Testing temperature sensor

htu21d.c

@@ -0,0 +1,36 @@
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <linux/i2c-dev.h>
+#include <i2c/smbus.h>
+#include <stdio.h>
+
+#include "htu21d.h"
+
+int i2cReset(int fd)
+{
+	if(ioctl(fd, I2C_SLAVE, ADDR) < 0)
+	{
+		perror("Failed to open the I2C bus: reset\n");
+		return -1;
+	}
+	i2c_smbus_write_byte(fd, RESET);
+	return 0;
+}
+
+//get temp
+int getTemp(int fd, double *temp)
+{
+	char buffer[3];
+	__s32 response = i2c_smbus_read_i2c_block_data(fd, TEMP, 3, buffer);
+	if(response < 0) 
+	{
+		perror("failed to read temperature from sensor\n");
+		return -1;
+	}
+	*temp = -46.85 + 175.72 * (buffer[0]*256+ buffer[1])/65536;
+	return 0;
+
+}
+
+//get humidity
+

main.c

@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "htu21d.h"
+double temperature;
+
+int main(int argc, char *argv[])
+{
+	int fd;
+	char path[20];
+	snprintf(path, sizeof(path), "/dev/i2c-%d", 1);
+	fd = open(path, O_RDWR);
+	if(fd < 0)
+	{
+		perror("Unable to access the i2c bus path\n");
+		return -1;
+	}
+	i2cReset(fd);
+	double temperature;
+	int status = getTemp(fd, &temperature);
+	
+	if(status < 0)
+	{
+		perror("Unable to read temperature\n");
+		return -1;
+	}
+	printf("%5.2f °C\n", temperature);
+	return 0;
+}
+
+//int getTemp(int fd, double *temp) 
+//{
+//	double raw = fd;
+//	temperature = 
+//	getTemp(fd, &temp)
+//}
+