Difference between revisions of "Temp sens.c"
From eLinux.org
SpaceMonkey (Talk | contribs) |
SpaceMonkey (Talk | contribs) |
||
| Line 12: | Line 12: | ||
#define I2C_DEVICE "/dev/i2c/0" | #define I2C_DEVICE "/dev/i2c/0" | ||
#define I2C_SLAVE 0x0703 | #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 | //Whats the temperature | ||
Revision as of 13:48, 22 May 2007
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;
}
