使用MSP430G2231 LANUCHPAD的PWM输出、低通滤波器和比较器制作一个A/D转换器。

要求：

不得使用MSP430 自带的A/D转换器；

A/D转换结果的变化趋势通过开发板的红灯和绿灯表示，红灯亮表示采集信号减小，绿灯亮表示采集信号增大；A/D转换结果可通过查看变量观察，也可其他方式。

分辨力：0.01V，量程：0~2V（直流信号，电位器分压产生）；-Use MSP430G2231 PWM output low-pass filter and comparator to make a A/D converter. : Do not use the MSP430 comes with A/D converter　trend of the A/D conversion results through the development board of the red and green, and red light signal acquisition to reduce the green light to signal acquisition increases　the A/D conversion results can be observed by looking at variables can also be the other way. Resolution: 0.01V, range: 0 ~ 2V (DC signal, potentiometer partial pressure generated)