本文件是PCA实现PWM测试程序，将跳线器JP9的<1，2>,<3，4>，<5，6>，<7，8>，<9，10>脚短接，分别按下4个按键将对应4种脉宽的PWM输出，可通过观察LED的亮度或通过示波器观察。-This document is the PCA to achieve PWM test program, the jumper JP9 of < 1,2, " "　3,4 " ,"　5,6 " ,"　7,8 " ,"　9,10>　pin shorted, respectively The following four keys will correspond to the width of the PWM 4 output by observing the brightness of the LED or by an oscilloscope.