p13_1.c

单片机原理与应用实例教程 单片机原理与应用实例教程

#include "REG51.H"

sbit COL1 = P2^2;
sbit COL2 = P2^1;
sbit COL3 = P2^0;
#define LED7 P0

unsigned char Table[] = {
		0x40, 0x4f, 0x24, 0x30, 0x19,
		0x12, 0x02, 0x78, 0x00, 0x10 };
void Scan()
{
	unsigned char i = 0;
	unsigned char D = 0xdf;
	if( COL1 == 0 | COL2 == 0 | COL3 == 0 )
		return;
	for( i = 0; i < 3; i ++ )
	{
		P3 = D;
		if( COL1 == 0 ){
			LED7 = Table[ i * 3 + 1 ];
			break;
		}
		else if( COL2 == 0 ){
			LED7 = Table[ i * 3 + 2 ];
			break;
		}
		else if( COL3 == 0 ){
			LED7 = Table[ i * 3 + 3 ];
			break;
		}
		D = D << 1;
	}	
	P3 = 0xff;
}

void Delay()
{
	unsigned char i;
	for( i = 0; i < 0xff; i ++ )
	{
	}
}

void main()
{
	P0 = 0xff;
	while(1)
	{
		Scan();
		Delay();
	}
}