sbit key1down=P1^0 ; // 設開關key1連接此端口
sbit key2down=P1^1 ; // 設開關key2連接此端口
void main（）{
P0=0xff; // 輸出低電平LED亮
LED=0xfe;
while（1）{
P0=LED; delay();
if(key1){ LED <<= 1 ; } // 將LED左移壹位;
if(key2){ LED >>= 1 ; LED |=0x80; } // 將LED右移壹位;
if(key1down==0) { key1=1; key2=0;}
if(key2down==0) { key1=0; key2=1;}
}