Spectrum Computing

Kiwi wrote: ↑Sun Jan 28, 2024 8:17 pm Thanks ! One final thing,where does Pin 10 of the ADC0809 connect to on the LS93 ? I think it's probably pin 8 or 9 on the LS93 but could also be pins 11, 12, 14 or 1.

Pin 10 of the ADC goes only to Pin 9 of the LS93.

Hi, that's great - thanks again for the info and pics. It looks like the NAND gate is simply used as a buffer for the CPU clock signal and the rest of the inputs are pulled up via the 2K2 resistor. The adjacent cap now looks like a decoupling cap. Would you mind checking if pins 1 and 12 are connec...

1024MAK wrote: ↑Sun Jan 28, 2024 6:02 pm If the diodes have the same colour bands (yellow, brown, yellow, grey) as the diodes on the bottom right on this ZX81 board, then they are 1N4148 diodes.

Mark

Yes, thanks. I didn't notice the grey band before, double checked and they are the same

Hi, that's great - thanks again for the info and pics. It looks like the NAND gate is simply used as a buffer for the CPU clock signal and the rest of the inputs are pulled up via the 2K2 resistor. The adjacent cap now looks like a decoupling cap. Would you mind checking if pins 1 and 12 are connec...

Thanks for the all photos - they're really useful. I've created a first cut of a schematic https://github.com/ZXQuirkafleeg/ZX-Interspec/blob/main/Interspec%20v0.1.pdf . It's based your photos but there are a few gaps: 1) Diode types, cap values and tx types are all estimates. It would be good to g...

Stefan wrote: ↑Sun Jan 28, 2024 12:13 pm My point was more my surprise at finding that until two years ago the original producer was still trading and selling these.

Ah, Yes, I see now, sorry, no offence meant, just didn't spot the date. Wow, if only I had cleared the loft a couple of years earlier...

You seem to be just a few years too late. www.dcpmicro.com takes me to a new standard getting started Wordpress page, that does contain in the lower left corner: TOO LATE? - er that's why they call it RETRO COMPUTING nowadays :D Using the wayback machine https://web.archive.org/web/20230128190031/h...

Hi Kiwi, Thanks for that. I'll take it to bits and see if I can help resolve the questions, certainly with the component types and values. :) Thanks for the all photos - they're really useful. I've created a first cut of a schematic https://github.com/ZXQuirkafleeg/ZX-Interspec/blob/main/Interspec%2...

Here's some photos of the PCB and chips. I'm working on a reverse engineering diagram too. Hope they help you. https://i.postimg.cc/ctCt4dYC/PXL-20240117-143259862-MP.jpg https://i.postimg.cc/0rywC03v/PXL-20240117-143310858-MP.jpg https://i.postimg.cc/KRd3xSYc/PXL-20240117-143325749-MP.jpg https://i...

I've just uploaded the video to my YT channel, you can view it here:


Hope you find it useful

OK, just spent many hours OCRing, editing and remaking the user guide. I've created a page about the INTERSPEC on my website so you can download a PDF version there. I'll be building a test rig and programs to test it with and putting my results there. Hope this helps more INTERSPEC users. https://c...

UPDATE: Thanks to that document via kiwi, I have begun basic testing of the module - IT WORKS! I managed to find a reference to the original documentation and I have now been sent a scanned copy. I'm in the process of OCRing it and will create a WORD / PDF version of it which I will share. I'm also ...

This is relevant to my interests so I'll be watching this thread with interest. I want to be able to do some simple home automation tasks, log temperatures etc. Does anyone know if there is any hardware documentation for this device? I'd love a circuit diagram to see how they did it. I don't suppos...

Such a cool piece of equipment, the idea of being able to control something really appeals. I hope you get it up and running. I’ve long wanted to do a similar thing, maybe one day I’ll get around to it. I'm sure I will, somewhere in the boxes from my move 20+ years ago, the instructions are still t...

Kiwi wrote: ↑Mon Jan 15, 2024 11:02 pm And take a look at an old issue of ZX computing http://www.retro8bitcomputers.co.uk/Mag ... g&issue=14. Page 72 gives a review of the device along with a few basic programming examples.

Thanks for that too, very useful

There's a promo leaflet for the DCP devices here: https://forum.tlienhard.com/phpBB3/download/file.php?id=12348&sid=92531b17df02ac5071b7b2da0fa45324 One of the pages indicates the TTL port is at IN/OUT 95, the ADC is IN 31, Switch inputs at IN 63 and relay outputs at OUT63. You may be able to f...

Found a pic of the interface and instruction sheet.

Hi all, I have one of the DCP Interspec BUS Expansion adaptors. It provides I/O functionality for the spectrum. You can read all about it here: https://spectrumcomputing.co.uk/zxsr.php?id=1000195 I used to use this to control Meccano models - switching motors and lights on and detecting switch senso...

Hi I'm Chas, A retired TV engineer from the late 60s. Built a ZX80, then bought a speccy. Had an interface II, AMX Mouse, 2 x microdrives and wrote quite a few training manuals using TASWORD. Refitted the PCB into a full sized keyboard and it worked very well. Then I bought a PC. Boxed up the speccy...