SI7050 Temperature Sensor

Description

The Si705x Digital Temperature Sensors offer industry-leading low power

consumption and high accuracy across the entire operating voltage and

temperature range. These monolithic CMOS ICs feature a band-gap

temperature sensor element, an analog-to-digital converter with up to 14-

bit resolution, signal processing, calibration data, and an I2C interface.

The patented use of novel signal processing and analog design enables

the sensors to maintain their accuracy over a wide temperature and

voltage range, while consuming very little current.

The temperature sensors are factory-calibrated and the calibration data is

stored in the on-chip non-volatile memory. This ensures that the sensors

are fully interchangeable, with no recalibration or software changes

required.

Applications

HVAC/R

Thermostats

White goods

Computer equipment

Portable consumer devices

Asset tracking

Cold chain storage

Battery protection

Industrial controls

Medical equipment

Pin Assignments:

Application Circuits:

Application Code :

#include <stdio.h>
	#include <stdlib.h>
	#include <linux/i2c-dev.h>
	#include <sys/ioctl.h>
	#include <fcntl.h>
	void main()
	{
	// Create I2C bus
	int file;
	char *bus = "/dev/i2c-1";
	if ((file = open(bus, O_RDWR)) < 0)
	{
	printf("Failed to open the bus. \n");
	exit(1);
	}
	// Get I2C device, SI7050 I2C address is 0x40(64)
	ioctl(file, I2C_SLAVE, 0x40);
	// Send temperature measurement command, NO HOLD MASTER(0xF3)
	char config[1] = {0xF3};
	write(file, config, 1);
	sleep(1);
	// Read 2 bytes of temperature data
	// temp msb, temp lsb
	char data[2]={0};
	if(read(file, data, 2) != 2)
	{
	printf("Error : Input/Output error \n");
	}
	else
	{
	// Convert the data
	float cTemp = (data[0] * 256 + data[1]);
	cTemp = (((cTemp * 175.72) / 65536) - 46.85);
	float fTemp = cTemp * 1.8 + 32;
	// Output data to screen
	printf("Temperature in Celsius : %.2f\n", cTemp);
	printf("Temperature in Fahrenheit : %.2f\n", fTemp);
	}
	}