Temp sens.c
Revision as of 06:48, 22 May 2007 by SpaceMonkey (talk | contribs)
Grab hold of a "Microchip TC74" temperature sensor IC, a TO220 is easy to handle, and hook it up to the bus using the pins as shown in the hardware hack section. Make sure you use a 3.3v part.
#include <stdio.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#define I2C_DEVICE "/dev/i2c/0"
#define I2C_SLAVE 0x0703
// Write to I2c
int i2c_read (int slaveaddr, unsigned char *buffer, int length)
{
int i2c_fd;
int red;
if( (i2c_fd = open( I2C_DEVICE, O_RDWR)) < 0)
{
printf( "Unable to open the i2c port!\n");
return 100;
}
if( ioctl( i2c_fd, I2C_SLAVE, slaveaddr) == -1)
{
close( i2c_fd);
printf( "Unable to setup the i2c port!\n");
return 101;
}
red=read( i2c_fd, buffer, length);
close( i2c_fd);
return 0;
}
// Read From I2c
int i2c_write (int slaveaddr, unsigned char *buffer, int length)
{
int i2c_fd;
if( (i2c_fd = open( I2C_DEVICE, O_RDWR)) < 0)
{
printf( "Unable to open the i2c port!\n");
return 100;
}
if( ioctl( i2c_fd, I2C_SLAVE, slaveaddr) == -1)
{
close( i2c_fd);
printf( "Unable to setup the i2c port!\n");
return 101;
}
write( i2c_fd, buffer, length);
close( i2c_fd);
return 0;
}
//Whats the temperature
void printtemp()
{
char dbuff[2];
//***TEMPERATURE
i2c_read (0x48, dbuff, 1);
printf ("Temperature :- %d degrees C\n", dbuff[0]);
}
int main(void)
{
printtemp();
return 0;
}