Spectrum Computing

Thanks for updating the info. I was looking to get the new version but the link looks like it's still pointing to archive.org and can't find the file. Is there any mod magic that needs to happen for the update to become live ?

Thanks.

Thanks for checking Mark. I'll build a version of it when I get chance and see if it works as expected.

Thanks for checking that :) I think that finishes what I can do from the photos and without having the actual hardware in front of me. I've updated the schematic and the revised version is here: https://github.com/ZXQuirkafleeg/ZX-Interspec/blob/main/Interspec%20v0.2.pdf Most of it is fairly straigh...

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.

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 connect...

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 ge...

Really pleased the magazine article was of some use to get started. Brilliant to see the OCR copy of the full manual. I'm with Namtip on the photos. If you have chance to take some photos of the PCB, it would be good to see if we can reverse engineer it. The magazine articles mention a board with 10...

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.

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 fi...

Hi Both, Thanks for your couple of replies. Pulled the ROM and ULA, earlier today, which were in sockets. Overcurrent limit stopped tripping and, long story short, the ULA 5C112 appears to be faulty. I've now replaced on a temporary basis with a 6C version from another spectrum. The machine now powe...

Hi, I'm looking for a bit of help with a faulty spectrum. I've been given an Issue 2 48K Spectrum with a PSU fault. If I connect it briefly to a bench PSU it hits a current limit of around 800ma. I've not kept it on for more than a few seconds as I don't want to inadvertently damage anything more. I...

No worries. Hopefully the Interface E schematic is of some use. It's not very complex but it does work well. I've got a version and PCB for my RC2014 based spectrum which I'll publish when I get some time. The Cygnus universal interface looks good - I've not seen it before. I'll add it to the ever e...

Thanks - I want to get the write system working when I get a little time. The PCB should straightforward to adapt to swap the 40 pin RC2014 connector to a spectrum edge connector. It may need some small layout changes to ensure the tracks can be routed in the space available. The PCB also works with...

Hi, Over the past few months, when I get a little spare time, I've been working on producing a (rough) functional copy of the interface 1 ULA in VHDL. It's not intended to be a copy of the original but it should, ultimately, function in the same way. Currently it works well and loads files from an O...

Hi, Thanks for the feedback. I've updated the schematic so it now aligns to the original. The logic etc still the same but I've removed the resistor and replaced the 28C64 with the original 2516 EEPROM along with the mixed up address and data lines. This means the circuit will only work with the ori...

Hi, Schematic can be found here: https://github.com/ZXQuirkafleeg/ZX-Interface-E/blob/main/PCB/RC2014%20-%20Interface%20E-%20Original/Interface%20E%20-%20original.pdf and the original and decrypted ROMs here: https://github.com/ZXQuirkafleeg/ZX-Interface-E/tree/main/ROM A couple of notes about the s...

I have a schematic for the Interface E and have built a working copy for a RC2014 format spectrum. I'll dig it out and post a copy over the weekend. It's an interesting design. On my original Int E board, the 2K ROM address and data bits are swapped around. I assume this is to make the PCB layout ea...

I have just added the details of a DivMMC disk drive clone for the system. The Github is here: https://github.com/ZXQuirkafleeg/ZX-DivMMC and contains the PCBs, CPLD and system files.

I hope it is of some use!

I've added a few more repositories to the github site: ZX Development Board ( https://github.com/ZXQuirkafleeg/ZX-Development-Board ) - An EPM7128 CPLD development card which is useful for prototyping peripherals which use ROM and RAM. Template Quartus VHDL design file included. ZX Bus Adapter ( htt...

Can you post some pics of it? It would be nice to see what you did and how it looks :) It sounds interested, but I'm having trouble getting my head around what you've done exactly and how it works. Is it the board at the back of this picture? It looks pretty cool. Does it have the capability to map...

I have developed a ZX Spectrum implementation based on the popular RC2014 bus format format. The primary purpose was to provide a flexible spectrum hardware development environment – and one where I didn't blow up my ageing original spectrum hardware in the process. i generally like the RC2014 form ...

That's great - thank you

Does anyone know where i can get an image of the Unidos rom for the MGT Disciple disk interface ? I've taken a look but can't seem to find a copy.

Many thanks.

Hi, I've been using realspectrum to understand some hardware functionality - and it's a great reference. I've been looking for some source code for it but with no luck. Does anyone know if the source is available ?

Thanks!

Hi flatduckrecords , Sorry for the delay in replying but I'm away with work at the moment. Many thanks for all the pics - especially the backlit ones which are great - and the insights on how the not hidden/rem command works straight off. I'm running though the pics at the moment and trying to figur...