MSP430 GPIO Programming Reading an external switch

To read an external switch using MSP430 an external switch is connected to P1.4…We uses polling method here to read the switch

/*button_press.c
ganeshredcobra@gmail.com
GPL
An external button connected to P1.4 is used in this example...
connect P1.4 to vcc through a resistor...
*/
#include 

volatile unsigned int i;//to prevent optimization
void main(void)
{
	WDTCTL=WDTPW+WDTHOLD;
 	P1DIR|=0X01;//set all bits in P1 to input except BIT0
	for(;;)
	{
	  if((P1IN & BIT4)==0)//while pushing S1
		P1OUT=0X00;//LED ON
	  else
		P1OUT=0x01;//LED OFF		 
	}
}

When we pushes the button LED will be ON and when we releases it will be OFF…
Happy Hacking 🙂

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