独立按键驱动程序

下面是独立按键驱动程序，特点是利用TIMER0中断，CPU在不停的扫描程序，60ms到，执行按键驱动，函数在48ms执行一次，60ms再次执行，避免了CPU资源的浪费

bit  ltkey = 0;       //防止按键被长按bit  am_led = 0;uchar  unitTemp = 0xff;bit    amkey;bit    remsg = 0;bit    send = 0;bit    delay100 = 0;bit    mtoa = 0;void KeyScn(void)      //按键扫描模块{uchar NowKeyValue;bit   NowAMKeyValue;//检测按键if(pic == 10)      //首次按键检测{amkey = AMKEY;unitTemp = P2;}if(pic == 13)      //12ms后，再次执行检测{NowKeyValue = P2;NowAMKeyValue = AMKEY;if(NowKeyValue != unitTemp)   //如果两次检测到的结果不同，则认为是抖动，不做处理{unitTemp = 0xff;}if((NowAMKeyValue == amkey)  (amkey == 0))   //如果状态键按键有效{if(ltkey == 0){           //AM状态LED位，0为自动，1为手动am_led = !am_led;if(am_led == 0)       //如果是从手动切回自动，切回到CH1{unitTemp = 0xf7;mtoa = 1;        //由手动切到自动后的标志位}AMLED = am_led;       //状态灯，变化时写入ltkey = 1;}}else{ltkey = 0;}}}