I am doing my 1st PCB entirely !
I have confusions here regarding the ref. des. of components and How to show them on PCB.
-When I place the component on my PCB design, the Ref des. comes along with it. but that is in Ref. des. --> Assembly Top (class subclass), that doesn't show anything on PCB I guess when It comes in physical form. Also, I can't see them in 3D model view either in Assembly Top or Silkscreen Top layer when all layers are off.
-Also, when I add the text with ref des. written in it and put it in Manufacturer--> Autosilk_top (class subclass) layer, then it shows in silkscreen layer. but not in 3D model view. it will take me too long to add all ref des manually by text and then add it to the Autosilk_top one by one.
What should I do here ?? any simple way to do this? I just want to show up the designators on the top. !
additionally, please let me know the difference between --> Autosilk_top, Assembly_top and Silkscreen_top in PCB (as well in ORCAD) :) Thanks in advance!
If you do not see the Ref Des on Silkscreen_Top when placing the component in the design the symbol is missing the Silkscreen Ref Des text placeholder. I would recommend updating the symbol with the Silkscreen Ref Des Text instead of manually adding it to the design.
There are two separate layers for Ref Des text, PACKAGE GEOMETRY/ASSEMBLY_TOP and PACKAGE GEOMETRY/SILKSCREEN_TOP. Add the text string on both layers for use in the design.
It may seem that it is a duplicate effort have two separate text string placeholders for Ref Des in the symbol but normally Aseembly and Sillkscreen Ref Des are much different: (Size and Location)
Locating the Ref Des placeholder text in the right spot in the symbol will save clean-up time when placing the component in the design.
Hope this helps, Mike Catrambone
It is different from other cad packages (P*DS). There, you select and delete all of the desig "labels" in the design, select all parts, recreate the labels.
In allegro, you >Place >Update Symbols and select package symbols and check "Reset Symbol text location and size".
I understand how that works now.
Quick Question that has been bugging me for years: does it matter what the placeholder string says? #REF, #REFDES.
The placeholder text can be anything. We normally use REFDES, but I've seen JP*, Q*, almost anything. The placeholder DOES define the text size, rotation, and text origin (L, R, Center). The Reference Designation comes from the schematic netlist anyways. Good day.