cs9-3.c

《手把手教你学单片机的C程序设计》及实验程序

#include <REG51.H>		
#define uchar unsigned char	
#define uint unsigned int	
sbit P3_2=P3^2;			
sbit P3_3=P3^3;			
uchar code SEG7[10]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};
//===============================
uchar data a=0,b=0,out;			
//----------------------------------
uchar key_S1(void);		
uchar key_S2(void);		
void delay(uint k);			
//--------------------------------------
void main(void)			
{						
	while(1)				
	{					
	b= key_S1();			
	a= key_S2();			
	if((a==8)&&(b==5))out=1;	
	else out=0;				
	P0= SEG7[a];			
	P2=0xfd;				
	delay(2);				
	P0= SEG7[b];			
	P2=0xfe;				
	delay(2);				
	if(out==1)P0= 0x73;	
	else P0=0x00;			
	P2=0xf7;				
	delay(2);				
	}						
}						
//----------------------------------------
void delay(uint k)				
{						
uint i,j;					
for(i=0;i<k;i++){			
for(j=0;j<121;j++)				
{;}}						
}						
//----------------------------------------
uchar key_S1(void)			
{uchar data x;				
P3=0xff;					
if(!P3_2)x=5;				
else x=0;					
return x;						
}							
//----------------------------------------
uchar key_S2(void)				
{uchar data y;				
P3=0xff;					
if(!P3_3)y=8;				
else y=0;					
return y;					
}