该实验算是对前几节所学知识的一个综合应用，实验中用到了MSP430F6638 系统主板
上多个外围设备，其中555 定时器连接成的施密特触发器来对输入波形整形，GPIO 中断用
来计数，按键输入来选择需要的闸门，TIIMER_A 用来给闸门定时，段式液晶显示当前闸门
信息和频率计数结果。(This experiment is a comprehensive application of the knowledge learned in the previous sections, and the MSP430F6638 system motherboard is used in the experiment
A plurality of peripheral devices, wherein 555 timers are connected to the Schmidt trigger to shape the input waveform, and the GPIO interrupt is used
To count, the key input to select the required gate, TIIMER_A used to gate timing, Segment LCD display current gate
Information and frequency counting results.)