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boolean cell description format

mbhealy

I'm trying to use Encounter Library Characterizer to characterize a 4-ported register cell. Apparently ELC can't figure out what the logical description of the cell is. I believe I can tell it what the cell does using the db_gsim -bool command, however I don't know what the format is.

Here is an example from the cadence help system:
DL
, REGISTER([IQ],[XIQ])::=(~[XIQ],~(G?D:[IQ]))
, Q::=[IQ]
;
NAND2
, Y::=~(A&B)
;
TBUF
, Y::=(A(at)EN)
;

Other places in the help system refer to this as the synspec boolean format, but I haven't been able to find anything related to this on google.

Can anyone point me to a guide/tutorial on this boolean format? Or possibly give me more extensive examples?

I've tried reading through the code for bl2gate.pl, but it is very confusing and reading the above format into the script results in errors.


Thanks!
-Michael

  • Hi Michael,

    The boolean approach is pretty old and maybe that's why the documentation on it is light.  Please check if the gate file method will work for you.  To get an example of a gate file, use the following command on a flop that was characterized OK by ELC.

    db_open elc
    db_prepare
    db_gate -r example.gate.file
    db_spice

    Once you have modified the gate file to describe the logic of the complicated gate, add the a couple of extra commands to put the gate file into the database and direct ELC to use it.

    db_open elc
    db_prepare
    cp -p cell1.gatefile elc.ipdb/cell1.design/boundary/gate
    db_gsim -f
    db_spice
    db_output -state -p slow -alf elc.alf -ecsm -lib elc.ecsm.lib
    alf2lib -max -power max -alf elc.alf -lib elc.lib
    exit

    Regards, Wilson

     

     

  •  Thanks for the reply Wilson.

     I see now what you are talking about. I noticed that there was a command to input a boolean file and that using the modified gate file required actually copying files into the database. I thought that the version with the command would be the preferred one. Silly me, I assumed that usability would be a consideration ;).

     Anyways, I have been making progress with your suggestion. I've got power models generated, now I just need to figure out why it isn't giving me timing models.

    Thanks again,

    -Michael

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