set_driving_cell的问题？？

chanon

如果我在ＤＣ里用set_driving_cell　－cell_lib  BUFF1X -pin Z [all_inputs]是不是在信号输入时，先输入到BUFF1X再输入到我的设计里，即综合时是不是在输入时插入BUFF1X,谢谢！

chanon

自己顶一下

signallv

不是，是用BUF1X计算transiton timing。

chen.gang.2012

Set_driving_cell is used to tell the TOOL, the driving capability.
TOOL does not insert this BUFF1X in the design, but assumes that the input of design is driven by BUFF1X.
Given driving capability, and the input cap, TOOL can calculate the input transition time.
If transition time is too long, TOOL will  downsize the first cell connected on the input ports to reduce hte cap load.
Note, the transition time impacts the setup / hold timing.