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PCB cad software MM?

I have a pcb program (Sprint layout) and after fooling with it, can't seem to get the grid to coordinate with some of my parts (euro vs us maybe?)

Anyway the grid sizes are 5.08mm, 2.54mm and then lower multiples of those sizes.

Yet, I have some parts that just won't line up (like a Tamura transformer), no matter what I do.

I know there programs that can do both inches and mm (.100 inch etc I guess) but never realized that there is such a problematic difference between a mm and inch grid.

?

Maybe it's just the Tamura but I can see also any .100 headers etc are going to be a problem too.

Reply to
mkr5000
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well I think I'm answering my own question -- I guess 2.54mm is exactly .100 inch but still I'm having trouble with some parts lining up.

this tamura transformer like I say.

maybe there's some sort of macro or something in the program for weird stuff.

Reply to
mkr5000

Is this a routing question? In either case just set the grid to the smallest step and route the part. Then move on with life. The board house will not mind.

Cheers

Reply to
Martin Riddle

inch

Just accept the fact that the pins on some parts are not located on any "nice" grid. (d-subminature PC-mount connector pins are usually on 0.109 inch centers along the connector, and 0.1 inch across it, if I recall correctly.)

--
Peter Bennett, VE7CEI  
peterbb (at) telus.net
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Reply to
Peter Bennett

inch

The originals weren't made for printed circuit boards, though. They were all solder cup pins & sockets at first so it didn't matter.

--
You can't have a sense of humor, if you have no sense.
Reply to
Michael A. Terrell

100 inch

uff.

I *love* Sprint Layout. Small, fast, clean.

Click on the grid symbol, choose "add new grid values", and you can add whatever grid value you want to the list.

I recently made a breadboard pcb that had a 13-pin tube socket on it. I think I used one of the footprint wizards, but I'm not sure...

HTH,

James Arthur

Reply to
dagmargoodboat

com...

It's also easy in Sprint Layout to turn the grid off and place things at whatever X-Y coordinates you want.

-- Cheers, James Arthur

Reply to
dagmargoodboat

inch

I doesn't matter anyway. Why bother to adhere to a grid? When I create footprints I use a spreadsheet entry mode. That way I don't have to mess with grid settings and tedious positioning with the mouse or cursors.

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------
Reply to
Nico Coesel

PCB (gEDA) recently switched its "internal units" to nanometers to accurately accomodate all the grids that are needed for today's parts. We switched to a gridless autorouter long ago.

I usually set my "working grid" according to my layout rules - for 8/8 rules, I use a 4 mil grid, etc.

Reply to
DJ Delorie

inch

Did you make the footprint symbol for this transformer or just grab it out of some library? In any case check the data sheet. You will probably discover that the lead spacing on the part is NOT some multiple of 25,

50 or 100 mils. If that is the case it will never line up with a grid of those dimensions. 
--

Michael Karas
Carousel Design Solutions
http://www.carousel-design.com
Reply to
Michael Karas

Sprint Layout is a great program -- once again I may have posted before going through the pain of "thinking" -- really, I think I just need to tighten up the spacing on my grid now that I know 2.54mm is actually .100 inch !

If I select one of the lower multiples I "may" be alright but haven't tried it yet.

This Tamura may be a odd but I can't imagine anyone with a current part that didn't have a conventional pinout for PCB software.

Reply to
mkr5000

Look at a standard DB25 connector, then place it on a 10mil grid. You will see that routing will be a pain if the grid is too large. I use Eagle, which will snap to end points off grid. Maybe Sprint has a similar feature.

Cheers

Reply to
Martin Riddle

through the pain of "thinking" -- really, I think I just need to tighten up the spacing on my grid now that I know 2.54mm is actually .100 inch !

yet.

didn't have a conventional pinout for PCB software.

Hitachi's 63xx versions of the 68xx micro family come in a 2mm pitch, which can be a PITA at layout time. Also *many* small pcb-mount audio transformers seem to have pin pitches that don't align to any grid I've tried. Both end up being place_and_nudge tasks, and connecting track work may not be all that pretty in terms of regular spacing etc

- similar to D-series connectors that others have cited.

I also ran into a 42-pin pcb transition SIL socket that used a 2.5mm pitch, NOT 2.54 aka 100 thou.

Reply to
who where

through the pain of "thinking" -- really, I think I just need to tighten up the spacing on my grid now that I know 2.54mm is actually .100 inch !

it yet.

didn't have a conventional pinout for PCB software.

I was just looking for a replacement, through hole vertical mount DPDT pushbutton swich and found that 2.5 mm is a common spacing.

--
You can't have a sense of humor, if you have no sense.
Reply to
Michael A. Terrell

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