1. include<reg51.h>
  2. define Motors P2
  3. define Switches P1
  4. define Forward 0x05
  5. define Backward 0x0a
  6. define Left 0x06
  7. define Right 0x09
  8. define stop 0x00void

main() { unsigned char SwitchInput; Switches = 0x0f; //Configure Switches as Input Motors = 0X00; //Configure both Motors as Output. while(1)

{	  
SwitchInput = (0x0f & Switches)//read switch status and mask lower byte.     
switch(SwitchInput)	

{

       case 1: Motors = Forward; break;	 
       case 2: Motors = Backward; break;	  
       case 4: Motors = Left; break;	  
       case 8: Motors = Right; break;	  
       default: Motors =stop;	 
       }   
}

}