[参考译文] TCA9543A：检查对要使用该器件的软件的一般理解

// Basic & generic includes
	
	#include <stdio.h>
	#include <unistd.h>
	#include <string.h>
	#include <stdlib.h>
	#include <fcntl.h>
	
	// includes for time
	#include <time.h>
	#include <sys/time.h>

	// includes for I2C
	
	#include <linux/i2c-dev.h>
	#include <sys/ioctl.h>

	int main()
	{
	    
		  int fd2;
		  int fd1;
		  
		  int args;
		  int x;
		  
		  char buf[3];
	      // clear buffers
			
		  buf[0] = 0x00;
		  buf[1] = 0x00;
		  int result;
		
	// Configure BeagleBone
	
		system("config-pin P9_19 i2c");  // reserved for I2C bus, SDA /dev/i2c-2
    	system("config-pin P9_20 i2c");  // reserved for I2C bus, SCL /dev/i2c-2
		system("config-pin P9_26 i2c");  // reserved for I2C bus, SDA /dev/i2c-1
	    system("config-pin P9_24 i2c");  // reserved for I2C bus, SCL /dev/i2c-1
	
	    usleep(200000); 
	  
	
		if ((fd2 = open("/dev/i2c-2", O_RDWR)) < 0)
		
			{
		    	printf("Failed to open I2C bus 2.");
		    	exit(1);
			}
			
		if (ioctl(fd2, I2C_SLAVE, 0x70) < 0) 
			{
		    	printf("Failed to acquire bus 2 access and/or talk to slave.\n");
		    	exit(1);
			}
		// Repeat reading every second until CTRL-Break to stop or bus / device unreachable
		buf[0]  =0x01;
		buf[1]  =0x01;
		
		result = write(fd2,buf,1);
		
		if (result != 1)
		{
			printf("Unable to write to device on channel.\n");
			exit(-9);
		}
		
		printf("Result of writing to set channel was %d\n",result);
		
		if (ioctl(fd1, I2C_SLAVE, 0x28) < 0) 
			{
		    	printf("Failed to acquire bus 2, mux channel 0 access and/or talk to slave.\n");
		    	exit(2);
			}
		
		while(1) 
			{
				
	        // Drive a reading to start
			
			
			result = read(fd1,buf,1);
			
			if (result !=1) //Assume this will return 0 on success
			{
				printf("Read_MR command on bus failed. Result=%d\n",result);
				exit(1);
			}
			
			// wait
			
			usleep(500000);
			
			if (read(fd1,buf, 2) !=2)
			{
				printf("Read_F2 command on bus failed.\n");
				exit(1);
			}
			else
			{
				printf("Values read from bus are:%2x %2x\n",buf[0]&0x3F,buf[1]);
				
			}
			
			
			}
}