tips & tricks - vlsi from iowa state

7/14/2014 Tips & Tricks - VLSI

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Tips & Tricks

From VLSI

Contents

1 Cadence Tips and Tricks

1.1 Change Waveform Graph windows default settings

1.2 Set the default script/veriogA editor in Cadence to gedit

1.3 Set # of sig figs on schematic annotation

1.4 Disable "What's New" Window

1.5 Save operating point information over a DC sweep

1.6 Locked Files in Cadence

1.7 Automatically Open the Library Manager2 Other Tips and Tricks

2.1 Make Nautilus (file manager) behave like a browser

2.2 Firefox profile lock (error message with "Firefox is currently running...")

Cadence Tips and Tricks

Change Waveform Graph windows default settings

Add some of the following lines to .cdsenv file to change the window size, background/foreground color, font size,line thickness,and etc.

;width

viva.graphFrame width string "900"

;height

viva.graphFrame height string "700"

;background color

viva.rectGraph background string "white"

;foreground color

viva.rectGraph foreground string "black"

;axis font

viva.axis font string "Fixed [Misc],14,-1,5,50,0,0,0,0,0"

;marker font

viva.pointMarker font string "Fixed [Misc],14,-1,5,50,0,0,0,0,0"

viva.horizMarker font string "Fixed [Misc],14,-1,5,50,0,0,0,0,0"

viva.vertMarker font string "Fixed [Misc],14,-1,5,50,0,0,0,0,0"

viva.multiDeltaMarker font string "Fixed [Misc],14,-1,5,50,0,0,0,0,0"

viva.refPointMarker font string "Fixed [Misc],14,-1,5,50,0,0,0,0,0"

;line thickness

viva.trace lineThickness string "thick"



You may also use envSetVal to set the environment. For example, to set the background to white, type thefollowing in the CIW window.

envSetVal(viva.rectGraph background 'string white)

Set the default script/veriogA editor in Cadence to gedit

Option 1: type the following in CIW command line

editor="gedit"

Option 2: add the line to .cdsinit

editor="gedit"

Set # of sig figs on schematic annotation

Sometimes the number of significant figures on schematic annotations (node voltages, for example) is very high andit becomes difficult to read. To fix this, type the following into the icfb window:

envSetVal("auCore.misc" "labelDigits" 'int 5)

Change the number 5 to your desired number of sig figs. To make this change permanent, add the line to your~/.cdsenv file.

Disable "What's New" Window

You may not have noticed, but a simple graphical method has been included in icfb to disable the "What's New"window which pops up every time you start. When the window opens, simply choose Edit->Off at Startup andyou will never bothered by the windows again.

Save operating point information over a DC sweep

You may notice that DC operating point information (gm, gds, etc.) does not get saved over a DC sweep. Oneway to work around this is to replicate the sweep using the parametric sweep tool. In some cases, however, thismay constrain your simulation setup. If you simply want the op information to be saved for every point in a sweep,follow these directions:

Make a new text file (saveop.scs, for example) in a directory to which you have read-write access.Add the following line to the file, replacing N0 with the name of the device whos operating point you wish to

save:

save N0:oppoint

Save the file. Return to your ADE window, navigate to Setup->Model Libraries; now the file you justmade to the list.



Run your simulation and find the saved data in the Results Browser (under the Tools menu in the ADE). You

can also access the data with equations (i.e. getData("M0:vdsat" ?result 'dc)).You can, of course, have multiple lines in the file for multiple devices. For large simulations, consider saving

disk space by modifying the file to save only the parameters of interest (i.e, N0:gm). More information aboutthe save command can be found in the spectre documentation or by running spectre -h save at the

terminal.

Locked Files in Cadence

If you try to open an old file and Cadence says you can't edit the file, it is because this file has become "locked."This usually happens as a result of Cadence crashing while the file was open.

To unlock the file, you need to search for and remove (using the rm command) a file that ends in ".cdslck". You willoften have to look through directories and subdirectories to find this file, but look in directories that have the samename as the cellview in question. For example if you are having trouble opening the schematic in cellview "Inverter"in library "myLib" then you would go to the folder myLib/Inverter/ and look for all files ending in ".cdslck".

As an alternative to manually searching through the directories you can use the command (from the directory whereyou start cadence):

find . -name "*.cdslck"

Before you run this command close all open shcematics and layouts. Then simply remove all files that appear.

To remove all cdslck files, you can use the command rm together with searching(from the directory where you startcadence):

find . -name "*.cdslck" -exec rm -f {} \;

Reference: https://secure.engr.oregonstate.edu/wiki/ams/index.php/Cadence/TipsAndTricks#toc11

Automatically Open the Library Manager

In some Cadence environments, the library manager does not open automatically upone starting Cadence. In orderto change this behavior you can simply add the line:

ddsOpenLibManager()

to your .cdsinit file.

Other Tips and Tricks

Make Nautilus (file manager) behave like a browser

Nautilus is the default file manager on the lab computers. You have likely noticed that, with the default settings, itspawns a new windows each time you open a folder. If you find this annoying, you can change its behavior with the
https://secure.engr.oregonstate.edu/wiki/ams/index.php/Cadence/TipsAndTricks#toc11



following steps:

Open the preferences dialogue (Edit->Preferences)

Click on the behavior tab

Tick the always open in browser windows option

Firefox profile lock (error message with "Firefox is currentlyrunning...")

Frequently, if you do not close firefox properly, it will give an error message next time you try to open it. To fix thisproblem, navigate to ~/.mozilla/firefox and look for a folder with a mix of numbers and letters followed by

"Default User". In this folder, you will find an invisible file called .parentlock; delete this file and the problem

should be fixed.

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This page was last modified on 14 August 2013, at 23:28.
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tips & tricks - vlsi from iowa state

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