Category Archives: DottyMatrix

Getting to grips with the parallel interface

The Centronics interface seemed such an intrinsic part of a computer’s architecture that, to those of us whose computing coming-of-age was in the 1970s or 1980s, it seemed unimaginable that it would all but disappear. Who knew that serial interfaces would one day reign supreme? There’s something still very satisfying about hooking up a parallel connection, with fat cables and… Read more »

First PCB and more mistakes

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Okay, so I’ve already fessed up to some errors I made with my first-ever PCB. Now I’ve discovered another, and it’s a doozy. It’s also a valuable lesson. I’m waiting for a few bits of kit in order to do surface mount soldering. I’ll be writing more about this when it’s all installed (but as a teaser, it’s a hot… Read more »

A PCB virgin no longer

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Well, it’s happened. My first PCBs have arrived. Now it’s just a matter of summoning the courage to solder on the parts and see if it works. This is the board I designed as part of my Eagle vs KiCad series. It breaks out a Centronics-compatible DB25 socket, with the data lines being driven by a shift register. There’s a… Read more »

Serial to parallel the hard way

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I kind of miss making hard copies of my program listings on a dot matrix printer. There’s something contemplative and satisfying about waiting for the printer to finish its buzzing and chattering so that you can pore over the code and find that bug. Also, printouts on continuous listing paper with holes down the sides feel like real computing. It… Read more »

PCB design: Eagle vs KiCad – a different direction

[Eagle vs KiCad part 8] So, as I mentioned in the previous post, I’ve decided to change direction slightly. Rather than continuing with the HexMonitor project to a completed and fabbed board, I’m going with a slightly simpler project. The reasons are two-fold: first, the HexMonitor board is sufficiently complex that I figured it had no chance of working, this being… Read more »