#include <Key.h>

unsigned char Key_Read()
{
	unsigned char temp = 0;
	ET0 = 0;
	
	P44 = 0;P42 = 1;P35 = 1;P34 = 1;
	if(P33 == 0) temp = 4;
	if(P32 == 0) temp = 5;
	if(P31 == 0) temp = 6;
	if(P30 == 0) temp = 7;
	
	P44 = 1;P42 = 0;P35 = 1;P34 = 1;
	if(P33 == 0) temp = 8;
	if(P32 == 0) temp = 9;
	if(P31 == 0) temp = 10;
	if(P30 == 0) temp = 11;
	
	P44 = 1;P42 = 1;P35 = 0;P34 = 1;
	if(P33 == 0) temp = 12;
	if(P32 == 0) temp = 13;
	if(P31 == 0) temp = 14;
	if(P30 == 0) temp = 15;
	
	P44 = 1;P42 = 1;P35 = 1;P34 = 0;
	if(P33 == 0) temp = 16;
	if(P32 == 0) temp = 17;
	if(P31 == 0) temp = 18;
	if(P30 == 0) temp = 19;
	
	ET0 = 1;P3 = 0xff;
	return temp;
}