可控脉冲发生器的VHDL源代码。设计文件加载到目标器件后，按下按键开关模块的S8按键，在输出观测模块通过示波器可能观测到一个频率约为1KHZ、占空比为50 的矩形波。按下S1键或者S2键，这个矩形波的频率会发生相应的增加或者减少。按下S3键或者S4键，这个矩形波的占空比会相应的增加或减少。-Controllable pulse generator of the VHDL source code. Design documents loaded to the target device and press the button switch module, S8 keys in the output observation module may be observed through the oscilloscope to a frequency of approximately 1KHZ, 50　duty cycle rectangular wave. Press the S1 key or S2 key, the frequency of this rectangular wave occurs a corresponding increase or decrease. Press the S3 or S4 key key, the rectangular wave duty cycle will be a corresponding increase or decrease.