#include <Key.h>

unsigned char Key_Read()
{
    unsigned char temp = 0;
    //第1列
    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;
    //第2列
    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;
    //第3列
    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;
    //第4列
    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;
    return temp;
}