display.c

8255卡驱动,应该不错

#include <_REG51_.H>	
unsigned char code Tab[]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,
                          0x7F,0x6F,0x77,0x7C,0x39,0x5E,0x79,0x71};
sbit	P20	=	P2^0;
sbit	P21	=	P2^1;		
//delay function
void 	Delay(uchar	formal_t)  //cost 6uS while rotate once.cost 11uS while called.[at 12MHz crystalloid]
	{	
		uchar	i;
		i=formal_t;
		while(i--){;}
			
	}

//display function
void	Display(uchar *p)
	{
		uchar	i,p2tmp=0xfe;
		for(i=0;i<8;i++)
			{
				P2=0xFF;
				P0=Tab[*p];
				P2=p2tmp;				
				Delay(5); 	//delay for 11+5*6=41uS.
				p++;
				p2tmp<<=1;
				p2tmp|=0x01;
			}					
	
						
	}

/*
void 	Delay	(uchar	formal_t);
void	Display	(uchar	formal_dat);
*/