下面是獨立按鍵驅動程序，特點是利用TIMER0中斷，CPU在不停的掃描程序，60ms到，執行按鍵驅動，函數在48ms執行一次，60ms再次執行，避免了CPU資源的浪費

bit  ltkey = 0;       //防止按鍵被長按bit  am_led = 0;uchar  unitTemp = 0xff;bit    amkey;bit    remsg = 0;bit    send = 0;bit    delay100 = 0;bit    mtoa = 0;void KeyScn(void)      //按鍵掃描模塊{uchar NowKeyValue;bit   NowAMKeyValue;//檢測按鍵if(pic == 10)      //首次按鍵檢測{amkey = AMKEY;unitTemp = P2;}if(pic == 13)      //12ms后，再次執行檢測{NowKeyValue = P2;NowAMKeyValue = AMKEY;if(NowKeyValue != unitTemp)   //如果兩次檢測到的結果不同，則認為是抖動，不做處理{unitTemp = 0xff;}if((NowAMKeyValue == amkey)  (amkey == 0))   //如果狀態鍵按鍵有效{if(ltkey == 0){           //AM狀態LED位，0為自動，1為手動am_led = !am_led;if(am_led == 0)       //如果是從手動切回自動，切回到CH1{unitTemp = 0xf7;mtoa = 1;        //由手動切到自動后的標志位}AMLED = am_led;       //狀態燈，變化時寫入ltkey = 1;}}else{ltkey = 0;}}}