PCB cad software MM?

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.

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

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.)

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.

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

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

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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.

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.

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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,

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.

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

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.

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.