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--- cadence_faqs [2020/09/13 02:42]
vsaxena [Virtuoso Layout Editor FAQs]
+++ cadence_faqs [2021/11/03 22:02] (current)
vsaxena
@@ Line 4: / Line 4: @@
 **A.** Detailed answer is posted [[why_do_we_use_cadence_or_why_can_t_we_use_other_tools|here.]]
+----
 **Q.** My schematic and/or layout is locked up and I can't edit it. What should I do?
@@ Line 11: / Line 11: @@
 A detailed answer is posted [[removing_cadence_lock_files|here]]
+----
 **Q.** What should I do when prompted for license checkout when using Cadence tools?
 **A.** Select the 'Always' option. A common rule when using Cadence is 'Never click Never.
+----
 **Q.** What is a **PDK**?
 **A.** PDK stands for Process Development Kit. Every chip fabrication (fab) service provides a kit that facilitates design, simulation and verification of chips designed using their technology. The PDK consists of Spectre and corner models, Calibre/Diva extraction data, DRC rules, programmable cells (PCells) and miscellaneous scripts.
+----
 **Q.** Can I purchase and install Cadence on my personal computer?
 **A.** No, you can only access it through an X-server client such as X2Go.
+----
 ===== Virtuoso Schematic Editor FAQs=====
@@ Line 29: / Line 30: @@
 **A.** This issue arises when you click 'Never' when prompted for license checkout. A common rule when working with Cadence is 'Never click Never'. This option gets saved in a .cdsenv file in your home directory. To fix this issue, delete the .cdsenv file in your home directory (NOT in the local work directory).
+----
+**Q.** How do I Add a library so that it shows up in my Library Manager?
+**A.** In your project directory, open the cds.lib file. Then if you need to add the library /path/.../NewLibrary, then add a new line to the cds.lib
+<code>DEFINE NewLibrary    /path/.../NewLibrary</code>
+Then, in the Library Manager, click View-> Refresh. You should be able to see the NewLibrary added your library.
+----
+**Q.** How do I make a copy of a library or a cell?
+**A.** In the Library Manager, select a library (or cell) and then Right Click and select Copy option. Then you can define the location of the new library (or cell).
+If you are copying library or a hierarchical cell, then its a good idea to update instances of the entire library, so that your schematic uses local copied cells instead of pointing all the time to the original directory.
+{{:wiki:copy_lib.png?600|}}
+--------
 **Q.** How do I convert Cadence Virtuoso Layout to an image file?
-**A.** [[http://www.mbeckler.org/cadence_plot/|Link]].
+**A.** Follow the [[http://www.mbeckler.org/cadence_plot/|Link]].
+----
 ===== Virtuoso Layout Editor FAQs=====
@@ Line 38: / Line 57: @@
 **Q.** How do I get rid of **layout grid errors** when I perform DRC on my layout?
-**A.** Make sure your major and Minor spacings in layout are multiple of the grid lambda. Lets say for 0.5u process the lambda=0.3u, then you change change the minor spacings to 0.9 and major to 4.5. The grid snap spacing can be 0.15.
+**A.** Make sure your major and Minor spacings in layout are multiple of the grid lambda (λ). For 0.18um CMOS process the λ=0.09u. You can access the display options by the keystroke/bindkey “e.” The grid is set to a snap spacing λ/2 (=45nm) in the layout tool. Here, you can set the minor spacing to 2λ (=0.18μm) and major spacing to 10λ (=0.90μm). You should try to size your devices in the integer multiples of λ and place them on the grid to later avoid grid errors.
+----
 **Q.** LVS for my extracted layout doesn't work, and shows error in si.log "Diva cannot fine switch master cell .... for instance from viewlist."

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