SKILL program or Cadence feature to count number of instances hierarchically including multiples in a schematic

Hi Anna,

I wrote that article - and also this one How can I find the total number of primitive components in my design? which uses the CCSschTree code.

For the simple case, the line in CCSschTree that could be changed to take into account the m-factor is:

(setq count (plus count (or (dbGetq inst numInst) 1))))

this gets the numInst attribute of the instance which is for iterated instances. It would then need to multiply this by the m-factor. The tricky part would be that the property may or may not be called "m" - it depends on the PDK and the primitive device.

Also, from having a quick look at the code, I'm not quite sure the counts are right for when the traversal is done on a config. When I have a moment, I'll spend some time checking that (I wrote this code a long time ago), but I won't be updating it to include m-factor because it is too difficult to make generic - I'll leave that as an exercise for you; if it's not a config, it would be the line I mentioned above that needs changing (I think).

Regards,

Andrew

Hi Andrew,

Yes, I'm using the CCSschTree code that you wrote and I can see the line that you mentioned and tried to edit it.

What I did in the code is to filter all MOS devices which has instance name starting with letter "M", then get the value of the m-factor with "totalM" as property name and then multiply that value with the numInst as you mentioned.

If the device is not a transistor, then it will just do the default counting of instances.

But what I noticed is that let's say I have 2 PMOS devices with the following properties:

PMOS #1 - totalM = 1
PMOS #2 - totalM = 4
The total number of devices I'm getting is just 4, instead of 5.

Can you help me check what I can do with the code I added?

Regarding the config, I do not think I need the config since the code will only be used in schematic view.

Thank you very much!

Regards,

Anna

PS -- I cannot seem to add the code in the comment there's an error. I will try to add it in the next reply.

Here's the code. Attaching it as screenshot. I cannot reply with text.

Anna,

There's a strange quirk with the community forums that it doesn't like code containing the function substring - I tried getting this resolved in the past, but I didn't succeed yet. So that's why it objected to you pasting the code.

From a quick glance at the code (I don't have time to test right now), my guess is that the problem is that when you have the totalM parameter set to 1 on an instance, it's the default value and so the property is not stored on the instance. Consequently, it will be in the then branch of the if because  the instance name begins with "M" but there's no totalM property on the instance; instead it's getting the value from the CDF default (presumably 1), but you completely omitted incrementing the count parameter at all. Maybe something like:

if(uppercase(...) == "M" && dbFindProp(inst "totalM") then
  (setq count (plus count (or (dbGetq inst numInst) 1) * atoi(inst~>totalM)))
else
  (setq count (plus count (or (dbGetq inst numInst) 1)))
)

Andrew

Hi Andrew,

Thank you very much! Your suggestion worked!

Regards,

Anna