Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

CDF parameter passing problem

Status
Not open for further replies.

AdvaRes

Advanced Member level 4
Joined
Feb 14, 2008
Messages
1,163
Helped
113
Reputation
220
Reaction score
51
Trophy points
1,328
Location
At home
Activity points
7,442
Hi all,
I'm finding difficulty to pass CDF parameters from a lower level cell to higher level cell in a circuit. Its the first time that I try to use CDF parameter in a hierarchical design.
I designed an inverter with wp, wn, lp and ln (Width of PMOS and NMOS + length of PMOS and NMOS) as CDF parameters. A more complex circuit (the top cell) was designed and required 3 instances of this inverter but with different wp, wl, lp and ln values. The top properties can be set by fixing the 12 parameters wp1 to wp3, wl1 to wl3, lp1 to lp3 and ln1 to ln3. I used pPar() function to set all the CDFs paramters of the top cell.

Simulation showed the paramter set for an instance of the top cell are not passed to the inverters that it encompass. Can sombody help ?
 

Have you made the intermediate levels' properties be
passed through like inverter P device w property is
pPar("wp") within the inverter schematic? You have
to add the CDF fields to do this, but also then use
the passed param at the target primitive.

There is also an [@property] syntax that is more of
a literal passdown, no checking / translating (like for
a text to display a property as-passed).
 

Hi dick_freebird,
Thank you for prompt reply.
For the inverter, pPar("wp"), pPar("wn") , pPar("lp") and pPar("ln") were defined. Using the CDF editor the these parameters were assigned some default values. I also added labels for the symbol to display these properties.
I did so for the top cell circuit following the same principle. For example, pPar("wp1") is used in the CDF property of the first inverter of the top cell to define its wp.
The goal at the is end is to be able to set all the CDF parameter of the top cell and these parameter have to be passed to the different inverters forming the top cell that it turn pass these parameters to the transistors. This seems impossible with pPar and iPar functions with which paramters passing failed.
 

So on the individual inverter properties, like (say) ln,
of inverter1, what is that value set to? "ln1"? Or, if it
is passed down from above, [@ln1]? pPar("ln1")?

You might need to sketch this out and make sure there
is no "missing link" in the chain of property passdowns.
 
  • Like
Reactions: AdvaRes

    AdvaRes

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top