This is a brief tutorial about building a Symbol for a Schematic in Cadence IC design tool environment for hierarchical design of schematics.

Transcription

1 This is a brief tutorial about building a Symbol for a Schematic in Cadence IC design tool environment for hierarchical design of schematics. 1. > cd work > cadsetup ams > virtuoso& IMPORTANT: You should be seeing following splash windows. If you have not, that means you did not setup the class technology on the directory that you invoked/run Cadence. Splash screens This is Cadence CIW window 4. Run library manager. (CIW: Tools ->Library Manager ) SKIP IF: If you already build a library before using class technology library, skip steps 5-8, and go to step Build a new library. (Library Manager: File->New->Library ) Build it in {work035} directory. Name it something you will use throughout the semester (i.e. mylib035). <OK> Cadence Tutorials Page 1 of 8 T1.Rev.1.0

2 6. Attach and exiting library. <OK> 7. Choose class technology file TECH_C35B4. <OK> 8. Your new library will be listed on the Library list. Cadence Tutorials Page 2 of 8 T1.Rev.1.0

3 9. Make sure that your library has correct technology attached. (LIBRARY MANAGER: { Right Click} on library name -> Properties ) techlibname = TECH_C35B4 10. Build a new schematic cell view in your library. (LIBRARY MANAGER: File-> >New->Cell View ) Give the cell a name such as inv_x1. <OK> Cadence Tutorials Page 3 of 8 T1.Rev.1..0

4 11. Bring primitives from PRIMLIB and a. Click on Create Instance button on Schematic Editor window (SEW) or (SEW:Create->Instance ) or hit i b. Click on Browse on Add Instance window c. Select nmos4 symbol from PRIMLIB, and place it on SEW d. Follow 11.a-c and place a pmos4 symbol on SEW Cadence Tutorials Page 4 of 8 T1.Rev.1.0

5 12. Add input, output, supply and ground pins to the schematic as shown below. Click on Create Pin on SEW or (SEW:Create->Pin ) or hit p Cadence Tutorials Page 5 of 8 T1.Rev.1.0

6 13. Wire connect the transistors and pins to form digital inverter circuit, as shown and Check and Save your schematic. Check CIW and make sure that no error exists on the schematic that you just completed. If warnings and/or errors exist, fix them before moving forward ( i.e. following) Cadence Tutorials Page 6 of 8 T1.Rev.1..0

7 14. Build a Symbol for your inverter schematic. (SEW: Creat->Cellview->From Cellview ). a. <OK> for next window. b. Select location where the pins located on the new symbol, <OK> c. Reshape the symbol ay you like. For example, change the symbol using standard digital representation of the inverter using shapes on the symbol window. d. Check and Save and make sure that no error or warning on the symbol. Cadence Tutorials Page 7 of 8 T1.Rev.1.0

8 Now you can instantiate you inverter cell symbol on any other schematic (i.e. in a new schematic cell, inv_x1_tb). You can go into your schematic by goingg down in the hierarchy. Select the symbol, and (SEW:Edit->Hierarchy- >Descent Edit ) or hit {Shift+E}. Go back up in the hierarchy (SEW: Edit->Hierarcy->Return) or hit {Ctrl+ E} You can edit or read the cell that is descended. Also you can open on same window tab, or a new tab, or Cadence Tutorials Page 8 of 8 T1.Rev.1..0