// 芯片 AD420
// 單片機 ATMEGA16
// AD420驅動程序
// Time: 2009-05-07
#include "iom16v.h"
#include "macros.h"
#define uint unsigned int
#define uchar unsigned char

#define CLEAR PA1
#define LATCH PD3 
#define CLOCK PD4 
#define DATAIN PD5
void delay(uint ms)//延時
{
    uint i,j;
for(i=0;i<ms;i++)
    {
    for(j=0;j<1142;j++);
       }
}
//寫數據到AD420
void data_to_AD420(uint Data)
{
   uchar i;
uint x;
uint data;
    data=Data;
// PORTA = 0x00;
// PORTD = 0x00;
PORTA&=~(1<<CLEAR);
PORTD&=~(1<<LATCH);
PORTD&=~(1<<CLOCK);
PORTD&=~(1<<DATAIN);

for(i=0;i<16;i++)
{
   x=data&0X8000;
   if(x==0)
    PORTD&=~(1<<DATAIN);
   else
      PORTD|=BIT(DATAIN);
   PORTD|=BIT(CLOCK);                //CLOCK信號置高
   data=data<<1;
        delay(1);
   PORTD&=~(1<<CLOCK);              //CLOCK信號置低
        delay(1);
}
PORTD|=BIT(LATCH);                    //將串口寄存器中數據送至DAC
}
/*主函數*/
void main(void)
{
   uint k=0;
   //設定為輸出
DDRA|=BIT(CLEAR);
DDRD|=BIT(LATCH)|BIT(CLOCK)|BIT(DATAIN);

while (1) 
{   
k=k+1000;
   data_to_AD420(k);//電流增加
if(k>65535)
{
   k=0;
}
   } 
}