说明：  51单片机P2口接4*4键盘的行线和列线；红灯亮时进行频率输入；绿灯亮时进行占空比输入；频率值暂定在100到60KHZ之间；输入频率和占空比时要输够六位整数，不够的在前面补0；占空比以百比数（0-100）形式存在。
(51 Singlechip P2 mouth then 4* 4 keyboard line and column line red light when the frequency of input green when the input duty cycle frequency value is tentatively scheduled for between 100 to 60KHZ input frequency and duty than enough to lose six integers, not enough to fill in front of 0 duty cycle than a few hundred (0-100) form.)