// to control one switch and one led

include <lpc214x.h>

define SwitchPinNumber 15 // build in switch connected with p0.15

define LedPinNumber 16

/ start the main program / int main() { unsigned int switchStatus;

PINSEL0 = 0x000000; //Configure the PORT1 Pins as GPIO;
PINSEL1 = 0x000000; //Configure the PORT1 Pins as GPIO;
PINSEL2 = 0x000000; //Configure the PORT1 Pins as GPIO;

IODIR0 = (0<<SwitchPinNumber); // LED pin as output and Switch Pin as input 

IODIR1=(1<<LedPinNumber);

while(1) {

 /* Turn On all the leds and wait for one second */ 
   switchStatus = (IOPIN0>>SwitchPinNumber) & 0x01 ;  // Read the switch status- shift right side by 15 bit and perform and operation
   // this will shift 15th bit to right and position in 1st bit location. AND will check status in 1st bit location either 1 or 0.

   if(switchStatus == 1)                 //Turn ON/OFF LEDs depending on switch status
   {  
     IOPIN1 = (1<<LedPinNumber);
   }
   else
   {
     IOPIN1 = (0<<LedPinNumber);
   }      
}

}