OrCAD: How to make a "prototyping" area - Page 1
Forum section: electronics / beginners

author: scrat
author_rank: Frequent Contributor
timestamp: February 25, 2011, 12:52:48 pm
content: Hi all,which could be the best (easier and clean) way to place on my layout a regular grid of plated holes (a bread-board like area) ?I'm placing my first pcb at ITeadStudio, and since it is really economical and you have 10 pieces as default (but I really need only 2), I'd like to add some features for -who knows- some future use.I'm using almost only layer (and not all the area on it), so the BOT will be for some spare footprints and pads for prototyping. I'd like to add some spare plated holes for a prototyping area, placed on a regular (0.1") grid.Thanks,Sandro

author: Time
author_rank: Frequent Contributor
timestamp: February 25, 2011, 05:08:49 pm
content: What do you mean? How to actually go about doing this in the OrCad layout software?

author: scrat
author_rank: Frequent Contributor
timestamp: February 25, 2011, 05:59:51 pm
content: Yes, sorry for the verbose and not well made question. I'll rewrite it...Is there a way in OrCAD to put the components/vias into an array, so to obtain a grid placement?If I want to make a "bread-board" like area, should I use free vias or something other (a component out of the schematic)? I'd like to know the same also about mounting holes: which is the usual way to place them? A component, not reported into the schematic?I managed to learn what I know on CAEs (almost only OrCAD) on my own, so I lack of conventions/tricks. Thanks a lot.

author: Time
author_rank: Frequent Contributor
timestamp: February 25, 2011, 07:21:03 pm
content: For mounting holes I just make a custom part in the schematic and associate a custom foot print with it. If I have 4 mounting holes to ground I label them properly in capture and just tie them to ground or whatever you might want.I've done a prototyping grid before but I added it to the layout after the schematic. Obviously you can't back annotate into the schematic. The only way I know how to do it before hand in the schematic is is make a part with X pins representing X amount of breadboard points and just put no connection on them. Than make a custom footprint and make sure the amount of pins in the footprint matches the amount of pins in the schematic part or it will give you a netlisting error when you import into layout. This is what I would do, thought there might be a better way. Your breadboard area is static and cant be formed to a usable region of your board based on used and unused space if you do this.For just adding it to the layout what I did is create a single pin part with a suitable drill diameter. Make sure to give yourself a sufficient annular ring size since it needs to be more rugid than a solder-once-and-leave-it pad. 30 mils or something is what I might have used. So if you specify a 30 mil drill size and than specify a 90 mil circular pad youll get a 30 mil wide annular ring.Now to get the spacing settings you are after you want to mess with your placement grid. This is the grid that your parts snap to so if you make it match the standard breadboard grid spacing (I think 100 mil, check on that though) youll have no problems with placing the parts spaced properly. Copy and paste becomes your friend for a large breadboard area. Obviously each of these parts will have no connection. Grid settings are an important friend for me.Really once you get the ropes of any layout package you can go about doing things in many different ways. The end result is a few gerbers which say where there is and isnt copper and how you get to that point through the software doesn't matter much. Be sure to print 1:1 to check on footprints and breadboard area spacing/tolerances if you feel insecure. I always do this.edit: oh yes, I see you point out the standard 100 mil grid spacing in your OP

author: scrat
author_rank: Frequent Contributor
timestamp: February 26, 2011, 12:09:53 am
content: Thanks, really a complete answer!Some of your points are the same I'd do, some tricks are very helpful. I think correct setting and frequent change of the snap grid is one of the things I should learn to do.What I was saying about conventions and the usual way to do some things in this kind of job is about correctly and coherently "documenting" my work (so going beyond the simple Gerber I will generate). I'm an EE, but not a professional at schematics and layout, at least for now. For example, one of the things that amazes me is the work flow of an electronic board in a team, where some people work on the schematics, some on the SW, some on the layout. Layout and schematic, in particular, seem to me as a whole thing, while many times they are done by at least two different engineers. How do they annotate and keep track of their considerations about placement, routing of "sensible" signals, thermal issues, and so on. If there's a "standard" way, I want to learn it!It is always a pleasure to hear from experienced people.