/*------------------------------------------------------------------------
插上短路環J1、J8的2腳和J5的2腳短接。下載程序后，按下S3鍵小燈就亮一下，CP-端拉低。
功能:比較器正端輸入外部電壓+2.5V,負端接到按鍵S3上.當CP+>CP-小燈亮即當按下S3鍵LED亮.
--------------------------------------------------------------------------*/
#include "C8051F330.h"
#include <intrins.h>
void CPT0_ISR (void);

sbit LED=P1^0; 
unsigned int i;
//void PORT_Init(void);
//void Comparator_Init (void);
void  Comparator_Init(void)
{


    int i = 0;
    CPT0CN    = 0x8F;
    for (i = 0; i < 35; i++);  // Wait 10us for initialization
    CPT0CN    &= ~0x30;
    CPT0MX    = 0x61;//P0.2為正P1.5為負
    CPT0MD    = 0x23;

}
//This is the port Init setup:
void PORT_Init(void)
{
 
                                                     
	P1SKIP|= 0x20;                                     // 跳過P1^5引腳 
                                                               
	P1MDOUT|= 0x01; 
  
                                                      // P0.2analog input 
	P0SKIP|= 0x04;                                    //  跳過P0^2引腳 
                                            // enable P1.0 outputs as push pull
    LED=0;
                
	XBR1 = 0x40;                                    // enable crossbar 禁止
 
}

void main( void )
{
	PCA0MD &= ~0x40; // disable watchdog
	PORT_Init();
	Comparator_Init();

	LED=0;
	EA=1;
	EIE1|=0X20;


}


void sleep_ms(unsigned int count)
{
  	unsigned char ii,jj;
  	for(ii=0;ii<count;ii++)
    {
      	for(jj=0;jj<250;jj++)
	  	_nop_();			
    }	
}		 
void CPT0_ISR (void) interrupt 12
{
  	CPT0CN &=~ 0x30;		/*清中斷標志位*/
  
	{for(i=0;i<200;i++);
	
		{	LED=1;			/*有鍵按下*/
		sleep_ms(200);
		sleep_ms(200);
		sleep_ms(200);
		LED=0;
		}
	}
}