Merge pull request energia#64 from energia/issue_64

digitalWrite leaves pin in PWM mode if PWM was previously enabled with analogWrite

Author: robertinant

hardware/msp430/cores/msp430/wiring_digital.c

@@ -79,9 +79,17 @@ void digitalWrite(uint8_t pin, uint8_t val)
 	uint8_t bit = digitalPinToBitMask(pin);
 	uint8_t port = digitalPinToPort(pin);
 	volatile uint16_t *out;
+	volatile uint16_t *sel;
 
 	if (port == NOT_A_PORT) return;
 
+	/*
+	 * Clear bit in PxSEL register to select GPIO function. Other functions like analogWrite(...) 
+	 * will set this bit so need to clear it.
+	 */
+	sel = portSelRegister(port);	/* get the port function select register address */
+	*sel &= ~bit;			/* clear bit in pin function select register */
+
 	out = portOutputRegister(port);
 
 	if (val == LOW) {