setup / hold time

先说下参考资料

1.《Virtuoso Liberate MX Reference Manual》

2.《The Art of Hardware Architecture》

For setup time ,the latched data is fully transitioned before the latch is closed.

意：输入完全传输到锁存器的输出，然后锁存器关闭传输。

这样就有以下公式 

Max (Data -> Latched Data_b, Data -> Latched Data) 从输入到 锁存器输出的一段延时

Min (Clk -> Latch_Clk_b, Clk -> Latch_Clk) 时钟到锁存器相关时钟的一段延时

setup time = Max (Data -> Latched Data_b, Data -> Latched Data) - Min (Clk -> Latch_Clk_b, Clk -> Latch_Clk)

For hold time ,the input to the latch does not switch until the latch is closed.

意：锁存器输入数据一直维持不变直到锁存器完全关闭传输

公式

Max (Clk -> Latch_Clk_b,  Clk -> Latch_Clk) 时钟到锁存器相关时钟的一段延时

Min (Data -> Latch_Input，Data -> Latch_Input ) 从输入到锁存器输入的一段延时

hold time = Max (Clk -> Latch_Clk_b,  Clk -> Latch_Clk) - Min (Data -> Latch_Input，Data -> Latch_Input )