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Use de_set_item_parameters on sub-circuits

Question asked by ALBUSMW on Feb 28, 2005
Latest reply on Mar 8, 2005 by mfredrik

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Hi!

I have a hierarchical design and want to edit the parameter of a sub-circuit by using AEL (deeper background: install a callback function for the parameter and then set the value in the sub-circuit to this value).

I tried something like de_edit_item ("MyPart1.SubPart1"), but this seems not to work ...

Any hints? :-/

Best regards,

Martin.

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mfredrik Mar 1, 2005 4:17 AM
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I don't think it is possible to get the instance ID or instance handle from within the parameter callback. I'm not sure you want to do it even if you could.

I guess you want to modify the subcircuit based on a parameter value.

Assume you have a subcircuit, mysub, with a parameter called C with a parameter callback defined. You placed mysub twice in a schematic. You have now got two instances of mysub, X1 and X2. If you change the value of X1.C the callback function is triggered. Assume we could figure out how to modify something withing mysub depending on the C value. This would not be very good since mysub is shared for all instances, e.g. X2 would be affected as well when you change mysub!

There are several possible workarounds for this:
- Add one or more read-only parameters for your part. When C is changed you can change the values of these read-only parameters from within your callback function. These extra parameters can then be used inside your subcircuit to change the behavior with the change of the C value.
- Create your subcircuit in such a way that it adapts to the changes of the C value. For instance you may have a parasitic resistance which is dependent on the value of C. Write an expression for the resistance value. Here's some example ways to do that:
  
  R = 0.15 + C * 1000
  
  R = if (C=10E-12) then 0.1 elseif (C<20E-12) then 0.15 else 0.2 endif
  
  R = pwl(C,10E-12,0.1,20E-12,0.15,30E-12,0.17)
- Define a netlist callback function. This callback is called at netlist time. You could change the way the subcircuit is netlisted depending on the C value. Netlist callbacks are however not trival and I wouldn't try to use that unless you really have to.
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ALBUSMW Mar 3, 2005 1:56 AM
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Hello!

I got a bit confused ...

- Assume a subcircuit "SubS" with 1 resistor in it, call is "SubR". I place this subcircuit as a design in a Design Kit. I then create a new design and place 2 times my subsircuit from this design kit and change the values inside the 2 subcircuits. I can not save this design because there is only one design behind... - What to do?

- I could overcome this if I can change the values inside this circuit because this is only temporary and need not to be saved.
I would need a de_edit_item("SubS1.SubR") which I could access from my custom menu, but this does not work. Is it somehow possible to access the parameters of a subcircuit from the top with AEL (i know the name of the current selected instance and so on ...).

Best regards, and sorry about the somehow strange questions ...

Martin.
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mfredrik Mar 3, 2005 2:56 AM
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I still don't quite understand how this is supposed to work, nor how you would execute it.

Anyway, here's an example that shows how to change a parameter value of a component using AEL.

Set Parameter Value
http://edasupportweb.soco.agilent.com/cgi-bin/show.pl?id=8593

The script assumes that the component is within the current design which doesn't seem to be the case for you. So you would have to modify it a bit.
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ALBUSMW Mar 3, 2005 6:56 AM
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Hello!

Thanks for the example, but this does not really clearify my questions...

The problem:

I have a design (*.dsn in the CIRCUITS\DESIGNS folder) in a design kit. This design has about 15 parameters (created with create_item, inside a *.ael file in the CIRCUITS\AEL folder) and a Voltage Source which has a data file (TIM-File) behind.
I now want to introduce a 16. parameter which indicated the NAME of the data file (at the moment, it is a default name).
It would be accaptable that the file name is set when I press a custom menu entry (e.g. "Update Source Voltages") or that it changes if I just change the parameter.

At the moment I have to push into the component and change the file name. When I have a look at the AEL Command Line, the "push-in" is done via selecting a area and pushing in, but I want to "push in" with AEL, e.g. by just writing "MySource.Source_DC" to modify the Source_DC inside the MySource subnetwork.

It is also accaptable to place only 1 component of that type on the scematic...

Become more clear? :-/

All the other things around work perfect, and the help in this forum also helped me very much, but now I am just at a point where I don't know how to go on ...

Best regards,

Martin.
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mfredrik Mar 3, 2005 7:13 AM
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Yes, it is a bit more clear now

Instead of AEL, have you concidered the following approaches instead:
- In the subcircuit which accesses the TIM file, instead of hardcoding the file name you could specify the filename as a variable instead.
  
  For example:
  
  FileName = TIM_FILE_NAME
  
  You can then define a global VAR equation anywhere in your design:
  
  VAR
  global VAR1
  TIM_FILE_NAME = "myfile.tim"
  
  Changing this global VAR would change which file that was read...
- Or why not add an extra parameter to the subcircuit so that you can pass down the filename from the level above!?
An AEL script wouldn't be too hard to create, although I would try to avoid it if necessary.
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ALBUSMW Mar 3, 2005 7:44 AM
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Hello!

That sounds good, but then we will come to the final problem:

TimedDataWrite has also a file FORMAT to specify and which I also want to set, and this can NOT be done with a normal value
(AEL command line code: de_set_item_parameters(itemInfo0SP, ...,prm("_nTimedDataWrite_fYES"),prm("_nTimedDataWrite_ftim","\"C:\ADS_DATA\FILE.SIG\"")));)...

Must the global variable be specified beside the Design Kit desing (so do I have to place one VAR and my Design Kit Design separatly)?

This solution would be also nice because there are no changes in the subcircuit, and changes in a Design Kit subcurcuit can not be saved (correct?).

Any idea?
And the AEL code would also be interesting...

Thanks again for your very fast reply,

Martin.
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mfredrik Mar 3, 2005 9:10 AM
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I do think that a passed parameter would be much better than using a global variable. I would strongly recommend you to try that over using a global variable!

In either case you need to update the design kit subcircuit. (Adding the filename as a passed parameter vs specifying the filename as the global variable)

A passed parameter:
- allows you to pass in different filenames into the subcircuit from different instances - if you like.
- does not require the end user to define a global variable. Easier to use.
- The value is saved in the top design.
PS! Here's an AEL example that can update the FileName parameter on a TimedDataWrite inside a subcircuit. I strongly discourage you from use it - just wanted to share it for educational purpose..

defun change_filename(comp_path, newfilname)
{
decl pos = index(comp_path,".");
if ( pos > 0 )
{
decl topinstID = leftstr(comp_path,pos);
decl subinstID = rightstr(comp_path,strlen(comp_path) - pos - 1);
decl topinstH = db_find_instance(current_design_name(),
REP_SCHEM, topinstID);
if ( topinstH )
{
decl topinstName = db_get_instance_attribute(topinstH,
INST_DESIGN_NAME);

de_update_parameters(topinstName,
REP_SCHEM,
list(subinstID,"FileName",newfilname));
}
}
}

Usage: change_filename("X1.T1","\"test1.tim\"");

PPS! You do not need to change the Parameter Entry Mode in the TimedDataWrite. That is only used for the Browse button so that the correct file filter (*.tim, *.bintim...) is used when a user clicks on Browse in the UI - not needed to change the FileName value. ADS will figure out the right format based on the extension I think.

-Mats
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ALBUSMW Mar 6, 2005 7:16 AM
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Hello!

That sound really good!

But I now have 2 questions:

1.) How to define a global parameter within AEL (within the scematic it would be VAR ?)?

2.) ADS 2003A does NOT detect the filetype automatically (if I pass .TIM and select .SIG filetype, ADS can not read in the data). What to do now?

Best regards, and a happy new week,

Martin.
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mfredrik Mar 7, 2005 3:14 AM
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To declare a global variable within AEL you just declare it outside a function definition:

decl MYGLOBAL = 10;

defun myfun()
{
de_info(strcat("MYGLOBAL=",MYGLOBAL));
}

The TimedDataWrite is a bit odd. The FileType is derived from the filename entry mode somehow. I can't think of an easy way to change that with AEL from the top of my head. I thought it didn't matter, but apparantly it does.

You can push into a TimedDataWrite component. It's built up with a TimedDataWrite2 and a load resistor. The TimedDataWrite2 has a parameter called FileType which is set when you change the entry mode for the filename on the TimedDataWrite.

A possible workaround is to use the TimedDataWrite2 and the load resistor instead of the TimedDataWrite component. You should be able to set the FileType parameter of the TimedDataWrite2 using AEL.

0 => tim
1 => bintim
2 => ascsig
3 => sig

A word of caution though... The TimedDataWrite2 component is not a supported component! This might not work in a future version of ADS.

-Mats
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ALBUSMW Mar 8, 2005 7:04 AM
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Hello!

That sounds good, but I still have a small problem with the global variable:

I defined the variable with decl... in my User Menu can can also display the variable, but when I use it in my subscematic, the simulator claims that the variable is unknown.

If I do the declaration using the VAR-component, it works.

What am I doing wrong?

Best regards,

Martin.
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mfredrik Mar 8, 2005 7:43 AM
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Declaring a variable in AEL

vs

Defining a variable equation (VAR) in a schematic

is two totally different things!

If you define a global variable in AEL then you can use it within any AEL code. But the simulator is not aware of AEL variables! You need to define the variable in a VAR for the simulator.

I suspect your question is really "How do I insert a VAR equation on a schematic using AEL?". This example shows how to do that.
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Use de_set_item_parameters on sub-circuits

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