Difference between revisions of "Temp sens.c"

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<code><pre>
 
<code><pre>
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// Temp Sensor Talkies - Andrew Armstrong 2007
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#include <stdio.h>
 
#include <stdio.h>
 
#include <fcntl.h>
 
#include <fcntl.h>
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#define I2C_DEVICE  "/dev/i2c/0"
 
#define I2C_DEVICE  "/dev/i2c/0"
 
#define I2C_SLAVE  0x0703
 
#define I2C_SLAVE  0x0703
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 +
// Write to I2c
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 +
int i2c_read (int slaveaddr, unsigned char *buffer, int length)
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{
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int i2c_fd;
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int red;
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if( (i2c_fd = open( I2C_DEVICE, O_RDWR)) < 0)
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{
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printf( "Unable to open the i2c port!\n");
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return 100;
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}
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if( ioctl( i2c_fd, I2C_SLAVE, slaveaddr) == -1)
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{
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close( i2c_fd);
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printf( "Unable to setup the i2c port!\n");
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return 101;
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}
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red=read( i2c_fd, buffer, length);
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close( i2c_fd);
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return 0;
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}
  
 
//Whats the temperature
 
//Whats the temperature
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</pre></code>
 
</pre></code>
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[[Category:Software]]

Latest revision as of 12:10, 10 February 2008

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.


// Temp Sensor Talkies - Andrew Armstrong 2007

#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;
}

//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;

}