UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - PCB design -- on a BBC Micro!

julie_m · 22nd Jan 2021, 10:09 pm

I have very nearly completed a project to write a program for the BBC Micro, for simple printed circuit board design. This is BCP, which is short for Back of Cigarette Packet -- another versatile design tool.

There is no schematic capture, yet. It takes its circuit input in the form of a slightly-modified SPICE deck (basically, you need to add a comment to the end of each line with a * and the name of the PCB footprint to use) and outputs Gerber and drill files for manufacturing. I was originally planning to incorporate an aperture substitution facility to make it work with mechanical photoplotters with just a 24-position aperture wheel; as it is, it relies on a modern extension to the original format, but the various online viewers I have tried seem to be able to read the files it produces with no problems.

The screen gives a zoomable viewport which can be moved around the design, allowing you to place components and route wiring anywhere.

And I have managed to squeeze all this into a BBC Model B. In theory, nothing is stopping you running the whole thing from cassette, but a floppy drive is recommended. If you can muster a Master, or some shadow RAM, you won't have to choose between four colours just so you can see what's on which layer and 320x256 pixels. It should even run on a 6502 co-processor, again allowing the use of MODE 1.

It's still not finished finished yet, but it's definitely at the "usable with care" stage if anyone would like to try it out.

Would anyone be interested in knowing more?

22nd Jan 2021, 10:09 pm	#1
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	PCB design -- on a BBC Micro! I have very nearly completed a project to write a program for the BBC Micro, for simple printed circuit board design. This is BCP, which is short for Back of Cigarette Packet -- another versatile design tool. There is no schematic capture, yet. It takes its circuit input in the form of a slightly-modified SPICE deck (basically, you need to add a comment to the end of each line with a * and the name of the PCB footprint to use) and outputs Gerber and drill files for manufacturing. I was originally planning to incorporate an aperture substitution facility to make it work with mechanical photoplotters with just a 24-position aperture wheel; as it is, it relies on a modern extension to the original format, but the various online viewers I have tried seem to be able to read the files it produces with no problems. The screen gives a zoomable viewport which can be moved around the design, allowing you to place components and route wiring anywhere. And I have managed to squeeze all this into a BBC Model B. In theory, nothing is stopping you running the whole thing from cassette, but a floppy drive is recommended. If you can muster a Master, or some shadow RAM, you won't have to choose between four colours just so you can see what's on which layer and 320x256 pixels. It should even run on a 6502 co-processor, again allowing the use of MODE 1. It's still not finished finished yet, but it's definitely at the "usable with care" stage if anyone would like to try it out. Would anyone be interested in knowing more? __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.