msp430看门狗中断实验，当设定时间到达时，指示灯会改变亮灭状态。-Descr iption: Toggle P1.0 using software timed by WDT ISR. Toggle rate is exactly 250ms based on 32kHz ACLK WDT clock source.　In this example the WDT is configured to divide 32768 watch-crystal(2^15) by 2^13 with an ISR triggered @ 4Hz.ACLK = LFXT1 = 32768Hz, MCLK = SMCLK = default DCO