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icc route ok后,然后抽spef到pt,这个时候看起来pt的timing比icc要差些的。然后我用pt fix leakage后写出eco file 到icc, 这个时候icc的timing 比起pt反而要差了。
举例一条路径,基本上从clock的source 端到 路径起始端的cp,两边差距很小,不到1p,
然后经过第一个UHVT cell, pt的timing 就表现的比icc好了。我用report_delay_calculation
做比较 , icc的如下:
From pin: apbb_bj/apb1_master/U101/I
To pin: apbb_bj/apb1_master/U101/ZN
Main Library Units: 1ns 1pF 1kOhm
From Pin Operating Voltage, Temperature, Process: 0.81:0.00:1.00
To Pin Operating Voltage, Temperature,Process: 0.81:0.00:1.00
----------------------------------------------------------------
Thresholds Rise_Delay Rise Fall_Delay Fall Rail
i/p o/p Slew i/p o/p Slew Volt
----------------------------------------------------------------
FromPin 50.0 50.0 30.0->70.0 50.0 50.0 70.0->30.0 0.81
ToPin 50.0 50.0 30.0->70.0 50.0 50.0 70.0->30.0 0.81
----------------------------------------------------------------
Library: 'tcbn28hpmbwp35ss0p81v0c_ccs'
Library Units: 1ns 1pF 1kOhm
Library Cell: 'CKND1BWP35HVT'
arc sense: negative_unate
arc type: cell
Information: Using CCS timing info. (TIM-025)
Arnoldi-based Delay Calculation:
RC network on pin 'apbb_bj/apb1_master/U101/ZN' :
------------------------------------------------------
Number of elements = 32 Capacitances + 31 Resistances
Total capacitance = 0.005433 pF
Total capacitance = 0.005433 (in main library unit)
Total resistance = 0.279561 Kohm
Advanced driver-modeling used for rise and fall.
Rise Fall
------------------------------------------------------------------
Input transition time = 0.057684 0.055911 (in main library unit)
Effective capacitance = 0.005522 0.005512 (in pF)
Effective capacitance = 0.005522 0.005512 (in main library unit)
Output transition time = 0.089366 0.093764 (in main library unit)
Cell delay = 0.081317 0.090136 (in main library unit)
pt的如下:
From pin: apbb_bj/apb1_master/U101/I
To pin: apbb_bj/apb1_master/U101/ZN
Main Library Units: 1ns 1pF 1kOhm
Library: 'tcbn28hpmbwp35hvtss0p81v0c_ccs'
Library Units: 1ns 1pF 1kOhm
Library Cell: 'CKND1BWP35HVT'
arc sense: negative_unate
arc type: cell
Calculation Rise Rise Fall Fall Slew Rail
Thresholds: Delay Slew Delay Slew Derate Voltage Temp.
-----------------------------------------------------------------------
from-pin 50 30->70 50 70->30 0.500 0.810 0.0
to-pin 50 30->70 50 70->30 0.500 0.810 0.0
RC network on pin 'apbb_bj/apb1_master/U101/ZN' :
------------------------------------------------------
Number of elements = 44 Capacitances + 49 Resistances
Total capacitance = 0.005018 pF
Total capacitance = 0.005018 (in library unit)
Total resistance = 0.282406 Kohm
Advanced driver-modeling used for rise and fall.
Rise Fall
------------------------------------------------------------------
Input transition time = 0.059973 0.058407 (in library unit)
Effective capacitance = 0.004883 0.004871 (in pF)
Effective capacitance = 0.004883 0.004871 (in library unit)
Output transition time = 0.082545 0.086591 (in library unit)
Cell delay = 0.077849 0.086217 (in library unit)
Annotated max rise delta transition: 0 pin transition: 0.0825446
Annotated max fall delta transition: 0 pin transition: 0.0865911
1
pt的初始transition 比icc的要差,但是别的看起来都比icc快了一些。
请教下大牛们是什么原因?? |
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