This is my Orton 3CX (3C eXpander) board. It's a i/o port expander for the Orton 3C I bought at the #RC2014 Assembly last weekend. It has a buffered data bus and port decoding for eight input and output ports, and lots of space for devices and connectors.

Time to get the soldering iron out.

A bit of graphics programming on my Z80 today.

After a few "teething problems" my Orton 3C is working :-)

A good morning's work, now time to stop for lunch :-)

Looks like I have some soldering to do tomorrow :-)

I'm looking forward to meeting all the RC2014 enthusiasts who are coming to the inaugural RC2014 Assembly at @tnmoc.bsky.social today.

While not as spectacular as @breakintoprogram.co.uk 's 3D code, I've got my 3D rendering code to work. This started out as a fully featured 3D renderer in C, which I simplified into Algol-60 (for the 803's plotter) and then back to C for my Z80 RC2014 CP/M machine.

Ext kits are going to the RC2014 Assembly event at the National Museum of computing on Saturday. We will be taking our RC2040 and Pico RomWBW kits to sell. www.tnmoc.org/events/2025/... for tickets.

I picked up a few conker the other day while out for a walk. They are now in the fridge to make sure they have a Winter and are ready to germinate in the Spring.

Some detective work needed to find the source of these spurious bit eight holes being punched on what should be a five hole tape. The tape viewer code only shows eight hole tape if any bits above bit five are set, so this should show as five hole not eight hole tape.

After a couple of false starts I've got the 803 running my Algol 3D rendering programme. The cube corner coordinates (before applying the viewing transformation) were also computed by an Algol programme.

I've spent a few days translating bits of this github.com/michalzalobn... into Algol-60 to run on the Elliott 803. And at last it is working, but you have to be patient as it takes 30 minutes to compile and run the program to just draw this cube. More frames will only take about 12 minutes each ;-)

Do you have an RC-2014 (or RCBUS) System ? Next Saturday's RC2014 Assembly at TNMOC is a chance for you to show it off and meet other owners to talk about all things Zilog CPUs. Also we have a special guest joining us via Zoom. Tickets still available from www.eventbrite.co.uk/e/rc2014-ass...

had an extraordinary day at @tnmoc.bsky.social with folks from @recursecenter.bsky.social - so so many exhibits, and extraordinarily kind and patient volunteers our whole group was mesmerized by @peteronion.bsky.social's work on the "Elliott 803" - his deep knowledge of it, and incredible emulator.

Oh Dear: "Take your programming skills up a notch" and "Using generative AI tools such as ChatGPT to write software" do not belong together. I fear someone has fallen for all the AI hype !

It took me about 1 dayto translate this HCode programme into C, then 3 days to debug it! Eventually I had to add a lot of printfs to the C version and equivalent outputs to the HCode version and then used diff to find out where the game state diverged. But now it runs on my RC2014 CP/M machine :-)

If only someone had invented "programme layout" in the 1960s then reverse engineering this code would be much easier !

I'm back to playing with my RC2014 CP/M machine in preparation for the RC2014 Assembly event on the 20th. Here is the PI calculating algorithm we've recently been playing with on some of the museum's machines implemented in Hi-Tech C. 3:25 for 400 digits.

There's still time to book your place at the forthcoming RC2014 event at The National Museum of Computing. It's a chance to meet other RC2014 builders and users, or to learn about RC2014 and similar systems before deciding to buy and build your first one. www.tnmoc.org/events/2025/...

Today I've been updating the syntax diagrams for my 803 Assembler.

Our next Raspberry Jam is a "Potton Pi and Pints" at the family-friendly pub The Rising Sun in Potton Bedfordshire on 1st November 2025. Sign up to our mailing list for more information when we publish it! :-) #raspberrypi #raspberryjam #bedfordshire #computing #electronics camjam.me?page_id=49

Finally got organised to get out and do some radio for a couple of hours this evening.

Been bogged down with a bit of code for a few days so today has been a day of domestic appliance therapy: ewbank.co.uk/products/ep1... My kitchen laminate floor has been washed and polished :-)

Seems the American Government Three Ring Circus has moved onto the streets of Washington DC 😆 Do they not realise just how they appear to the rest of the world ?

Just found these two in my somewhat overgrown flower beds in my back yard ! I've seen them once before when I came home once late in the evening .

One of volunteers @TNMOC has recreated their A-level Computer Science project from 1978. And today I've compiled and run it for them on the Elliott 803. They are very happy :-)

A blast from the past : www.macearchive.org/films/centra...

I've just been down a rabbit hole to find out what was causing this less than helpful runtime error message to be produced by some previously working wayland client code : "listener function for opcode 3 of xdg_toplevel is NULL"

Today @TNMOC we've connected up the spare console for the Elliott 803 to give it a soak test. After exercising a couple of the buttons that were making intermittent contact it is all working well.

Time to revive another old Elliott 803 programming project, at least there are some design notes for this one :-)

Has anyone else seen problems with using the stencil buffer in openGLES 3 on a Pi5 ? This should be a solid white area! Issue seems to have come with an update sometime in the last year or so. I only just noticed the issue (which is much less obvious in real use where the image is much darker).

When we last had to replace an incandescent strip lamp in @TNMOC's 803 console we decided to use LEDs and a gel filter to get the orange glow of the under run lamps. Then we were given some two new strip lamps, so we've put them in the spare console. I think we got a good colour match.

What ? Two Elliott 803s running ? The console in the background is connected to the real 803. The console in the foreground is being driven by an 803 emulator. The light flash and it makes noises but the buttons and switches have not been wired up (though they have all been cleaned and tested).

I just used the "init=/sbin/bash" magic to recover root on an old 486DX4 laptop runing SuSE 7.1 (From 2001). Amazingly the hard disk still works and it even runs Xwindows ! Sadly I can't get the PCMCIA WiFi card to talk to my HomeHub :-(

The spare Elliott 803 console has come back to life 👍But it needs some more testing before being connected to the real machine.

For those of us of a certain age : www.bbc.co.uk/sounds/play/...

R.I.P. this bulb from @TNMOC's Elliott 803's Paper Tape Reader. I'm not sure how old it was, but we've recovered another one from a spare reader. Let there be light :-)

AI confidently gets it exactly wrong ! MDA Hsync is an 8μS positive going pulse ! 🤦‍♂️

I had an idea, and here it is coming to fruition :-) www.eventbrite.co.uk/e/rc2014-ass...

Too hot to run the Elliott 803 today so we've been doing some restoration work on the spare operators console. So far we've found a dead 200µF 150V capacitor in the bias circuit for the DM160 indicators (which are triode valves).

For the person who said "You don't have letters after you name so you can't have a degree."

That was a "no-brainer" decision....

Be prepared to be amazed !!!! Try this (Not my code, but it is safe): #include <stdio.h> int a[52514],b,c=52514,d,e,f=1e4,g,h; void main(void) { for(;b=c-=14;h=printf("%04d",e+d/f)) for(e=d%=f;g=--b*2;d/=g)d=d*b+f* (h?a[b]:f/5),a[b]=d%--g; }

Local news paper proclaims "Homes mainly in the Bedford Road part of Kempston have been bit by a huge power cut (Wednesday)."

@pimoroni.com Again you have a 20% sale the day AFTER my order arrives ! 🤦‍♂️

bluetoothctl really sucks !

I'll have to wait until another day when the temperature is lower to start this again as I had to stop it after two hours run time when the Elliott 803 got a bit too warm.

I've just had one of those "What was I thinking when I wrote this code?" moments. With hindsight it turns out there is a much simpler way to do it :-)

Here @TNMOC we have a spare Elliott 803 operator's console which we have pulled from storage and have started to clean it up. Foam cleaner has done a good job at removing years of accumulated grime from the inscribed button labels.