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Help on pcells

venuuuuu

  hi all,

     I created pcells(only layouts) and I have schematic. I need to generate layout from schematic through "Genfrom source" option. In some other processes I observed pcells has the views "auCd1" ,"auLvs", "layout","spectre", "symbol".....etc. What is the purpose of theese cells?

    And i have another problem. In schematic Instance had the properties "Gate Length(l), Number of Fingers(nf), Finger Width(fw)". But When I am designing Pcells containg the parameters as above, it is saying that "pcell evaluation failed". 

If my parameters are like GateLength,NumberofFingers ,FingerWidth then pcell oparates normally. I think tool(5141) is not taking the spaces in the parameters.

Parents

  • For the first question, the symbol is a representation of the component that can be placed in a higher level schematic - so it's something that just has the pins of the component and some graphic to represent it. The other views, e.g. auCdl, auLvs, spectre etc are usually copies of the symbol and are used to act as "stopping views" for netlisting. When designs are netlisted by specific netlisters, there will be some kind of switch view list and a stop view list. The switch view list is an ordered list of views to try to expand into, and if the view expanded into is one of the stop view list, it will stop expanding the hierarchy. The default for each of the netlisters is to have a stop list containing the name of the netlister - so generally if a cell has a spectre view, the spectre netlister will stop expanding when it hits that cell. This way you can mark which are primitive components in any netlister.

    You should not have spaces in the parameter names. In fact it would be quite hard to do so (you'd have to escape them in the pcDefinePCell() call). With CDF you can always give your parameters meaningful prompts, whilst keeping the parameter name space-free.

    Regards,

    Andrew.

Reply

  • For the first question, the symbol is a representation of the component that can be placed in a higher level schematic - so it's something that just has the pins of the component and some graphic to represent it. The other views, e.g. auCdl, auLvs, spectre etc are usually copies of the symbol and are used to act as "stopping views" for netlisting. When designs are netlisted by specific netlisters, there will be some kind of switch view list and a stop view list. The switch view list is an ordered list of views to try to expand into, and if the view expanded into is one of the stop view list, it will stop expanding the hierarchy. The default for each of the netlisters is to have a stop list containing the name of the netlister - so generally if a cell has a spectre view, the spectre netlister will stop expanding when it hits that cell. This way you can mark which are primitive components in any netlister.

    You should not have spaces in the parameter names. In fact it would be quite hard to do so (you'd have to escape them in the pcDefinePCell() call). With CDF you can always give your parameters meaningful prompts, whilst keeping the parameter name space-free.

    Regards,

    Andrew.

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