说明：  这是关于vhdl中时序语句部分的讲解, 以前在网上搜到这个pdf, 对于时序电路部分讲解非常详细, 解决了很多我看国内教学书部分看不明白的问题, 但是其他内容实在难以找到了.
(This is a single chapter. Regarding the explanation of the sequential sentence part in vhdl, I found this pdf on the Internet. The explanation of the sequential circuit part is very detailed. It solves many problems that I can't understand the part of the domestic teaching book, but the other content is really true. It's hard to find.)