Cannot call pPar for CDF parameter

Hi Farhan,

OK, several things here:

1. Do you really need your symbol to be a pcell - that's relatively unusual (does it change the symbol dependent upon the parameters?)
2. It looks as if the main problem is that your callback is trying to evaluate the value of the CDF parameter (at a guess - you didn't show what that function does). This is doomed to failure - see this article on the Dangers of CDF callbacks
3. pPar in general is fine - just you can't expect the callback to be able to evaluate it - you'd typically have to ensure that it just tolerates it, or write a PDK that doesn't depend on CDF callbacks to derive values. If your callbacks are just checking values (as the name suggests in your case), then they could just suspend doing that check if it looks like an expression of some sort - i.e. isn't a literal value.
4. You should give your callback function a name that distinguishes it from other functions - e.g. a unique prefix.
5. The ?parseAsNumber argument values should be "yes" not "t".

Regards,

Andrew

Thank you Andrew for suggestions and explanation.

 I don't really need a pcell for symbol view (because it doesn't change depending upon parameters). The reason why I created pcell for symbol view is to attach the CDF parameters(e.g. W and L), terminal and net names to it and modify CDF parameters for symbol view while designing circuit.

 This is my callback procedure

procedure(CheckLW(paramId)
prog((val valVar)
if( (val = cdfParseFloatString(paramId->value)) &&
typep(val) != 'flonum then
paramId->value = val
cdfgForm->cdfModified = t
)
if(paramId->value=="" || evalstring(paramId->value) < evalstring(paramId->defValue) then
paramId->value = paramId->defValue
cdfgForm->cdfModified = t
)
);; prog
)

According to my understanding the cdfParseFloatString() function would accept pPar function for CDF parameters. I am using IC6.1.6-64b.500.8 version. Could you please suggest me what should I edit in my callback script to accept the pPar("W") and pPar("L") for symbol view and not for the layout view.

Farhan

Farhan,

cdfParseFloatString doesn't understand pPar(). I'm not sure why you think it would? If you'd read my "Dangers of CDF Callbacks" article that I referenced earlier, it probably would have been clear that you can't have a CDF callback which works this way, because CDF callbacks are evaluated when the properties of an instance are edited; even if you used the information about the particular hierarchical path you've pushed into (using aelSetLineage and aelEnvCompile/aelEnvExecute, for example), it would only be valid for that one occurrence - there could be other hierarchical occurrences which inherit different values - and so your callback results would be wrong.

I still don't see why having a pcell helps - this is just a CDF callback question - and you are trying to do something that CDF callbacks really cannot handle (as described in my article).

Kind Regards,

Andrew.