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predictive berkely transistor models

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sujittikekar1

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back annotated delay

what is meaning of back annotation? please describe in detail.
Thanks in advance.:D
 

back annotate

While you do timing verification in STA tools before doing actual routing you will estimate the wire delay by wire-load models. But before time closing the entire design (ie., after routing) you will be giving the extracted wire delay models in the format of spef or dspf or some other format. So in the STA tool you are again giving back the annotated rc delays. Hope you have understood.
 

back annotation

Hi all,

The back anotaion is nothing but the applying P&R results to the sta tool.i.e
once u r p&R for the design is over they will give the SPEF file to the STA people so the PT will apply the SPEF to the designa and it will caliculate the exact delays on each net.which is called as back anotation.

regards,
ramesh.s
 

spef annotated

HI back annotation is simulating your design again and again to check for its functionality before Synthesis , after synthesis and after place and routing , After placement & routing the actual delays added to the design and this is simulated and compared with the Presynthesis simulation results . And according to your requirements you are coding the design for optimization.
I hope this clarifies..
 

back annotation meaning

back annotation means attach related delay value on cell or net.
that's all


sujittikekar1 said:
what is meaning of back annotation? please describe in detail.
Thanks in advance.:D
Click to expand...
 

back-annotate

Annotate is to append or attach.So after place and route when you get the exact timing data you'll attach this to netlist (i.e back annotate, back can be inferred from the fact you are going back in the design cycle) using some timing analyzer and probably simulate it for functional verification.

Added after 1 minutes:

You can also give the resultant delay to synthesis tool for further logic minimization.
 

backannotated delay

How to do back-annonation using sdf file?
 

site:www.edaboard.com spef syntax

read the netlist using the following command:

read_verilog -netlist netlist_name.v
read_sdf annotated_delay.sdf
read_sdc constraints.sdc
compile

Added after 3 minutes:

To minimize the logic function using synthesis tool(with rela delay sdf) is called forward annotation and to simulate is called back annotation.
To do this you have to give verilog netlist,verilog library and sdf to the simulation tools it will automatically append it.(I remember Modelsim has a compile window having tabs to enter sdf file and remaining data)..
 

annotate means

From a PCB point of view.

Back Annotation is the process of sending PCB layout changes to its schematic.
 

backannotation sdf syntax

back annotation is putting back delays to STA engine and make lfe worst.
 

modelsim spef

spef is a layout extracted file. It have RC values for all the nets.
The syntax is
*NAME_MAP
< mapping of net name to number is done here>
*PORTS
*D_NET <net number> <cap value>

*CONN
<all connections of the net>

*CAP
<cap values>
*RES
<resistance values>

*END
 

back annotation based optimization flow

And post-sim also annotated the SDF for conform the timing is meet.
 

spef & back annotation

Hi sujittikekar1,

Back annotation can be done at mostly every step in flow, basically Back annotation means converting output of certain step ( synthesis or P&R ) in to analyzable components.
 

meaning of back anotated

back annotation is the process that send computed circuit timing parameters to front-end design after layout design.
 

back annotation what is parasitics

I think back annotated is a way to confirm the layout timing meeting the design target.
In STA and post-sim, the SDF must annotate. And also I want to know the information SPEF file.
 

back-annotation issue

by XRC .spef file is stream out
by PT .spef is read in and the sdf file is created
and the modelsim can read the sdf file in to the .v file
thus complete the back simulate of the design
 

what is back annotate timing

i think back annotate has two usages:
1. Pose AP&R, provide the more actual delay(compared to wire load model) to STA tool to do STA
2. Post synthesis, post placement, post clock tree inserting, post routing, provide timing information to simulation tool to do dynamic simulation
 

back annotation spef

would you please suggest a good book for back-annotation?
Thank you
 

back annotation spef, dspf

annotate delays with parasitic delays
 

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