How to design Watchdog timer that reset the system if Watchdog counter is not cleared at least every 1/4 seconds
I am not really familiar with MSP controller, but the answer should be something like this:   

#include "msp.h"

void main(void)
{
    volatile uint32_t i, j;
    WDT_A-&gt;CTL = WDT_A_CTL_PW &amp; 0xFF00;
    WDT_A-&gt;CTL = WDT_A_CTL_PW | WDT_A_CTL_IS_5;
    P2DIR |= BIT1;
    while (1) // continuous loop
    {
        P2OUT ^=BIT1; // Blink P1.0 LED
        for (j = 8; j &gt; 0; j--)
        {
             WDT_A-&gt;CTL = WDT_A_CTL_PW &amp; 0XFF00;
             for (i = 750000; i &gt; 0; i--);      // Delay with 3Mhz clock, 0,26s.
        }
    }
 }