So, as always I need to apologise for neglecting things on the site but I’ve just been so busy. Besides being busy at work I’ve also been busy in the workshop. One project that I’d like to share with you is my attempt to re-create an iconic British 8-bit computer; the Acorn System 1.
The Wiki for this computer is here: https://en.wikipedia.org/wiki/Acorn_System_1
By todays standards, the Acorn System 1 was probably less powerful than a modern calculator with only a very limited amount of RAM (just over 1K on board) and a clock speed of around 1MHz, but for many people in the 1970’s this would be an introduction to computers that would send them off on a journey that, hopefully, is still ongoing for them today.
I wasn’t rich enough to possess one of these beasts, but my brother was, and it has always held a certain fascination for me. I would see him slaving over the keypad for hours at end, with the result being a few flashing LEDs or some terrible sounding music coming from a tiny loudspeaker he’d connected to the thing. Even so, it was the most fascinating thing I’d ever seen and that wonder has stuck with me all these years. We will return to this in a minute.
A few months ago, I discovered JLCPCB. I used to create my own PCB’s but they were limited. Typically single sided and whilst you can do some really clever things making your own boards, there are just some things that are too difficult. To be able to have double sided, high quality boards with a silk screen always seemed like a very expensive luxury. I’m going to create an article on getting PCB’s made with JLCPCB. Long story short for now, I needed to order some PCB’s and though since I’m paying for postage, is there anything else I want. It was at that point that the Acorn System 1 popped into my head and I decided to slip some PCB’s that could, in theory, allow me to re-create the computer onto the order. This was a rush decision. I needed to order the original PCBs ASAP as I had a time critical job that was waiting for them, so I gave myself 24hrs to design a set of PCBs for the Acorn.
I had some hi-res pictures of the System 1 boards, and circuit diagrams, but the pictures were only of populated boards so you can’t see all the tracks and their end points and I did find some discrepancies between the board pictures and the circuit diagrams. Also, the Acorn System 1 as was, uses some chips that are not exactly modern these days, and one (or two depending on the final configuration) are all but impossible to get hold of. I will cover exactly how, what and why I did to get the PCBs created in a separate article, but suffice to say for this blog entry, the PCB’s arrived yesterday.
JLCPCB have a minimum qty of 5 boards for each design, which on the one had seems a bit wasteful; especially since I don’t even know if my design will work, BUT the boards are so darn cheap you don’t really need to worry.
So, the above picture shows the boards and the partially assembled Keypad / display board.
I wonder if this will work.