Dear All,

almost two years later – time for an update regarding my 8-bit super-power machines. Well, they are naturally 8-bit on their serial communication ports, but some are XXL-wide internally. But all are from pre-1990.

As said in numerous super-niche and uninteresting posts here on EB, I was trying (and done - wife is happy!) to assemble my dream computers of the 1980s. These were (and still are, of course): IBM XT (5160), TI99/4A, Amstrad PCW 9512 (Joyce). The “stories” were (repeatedly) told, just to recall again : The IBM is simply beautiful. Everything. I was allowed to touch its case in 1985, but that was it. The 99’er impressed me so much in magazine advertisements back in 1984: The shiny case, so nice extensions and overall concept. The Joyce was my wife’s and my "theses maker", but more importantly, a true CP/M machine! In addition, back then, I owned a Sinclair ZX Spectrum and a ZX81 – learned BASIC and Z80 machine code on these beautiful machines. Money was an issue, and my dream systems were simply money-galaxies away. I also heard of Atari's – 1040s that is – but they were again so out of my universe - and had these totally crazy 32-bit 68000 Motorola CPUs, really nobody would ever need …

As per my last post in this thread here, I had my ZX Spectrum and ZX81 repaired and up and running again, also the IBM XT, and had purchased one LEGO Interface A (#9750). And as told elsewhere, I found three Atari 1040 STFM (ready to go into the university’s dumpsters), and in summer 2024, a TI99/4A in the US (while being there). No idea, why customs did not freak out when reentering Germany … Then there was a BL offer: €50 for another #9750, I could not resist. And in late 2024, I found an Interface B (#9751) for €80 …

All machines can connect to one of the two Interface A boxes, which meant to make some extra hardware, as TLG only endorsed 5 computer systems for their DACTA Technic Control educational sets. Evan(@evank) knows much more about this, and his website (https://www.brickhacks.com/) is full of information in this regard. I took Evan’s challenge seriously and made these little extra hardware boxes only with pre-1990 electronics. OK, one or even up-to 3 TTL chippies was all I had to use, when I found free I/O port addresses accessible via native BASIC commands/functions on the respective machines. Only for the ZX81 I had to free memory addresses, since the built-in BASIC interpreter has no IN/OUT, but PEEK/POKE. Selecting one computer for connection with a #9750 box is simply done with a little customized RS232 switching boxes; 9 wires are enough (GND + 8 data lines). The #9750 opto-couplers are fed with an extra +5V line – that is the customization of the RS232 switch boxes.

All that meant: 2 years of continuous “rearrangement” (cutting and extending) of my shelves, LEGO layout, data lines and power feeds. This as well has come to a sort of final state (but who knows … I am just thinking about … oh well, we’ll see ...)

The entire Mindstorms section including the Cybermaster PBrick are talking via (Ser2)USB with the Toshiba Satellite hiding under the XT. In addition, the Spybots are hooked up via Ser2VLL. Due to space restriction I made these pull-out boards for the Toshiba, Atari, TI99, and one Interface A. When every shelf is fully puled-out and all systems are running, I feel like being in heaven, the humming sounds and smell alone makes me very happy. Yeah, crazy, know. But: I don’t care being crazy. It keeps me off the streets and the bad guys.

Here are some photographs – as well as the current power, data, and video feed schematic. There are several video-, parallel port, and remotely controlled power switches … and tens of meters of video, data, and power cables of course. I like wires: They begin somewhere and seem to go somewhere …

These are with the shelves retracted, all of them computers:

Just the IBM, Joyce, and Toshiba:

Interface A/2, the Sinclairs, the Atari, and the 99er:

This is when I "work" - all shelves pulled-out; from the left ...

... and from the right:

A close-up on the Interface A/2, the Sinclairs and Joyce; all can talk to #9750/2; the switch box at the top right takes care of that. The Sinclairs share one custom interface placed into the Sinclair ZX Printer, so that all five (Joyce, 2xZX, Atari, and 99er) are happy: 

This is the "telescopic" drawer system I used - they extend fully, so that the shelf space (the final frontier) can be used entirely. The USB cable attaches to the single right port of the 4090; there is a USB hub hidden somewhere to the left of the IBM, so that the LEGO camera, USB IR tower, and serial IR tower (via USB2Ser adapter) can communicate with the Satellite. The Spybots have their own LEGO Ser2VLL adapter plugged into the single serial port of the Satellite:

 

Pre and post Mindstorms (Control Center II, Control Lab, Code Pilot ...) and Mindstorms close-up. All interfaces are remotely controlled via QBASIC; I am working on a Code Pilot/QBASIC program, so that programming the Code Pilot becomes a little more comfortable. 

Cables - another look behind the scenes:

Since I swiftly forget what I wired - I need the cheat sheets for data/video/and power control. The whole shoo bang is powered via wireless switches as I'll never reach the power lines by hand, there are a) simply too many and b) they are all hiding ...

And finally, here are the addresses I use to access the parallel interfaces taking to #9750/1+2 from BASIC (QBASIC, Mallard BASIC, GFA BASIC, ZX Spectrum BASIC, ZX81 BASIC, TI99 Extended BASIC:

This is it for the moment

All the best,
Thorsten

Edited January 5Jan 5 by Toastie

I approve! Great work. :)