Circuit Negma

C++, C, VB.NET, PCB, Electronics, Circuit Design

MentorGraphics PADS Logic/PADS Layout :: How to create a part with alphanumeric pins?

Posted by Circuit Negma on February 8, 2010

Created By: Hussein Nosair

    How to create a part with alphanumeric pins?


  1. Create your PCB decal as usual (you might use the Wizard), assign the alphanumerics (you can use the Tools > Assign JDEC Pinning to expedite the process). 
  2. When done go to File > Save Decal. Be sure that the check mark for Save Alphanumerics is checked.
  3. Type in the correct part type name in the box provided and click Save.
  4. Go back to PADS Logic and edit the Part Type.
  5. Create your CAE decal as usual (you might use the Symbol Wizard), add the pins, but do not assign pin numbers. Save the CAE decal.
  6. Edit the Part Type that you created.
  7. Select the Alphanumerics tab and confirm that the alphanumeric assignments match up with the PCB footprint pin numbering (Pin 1 = A1, Pin 2 = A2, etc).
  8. Select the Gates tab and add all the necessary gates and assign the corresponding CAE decals.
  9. Select the first Gate and look at the lower portion of the dialog window.
  10. You should see a series of alphanumeric pin names listed under the Unused Pins column (if not, you should select all the pins on the right hand side for each of the Gates and press the Remove button).
  11. Add each alphanumeric pin in sequence so that the CAE decal will have the pins in the correct order (you may want to edit the CAE decal again to confirm how the sequence numbers appear on your decal. Sequence numbers appear on the pins as #1, #2, etc). You will see the listing of sequence numbers in the Gates tab as well as you add each pin to the gate.
  12. Continue adding pins for each of the gates.
  13. Go to the PCB Decals tab and assign the PCB footprint for this part and then click OK, then save and exit from the Part Editor.

Note:  The sequence number maps to where the alphanumeric pin shows on a CAE decal, but the Alphanumerics tab maps how the alphanumeric pin will relate the the PCB footprint pin assignments.  It is much easier to build the part in reverse as described above because the JDEC pinning in the PADS Layout Decal Editor will speed up the alphanumeric pin assignment process.  Assigning the alphanumerics as you go in the CAE symbol can result in incorrect PCB footprints later down the line.


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