Prueba de escaneo de claves

#include <STC89C5xRC.H>

unsigned char KeySta[3][4] = {  {1,1,1,1},
																{1,1,1,1},
																{1,1,1,1}
														 };

unsigned char  code LedChar[]={0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x7,0x7f,0x6f,0x3f,0x77,0x7C,0x39,0x5E,0x79,0x71};

void main()
{
	unsigned char backup[3][4] = {  {1,1,1,1},
																	{1,1,1,1},
																	{1,1,1,1}
														   };
	unsigned char i,j;
	TMOD &= 0xF0;		//设置定时器模式
	TMOD |= 0x01;		//设置定时器模式
	TL0 = 0x18;		//设置定时初值,1毫秒@12.000MHz
	TH0 = 0xFC;		//设置定时初值
	TF0 = 0;		//清除TF0标志
	TR0 = 1;		//定时器0开始计时
	EA = 1;
	ET0 = 1;
															 
	 while(1)
	 {
			for(i=0;i<3;i++)
			{
				for(j=0;j<4;j++)
				{
					if(backup[i][j] != KeySta[i][j])
					{
						if(backup[i][j] == 0)
						{
							P3 = LedChar[(i*4+j)];
						}
						backup[i][j] = KeySta[i][j];
					}
				}
			}
	 }
}

void InterruptTimer0() interrupt 1
{	
	static unsigned  char keyout = 0;
	unsigned char i = 0;
	static unsigned char keybuf[3][4] = {  {0xFF,0xFF,0xFF,0xFF},
															    　　{0xFF,0xFF,0xFF,0xFF},
																{0xFF,0xFF,0xFF,0xFF}
														   };
	TL0 = 0x18;		
	TH0 = 0xFC;
	keybuf[keyout][0] = (keybuf[keyout][0]<<1) | P04;
	keybuf[keyout][1] = (keybuf[keyout][1]<<1) | P05;
	keybuf[keyout][2] = (keybuf[keyout][2]<<1) | P06;
	keybuf[keyout][3] = (keybuf[keyout][3]<<1) | P07;
	
	for(i=0;i<4;i++)
	{
		if((keybuf[keyout][i] & 0x0F) == 0x00)
		{
			KeySta[keyout][i] = 0;
		}
		else if((keybuf[keyout][i] & 0x0F) == 0x0F)
		{
			KeySta[keyout][i] = 1;
		}
	}
	
	keyout++;
	if(keyout>=3)
	{
		keyout = 0;
	}
	
	switch(keyout)
	{
		case 0: P03=1;P01=0; break;
		case 1: P01=1;P02=0; break;
		case 2: P02=1;P03=0; break;
		default: break;
	}
}