_CAL_AC5;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting AC5!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading AC5!\n");
+		return -1;
+       	}
+	ac5 = buffer[1] | (buffer[0] << 8);
+
+	buffer[0] = BMP085_CAL_AC6;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting AC6!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading AC6!\n");
+		return -1;
+       	}
+	ac6 = buffer[1] | (buffer[0] << 8);
+
+	/* cal B */
+
+	buffer[0] = BMP085_CAL_B1;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting B1!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading B1!\n");
+		return -1;
+       	}
+	b1 = buffer[1] | (buffer[0] << 8);
+
+	buffer[0] = BMP085_CAL_B2;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting B2!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading B2!\n");
+		return -1;
+       	}
+	b2 = buffer[1] | (buffer[0] << 8);
+
+
+	/* Cal M */
+
+	buffer[0] = BMP085_CAL_MB;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting MB!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading MB!\n");
+		return -1;
+       	}
+	mb = buffer[1] | (buffer[0] << 8);
+
+	buffer[0] = BMP085_CAL_MC;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting MC!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading MC!\n");
+		return -1;
+       	}
+	mc = buffer[1] | (buffer[0] << 8);
+
+	buffer[0] = BMP085_CAL_MD;
+	if ( (write(i2c_fd, &buffer, 1)) !=1) {
+		fprintf(stderr,"Error setting MD!\n");
+		return -1;
+	}
+	if ( (read(i2c_fd, &buffer, 2)) !=2) {
+		fprintf(stderr,"Error reading M!\n");
+		return -1;
+       	}
+	md = buffer[1] | (buffer[0] << 8);
+
+	while(1) {
+
+		ut=read_raw_temperature(i2c_fd);
+		b5 = compute_B5(ut);
+		temperature = (b5 + 8) >> 4;
+		temperature /= 10;
+
+		ut=read_raw_temperature(i2c_fd);
+
+		printf("Temperature: %.2lfC, %.2lfF\n",
+			temperature,c_to_f(temperature));
+
+		oversampling=BMP085_STANDARD;
+		up=read_raw_pressure(i2c_fd,oversampling);
+
+		/* do pressure calcs */
+		b6 =b5 - 4000;
+		x1 = ((int32_t)b2 * ((b6 * b6) >> 12)) >> 11;
+		x2 = ((int32_t)ac2 * b6) >> 11;
+		x3 = x1 + x2;
+		b3 = ((((int32_t)ac1 * 4 + x3) << oversampling) + 2) / 4;
+
+		x1 = ((int32_t)ac3 * b6) >> 13;
+		x2 = ((int32_t)b1 * ((b6 * b6) >> 12)) >> 16;
+		x3 = ((x1 + x2) + 2) >> 2;
+		b4 = ((uint32_t)ac4 * (uint32_t)(x3 + 32768)) >> 15;
+		b7 = ((uint32_t)up - b3) * (uint32_t)(50000UL >> oversampling);
+
+		if (b7 < 0x80000000) {
+			p = (b7 * 2) / b4;
+		} else {
+			p = (b7 / b4) * 2;
+		}
+		x1 = (p >> 8) * (p >> 8);
+		x1 = (x1 * 3038) >> 16;
+		x2 = (-7357 * p) >> 16;
+
+		p = p + ((x1 + x2 + (int32_t)3791) >> 4);
+
+		pressure = p /1000;
+
+		printf("p=%.2lfkPa\n",pressure);
+
+		sleep(1);
+	}
+
+	return result;
+}
+