CAD Stuff

Most of this page is about 2D circuit boards.

For the 3D stuff go here.

Beware -- almost none of this stuff has been built or debugged! It's just here in case it is of some use to someone.

I use Eagle CAD software with the "Pro" license to develop this stuff, but you should be able to use and view it with either the freeware license or the non-profit license. As of 2/20/2016, the version of Eagle being used is Eagle 6.6. (If you retrieved drawings before then, I recommend you get the newer ones.)

The boards
This is a collection of most of my various schematics and boards. There's no documentation for them, so you pretty much have to know what you're looking at, and it may not be obvious which of the zillion boards and schematics is what you want. The list is automatically generated, so if there's stuff in it that I shouldn't be republishing, let me know.

One thing that is there, is that the "DEC" sub-directory has quite a collection of CAD drawings intended to mimic various original DEC boards.

This is a collection of board outlines and the obsolete components, which will be useful if you are trying to re-create flip-chip modules or design new boards for DEC machines. There are outlines and edge connectors for single, double, quad and even hex-height boards.

You will need to set the "Copper/Dimension" design rule to 15 mils, to eliminate diagnostics about copper too close to the edge in the edge connectors. I use 16 mil signal traces and 32 mil power traces, as in 16mils.dru.

You will also want to set the board routing grid to 25 mils (or other sub-multiple of 100 and 125 mils). Otherwise it will be difficult to route from the edge connector to the components, as the edge connector uses a 1/8" grid, and the components typically use a 1/10" grid. I also set the main grid to 50 mils, and the multiple to "2", which causes the grid to be drawn at 0.1" (100 mils). Then I set the alternate grid to 25 mils, so that I can place things to align with the 125 mil grid when necessary. I can also then use the alternate grid to move traces around as needed. (The schematic grid should just be left at the default of 0.1".)

This is a collection of symbolic representations of various DEC flip-chips. For instance, everything needed to draw the prints and backplane for a TC08 DECTape controller is here. The "m" now stands for "module", so all the various flip chip families are intended to be included ([ABGHKMRSW]xxx). The package is one or more H807 connectors, which you can arrange to form your controller backplane. (I recommend arranging them into standard 2x4 connector blocks, or you'll have an even harder problem sourcing compatible connectors!)

Note: This library has been updated. The content formerly in dec-r has been merged in, and the "m" now stands for "modules", including all the various flip-chip series.

Most of what is needed for the various models of the PDP-8/S is there, as well as a fair bit of stuff for the peripherals. Note also that the Sxxx and Bxxx families are essentially faster (and faster yet) versions of the Rxxx module with the same number, so you can often just over-ride the "value" of the Rxxx version to Sxxx or Bxxx.

Some of the older schematics and boards still use dec-r, though. I intend to fix this, as well as some drawings that use dec-m, but fail to "update" in Eagle.

You will want to set the board grid to .125", to get proper placement of the parts. Even so, you may have to move them to get them on-grid, as Eagle tends to place them with incorrect alignment initially.

This is essentially now a copy of dec-m, and it's use is now deprecated. (It won't be tracking future changes from dec-m, for instance.)

Last updated on 02/25/23 02:21