ad_test.c

a/d驱动实验与d/a驱动实验 基于清华大学的TEB-44B0实验平台

#include <stdio.h>
#include <errno.h>
#include <sys/select.h>
#include <sys/time.h>

#define DEVICE_FILE_NAME "/dev/ad0809"
#define BUF_N	100

struct timeval my_timeout;

int main(int argc, char ** argv)
{
 	int channel;
	int fd;
	int isTSopen = 0;
 	fd_set ReadFd;
 	unsigned char value[BUF_N];
        int result, i;
	
	if(argc <=1)
	{
	 printf("Useage: ad_test <channel>\n");
	 exit(0);
	}
	
	channel = atoi(argv[1]);
	if((channel < 0) || (channel > 15))
	{
	 printf("channel set error! Set channel 0-7.\n");
	 exit(1);
	}
	
	fd = open(DEVICE_FILE_NAME, 0);
	if(fd < 0)
	{
	 printf("Can't open device file: %s!\n", DEVICE_FILE_NAME);
	 exit(2);
	}
	else {
	 printf("Device %s open -> It works!\n", DEVICE_FILE_NAME);
	 isTSopen = 1;
	}
	
	//result = ioctl(DEVICE_FILE_NAME, fd, 0, channel);
	result = ioctl(fd, 0, channel);
	if(result < 0)
	{
	 printf("channel set error!\n");
	 //return errno;
	}
	
	while(isTSopen)
	{
 	 FD_ZERO(&ReadFd);
	 FD_SET(fd, &ReadFd);
	 	
	 my_timeout.tv_sec = 0;
	 my_timeout.tv_usec = 200000;   //200ms
	 
	 result = select(fd + 1, &ReadFd, NULL, NULL, &my_timeout);
//	 result = select(fd, &ReadFd, NULL, NULL, &my_timeout);
	 if(result > 0)
	 {
	  if(FD_ISSET(fd, &ReadFd)) 
	  {	  
	   result = read(fd, value, sizeof(value));
	   if(result < 0)
	     continue;
	   for(i = 0; i < result; i++)
	   {
	    printf("A/D convert value[%d] = 0x%02x\n", i, value[i]);
	   }
	   break;
	   
	  }
	    
	 }
	 
	}
	return 0;	     
}