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bus总线上的max_capacitance违例该如何修?

时间:10-02 整理:3721RD 点击:

总线bus三态的单元,相信大家都知道。通过工艺库lib里头的max_capacitance的计算,可以得出大概总线上可以挂的三态单元个数为45个。
可是设计中是有64个寄存器的,明显上挂不了64个。修改工艺库的话,工程量太大。
DC综合时,综合能通过,report_constaints -all时会有max_capaticance违例。从设置set_max_capacitance后再compile_ultra,都一样没办法搞定。
从DC到ICC,再到PT,全部提示max_capacitance违例的问题,请各位大虾支招。
目前自己觉得总线上寄存器的写入和读出,分属与两个不同的周期,应该不会互相干扰到。max_capacitance虽然达不到,波形会恶化,但应该还是能实现功能?
还有在做hold time check时,如何设置set_output_delay -min的值呢?用0的话似乎很难搞定。这个值一般有何经验值呢?
望各位大虾支招了。万分感谢!PT后的违例数据:
RequiredActual
PinCapacitanceCapacitanceSlack
-----------------------------------------------------------------
I6900/U3/N011.83182.5024-0.6706(VIOLATED)
I179/I5347/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I179/TRINV247/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I179/TRINV255/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I180/I7186/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I180/I7218/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I180/I7367/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I217/I5870/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I217/I6711/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I217/TRINV244/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I218/I7262/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I5374/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I5826/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I5871/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I5908/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I5917/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I5930/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I5936/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I5948/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6027/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6036/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6039/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6138/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6193/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6306/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6388/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6422/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6625/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6757/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I6903/Y_tri/N011.83502.5024-0.6674(VIOLATED)
I7269/Y_tri/N011.83502.5024-0.6674(VIOLATED)
TRINV268/Y_tri/N011.83502.5024-0.6674(VIOLATED)
TRINV271/Y_tri/N011.83502.5024-0.6674(VIOLATED)
TRINV274/Y_tri/N011.83502.5024-0.6674(VIOLATED)
TRINV278/Y_tri/N011.83502.5024-0.6674(VIOLATED)
TRINV285/Y_tri/N011.83502.5024-0.6674(VIOLATED)
TRINV287/Y_tri/N011.83502.5024-0.6674(VIOLATED)

还没大虾帮忙啊,自己顶起!

再次顶起!

还是没人回复啊。呼呼。再次顶起

1,不管它。
2,跑跑crosstalk,不差太大就OK。旁边隔离。

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