addrv_test.c

at91rm9200 AD/DA转换驱动 很好的驱动开发范例

#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>

int main(void)
{
        int fd,count;
        int CH;
        short result;     
   if((fd=open("/dev/ad",O_RDWR))==-1)
                {
                perror("open error");
                exit(1);
                }
         
    while(1)
    {
    Loop:
      printf("\n\rPlease Input Channel Number For Testing[0-7]:");
      while ((CH = getchar()) != '\n')
      if(CH>'7')
      {
      printf("\n\rError,The Channel Number Must between 0 ~ 7\n\r");
      goto Loop;
      }
    if((count=write(fd,(char *)&CH,1))!=1)
			{
			perror("write error");
			exit(1);
                        }
    if((count=read(fd,(char*)&result,2))!=2)
                        {
			perror("read error");
			exit(1);
                        }
    
   printf("\n\rThe Input Voltage = %.2fv\n\r",result*10.0/4096.0);
   }    
        close(fd);
        return 0;
   
}