2008-12-07

Creating a PCB with gEDA

I always wanted to try out the gEDA tools for producing PCBs and schematics in the Linux environment.
The ongoing mini85 (8085) project is to big for a first try, there are many packages that are not standard in gEDA, many schematic symbols that also do not come standard, there are many ICs in the schematic, these are too many variables to control for a first time.
I needed something smaller, where I could fully test the tools. I decided to use my USBHID Flight simulator control for this project. I would also try out other things like adding a MACH131SP because it is a SMD component, programmable via a ISP connector (also test the software) and test the package outline of a DB9 connector, the power connector and USB B connector.
I want to send the board for fabrication, most of the PCB fabrication houses need a gerber file (none accepts pcb format), but not many details appear in the official tutorial.

The schematic editor has a reasonable sized library, but if a symbol is needed the procedure is quite fast, I used tragesym and the tutorial is here. I redesigned the symbol for the Atmel AVR AT90S2313 (also ATtiny2313), because I prefer to have direct access to the VCC and GND pins and I don't like the crystal oscillator and the reset input in the bottom. Here is the first page of the schematic.


For converting to PCB I downloaded a library from jluciani, it seems very complete... I still have to understand how to use it properly and in conjunction standard libraries. It needs a small modification of the command line of gsch2pcb.
gsch2pcb --use-files --elements-dir ~/footprints SCHEMATIC_NAME


For now I think the footprints provided are suficient, but I'll probably need to draw new footprints for some older PGA microprocessors (when the time comes)...
Another way will be to try the same system with kicad, it also appears to be a good (free) design tool for linux. It has an extra that for now I don't really need which is the 3D view, but who knows latter...

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