/*****************************************************************************
;Institue of Automation, Chinese Academy of Sciences
;www.hyesco.com
;Description:	ADC driver on Linux for AT91RM9200 
;Date:		2006-3-27	
;Author:	BHB
;E_mail:		
*****************************************************************************/

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

typedef struct  _DA_PARA
{
	int     Channel;
	int	Adc_value;
} AT91_DA_PARA; 

static int fd=-1;

int main()
{
	AT91_DA_PARA dapara;
	float value;
	
	
	location:		
		//輸入DA轉換的數(shù)值；
		printf("please input the Value of DAC(-10~10)!\n");
		scanf("%f",&value);
		printf("value is:%f\r\n",value);
		
		//判斷DA轉換數(shù)值的合法性，DA轉換數(shù)值為－10V～10V；
		if((value<-10)||(value>10))
			{
		 	printf("The input value of the DAC is failed!\r\n");
		 	goto location;
			}	
			
	//設定DAC通道號為1，H9200F僅使用該通道;
	dapara.Channel = 1;	

	//將輸入的數(shù)據(jù)轉化為DA數(shù)字量；
	if(value>=0)
		dapara.Adc_value=((int)((value*100)*32767.0/1000)<<16)&0x7fff0000;
  	else
		dapara.Adc_value=((int)((value+10)*32767/10+32768.0)<<16)&0xffff0000;
	
	//打開設備文件；
	if((fd=open("/dev/dac0",O_WRONLY))==-1)
		{
		perror("open DAC error");
		exit(1);
		}
		
	//送出DA轉換值；
	write(fd,&dapara,sizeof(AT91_DA_PARA));	
	close(fd);
	printf("DAC succeesfully!\r\n");
		
	return 0;
}