FPGAshixu

代码说明：

  FPGA经验总结：时序是设计出来的 我们在做详细设计的时候，对于一些信号的时序肯定会做一些调整的，但是这种时序的调整最多只能波及到本一级模块，而不能影响到整个设计。(FPGA Experience: Timing is designed to do the detailed design of our time, for some signal timing will certainly make some adjustments, but adjust this timing can only spread to up to this level of the module, but not affect the whole design.)