#include <reg51ac2.h>
#include <stdio.h>
#include <LCD16x2.h>
#include <LCD16x2ln.c>
#define UCHAR unsigned char
#define PUERTO P0

void kbInit(){

	PUERTO=0xf;}

UCHAR kbHit(){

	return(PUERTO ^ 0xf);}

UCHAR keyNumber(){
	UCHAR fila,col;
	fila=PUERTO;
	switch(fila)
	{
	case 0x0e:
		fila=0;
		break;
	case 0x0d:
		fila=1;
		break;
	case 0x0b:
		fila=2;
		break;
	case 0x07:
		fila=3;
		break;
	default:
		fila=0xff;
		break;
	}
	PUERTO=0xf0;
	col=PUERTO;
	PUERTO=0x0f;

	switch(col)
	{
	case 0xe0:
		col=0;
		break;
	case 0xd0:
		col=1;
		break;
	case 0xb0:
		col=2;
		break;
	case 0x70:
		col=3;
		break;
	default:
		col=0xff;
		break;
	 }
	 if((fila==0xff)||(col==0xff))
	 	col=0xff;
	 else
	 	col=(fila<<2)+col;
	 return(col);
	 }

UCHAR kbRead(){
	UCHAR uc;
	UCHAR code kbTable[16]={'1','4','7','*',
				'2','5','8','0',
				'3','6','9','#',
				'A','B','C','D'};
	int i;
	while(kbHit()!=0)
	;
	while(kbHit()==0)
	;
	for(i=0;i<3600;i++)
	;
	uc=keyNumber();

	if(uc!=0xff)
		uc=kbTable[uc];
	return(uc);
}


void main(){
	UCHAR tecla;
	init_lcd();
	kbInit();
	
	for(;;){
		
		tecla=kbRead();
		printf("\nLa tecla es:%c",tecla);}}