Monthly Archives: February 2022

Elliott 405 – a simplified representation

There’s something about  this brochure that just screams 1950s. The graphics on the cover, for instance, are straight out of Mad Men. ‘A simplified representation of the National-Elliott Electronics Data Processing System’ is the kind of brochure you wouldn’t think was necessary – or appropriate – for this kind of machine. The Elliott 405 wasn’t something you bought on a… Read more »

Elliott 405 cheat sheet

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In among Big Doug’s small but treasured trove of documents relating to the GPO’s National-Elliott 405 computers is a small yet fascinating document that seems to be part cheat sheet and part marketing material. The six-page, fold-out booklet is handily sized to fit into a shirt pocket, along with your pocket protector and 6H pencil. Most of the National-Elliott 405… Read more »

Zolatron 64 ROM code – write, debug, repeat

With the basic hardware of the Zolatron 64 6502-based homebrew computer working fine, I’ve been spending most of my time on the ROM software. It turns out that writing an operating system in 6502 assembly code is harder than you might think. Well, anyway, it’s harder than I thought. But first… A quick catch-up on the state of play with… Read more »

Raspberry Pi serial and the importance of pullups

Another day, another lesson learned. My Zolatron 64 6502-based 8-bit computer uses serial for its main I/O. One day I may add video output and keyboard input. But for the time being, I’m happy to talk to it via a terminal from another machine. So far, that other machine has been my electronics workbench computer – a LattePanda Alpha. And… Read more »