Defining units as Giga and Mega

Can anyone tell me how I represent Mega and Giga in the instance's
parameters?

When I define a resistor with a resistance of "1G ohms" it changes
automatically to 512821 ohms. What am I doing wrong?

 

Hi Again,

Cadence documentation :
Virtuoso® Spectre Circuit Simulator User Guide
UNIX> acroread $CDSHOME/doc/sklanguser/sklanguser.pdf
Chaper 5: Parameter Specification and Modeling Features

Well : 1G = 1e+9, 1M=1e+6.
Do mind the case with spectre : 1M=1e+6 but 1m=1e-3 (mili).
NO SPACE between the NUMBER and the Scale factor.

But if your value got changed, means that you've reached the max value
and a callback runs to adjust this value. A good PDK comes with popup
windows that informs designers about any change made by the callback.
You should not see this with the ideal res in the AnalogLib (I didn't
test).

Bye, Riad.

 

Riad KACED wrote, on 04/28/08 22:55:

Actually a good PDK should NOT produce popup windows, as this makes it very hard
to procedurally call the callbacks - in the event you have to do this (and my
feelings on CDF callbacks are well known, but range checking is a reasonable
usage).

That said, most PDKs would normally give a message in the CIW if they
constrained the value of a component.

Having a 1Gohm real resistor on a chip is not terribly likely, so I'm presuming
this is not intended to be a physical component. If so, you're better off using
res from analogLib for such non-physical components, as that's a primitive
resistor in spectre, which doesn't have such limitations.

Regards,

Andrew.

 

Hi Andrew,

Yes, you're right actually, I went through your 'The Dangers of CDF
Callbacks' and I agree It's not a very good practice but :
The CIW tends to be a foreign window for many designers
unfortunately ... If you don't make a pop-up that clearly explains
things, they could waste hours and hours in chasing up while a very
clear message was transcripted into the CIW. That's a pity but it's
sadly happening quite often ...
I'm not adding if I say that some of them are rather needing flashy 3D
animations to get their attention captured ;-)

Emmm, I think I'm getting bad ...

Riad.

 

Riad KACED wrote, on 05/01/08 01:34:

Of course, the same users who don't look at error messages are also those who
have their window manager set so that the window under the cursor automatically
pops to the front, thereby burying any dialog boxes that you might try to put in
front of them...

(and then of course complaining because the tool is waiting for them to press a
button in the dialog box which they've just buried).

That's a bit less of a problem in IC61, but you're still slightly at the mercy
of window manager focus stealing prevention behaviour...

Andrew.

 

Thanks, I understood the message.

 

Thanks... I also understood the message...

 

Dear Sykab,

I do apologize for my comments but you were not the person I was
talking about, please believe me ! I'm feeling guilty ...
I was generally speaking actually, so please don't take that bad !

Thanks for your understanding !

Riad.

 

lol!

That's right, but cadence is something new for me and I'm having some
stupid problems... I spend hours solving problems that I know that
someone can help me easily.
I know that I did stupid questions, but if I didn't ask, I would spend
a week trying to understand that.

Thanks again

 

Hi There !

There are no stupid questions, only the answers are stupid !
That's your right asking whatever you want.
Do mind that all the Cadence experts are EX - Beginners and were
asking very basic questions some day ...
I'm using Cadence for nearly 7 years now but I'm still considering
myslef as a beginner and I'm still asking very very basic questions,
there is no shame to say I don't know !

So please feel free to ask any other questions. We are enjoying
ourselves here just because people like you are coming with problems,
debating, arguing and that's what keeps us very happy because we are
learning everyday ...

Cheers, Riad.

 

Riad KACED wrote, on 05/01/08 22:28:

I entirely concur with Riad here - I was just having a little laugh - but not at
Skyab's expense... hope nobody took offence.

Andrew.

 

Peace and Love for all of us