butled2.c example added

butled2.c

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+// butled2.c - press button to light LED
+// Two loops , one for each state of the button
+// Launchpad v1.3 board, LED1 active high on P1.0,
+// button B1 active high on P1.3
+// J H Davies, 2006-06-01;
+// Launchpad port: S Reig, 2011-04-23; Code Composer Studio v4.2.3
+// ----------------------------------------------------------------------
+
+#include <msp430g2231.h>	// Specific device
+// Pins for LED and button on port 1
+#define LED1	BIT0
+#define B1		BIT3
+
+void main(void)
+{
+  WDTCTL = WDTPW + WDTHOLD;		// Stop watchdog timer
+  P1DIR |= LED1;				// Set pin with LED1 to output
+
+  for (;;) {					// Loop forever
+	while ((P1IN & B1) == 0) { 	// Loop while button up
+	} 							// doing nothing
+// Actions to be taken when button is pressed
+	P1OUT |= LED1;	 			// Turn LED1 on
+	while ((P1IN & B1) != 0) { 	// Loop while button down
+	} 							// doing nothing
+// Actions to be taken when button is released
+	P1OUT &= ~LED1;				// Turn LED1 off
+	}
+}