#include<reg51.h> #define Motors P2#define Switches P1#define Forward 0x05#define Backward 0x0a#define Left 0x06#define Right 0x09#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; } }}