MSP430F5529 Interrupts, Timer, and 60 second Count

Now lets look at how to use the pins for output.

There are many ports on the MSP430 (varies on version) , for example PORT-1  ( P1.0 to p1.7 ) & 

PORT-2 ( P2.0 to P2.7 ).

#include <msp430.h> 


/**
 * main.c
 */
void main(void)
{
	WDTCTL = WDTPW | WDTHOLD;	// stop watchdog timer

	 P3DIR=0xFF;                    // P3DIR=0x00;
         P6DIR=0xFF;

         P4DIR |=0x00;
         P4REN |=0xFF;
         P4OUT |=0xFF;

}

 P3DIR |=0x00 tells us that the whole of PORT-3 is initialized to take inputs.

P3DIR |=0xFF tells us that the whole of PORT-3 is initialized to give outputs.

P3DIR |=0x01 only the pin P3.0 is initialized to output in PORT-3.

This follows a Hexadecimal Port mapping.

The Major advantage with the higher versions of MSP430 are , they have inbuilt Pull -Up or Down resistors, so no need to connect externally.

P4REN |=0xFF , this indicates that the pins of PORT-4 have their pull up/down resistors enabled.

TO select them between Pull UP or Pull DOWN, the instruction P$OUT |=0xFF is used.

If 0xFF is used they configure as Pull UP resistors and if 0x00 they configure as Pull DOWN. 

Let's Begin!

Initialize the watchdog timer to OFF state using the required password for the watchdog timer

(It helps to keep check of infinite loops , keeping the processor safe).

#include <msp430f5529.h>         // or #include <msp430.h>


/**
 * main.c
 */
int main(void)
{
	WDTCTL = WDTPW | WDTHOLD;	// The HOLD bit is 1
	
	return 0;
}

WDTCTL is the watch dog timer control register. 

One of the Bit is WDTHOLD , this can be accessed through a specific password value WDTPW.

From WDTHOLD one can control ON and OFF of a Watchdog timer.