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Getting rid of the breadboard

A project log for Gigatron TTL microcomputer

Just because! A home computer without microprocessor

marcel-van-kervinckMarcel van Kervinck 09/20/2017 at 22:390 Comments

For reliability it is better to solder everything onto a board. So I took the plunge and learnt how to use KiCad. It seems the circuit can be made on a roughly 9x6 inch board, using very relaxed spacing rules. Even if you ignore the time it takes to draw a proper schematic, making a PCB layout took a lot more time than doing the breadboard version. This surprised me a bit.

Ok, wires are flexible and that speeds things up. Traces are not flexible, and that is why they are more reliable of course. But drawing each segment manually gets harder and harder as the circuit completes. And you don't now if you have to undo major steps until you are almost done. On the other hand, in a breadboard layout you lose a lot of time on debugging wiring mistakes. You win back all that time with the EDA circuit checks, but overall the process is slower.

Perhaps my first PCB shouldn't have been a 144 component, 2 layer monster. But here it is prior to tape-out.

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