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Questions tagged [zx-spectrum-clones]

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39 votes
2 answers
12k views

Can a USR command damage a ZX Spectrum?

I recently came across this magazine snippet; specifically this section: Aprovechamos para avisar a los usuarios del Inves, que nos ha Ilegado el rumor de que haciendo: BORDER 5 RANDOMIZE USR 4665 ...
wizzwizz4's user avatar
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36 votes
5 answers
4k views

Which ports are which on this Soviet ZX Spectrum clone?

Today I got my (first) Soviet ZX Spectrum clone. The person who sold it to me had inherited it and had no idea how it worked. It seems to be a home-made clone, rather than a factory-built one. See ...
harlandski's user avatar
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14 votes
1 answer
747 views

Why does this Soviet floppy controller have two windows in the chip package?

This is a picture of the KR1818VG93, a Soviet clone of the WD1793 floppy controller. It was used in some Spectrum clones: (source) What are the two windows in the chip package for? They appear to ...
user1908704's user avatar
14 votes
1 answer
978 views

Did the Samsung SPC-650 have any hardware or firmware differences to the genuine Sinclair Spectrum+?

There was a clone of the Sinclair Spectrum+ in South Korea called the Samsung SPC-650 that looks identical to original British version with just an extra model number/logo. It even retains the ...
hippietrail's user avatar
  • 6,654
12 votes
2 answers
695 views

Did any ZX Spectrum clones use a 16 bit datapath between memory and video generation?

On the Commodore 64, there is a 12 bit datapath between memory and the VIC II: the ordinary screen data, which is in DRAM, and another 4 bits which comes from another SRAM chip which may be paged into ...
Omar and Lorraine's user avatar
10 votes
2 answers
2k views

How compatible is the Leningrad clone with the "original" ZX Spectrum?

In Leningrad they developed a clone of the ZX Spectrum, replacing the ULA by some TTL logic. Some of my speculations: In the USSR, the analog TV sets used SECAM, not PAL, so I imagine that the ...
Omar and Lorraine's user avatar
9 votes
2 answers
1k views

Spectrum clones 512x192 mode usable text resolution

The original ZX Spectrum has a resolution of 256x192, for 32x24 text. Some later clones add a 512x192 mode. The most obvious thing to do with that is try to display 64x24 text. According to https://en....
rwallace's user avatar
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9 votes
3 answers
592 views

ZX Spectrum - guidelines for porting to PC and more are appreciated

I want to make a surprise for my father. Back in the 80s my father made a game for a custom clone (called Santaka) of the ZX Spectrum. I have all the digital files needed for it to work, but I'm ...
Sir Muffington's user avatar
8 votes
1 answer
910 views

What computer is this, a clone of a ZX Spectrum?

Recently I stumbled over this article with an interesting teaser image. It shows some home computer, presumably of the eighties. Unfortunately the image is too blurry to read the keywords on the keys: ...
the busybee's user avatar
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7 votes
2 answers
1k views

Did any ZX Spectrum clones use the Z80's interrupt mode zero?

The standard Sinclair ZX Spectrum only used mode 1 and mode 2 interrupts but the Z80 also has a mode 0 interrupt that the original Speccy never used. But there were many exotic clones of the ZX ...
hippietrail's user avatar
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7 votes
2 answers
422 views

Details of ZS Scorpion port 0x1ffd

There's this page about the ZS Scorpion, and I'm reading about the way bankswitching works. Port 0x7ffd is the same as on western ZX Spectrums, but to double the amount of RAM to 256k and also the ...
Omar and Lorraine's user avatar
7 votes
1 answer
421 views

What are the differences between Leningrad-1 and Leningrad-2?

From Planet Sinclair Leningrad-1: A simple and cheap machine, this Spectrum clone acquired widespread popularity. Not very Spectrum-compatible, due to the way the machine was designed. Leningrad-2: A ...
Omar and Lorraine's user avatar
6 votes
4 answers
1k views

Fire button of Timex TC/TS 2068 Joystick

These pages wos and timex.comboios.info suggest the fire button of the Timex TC/TS 2068 joystick is read at bit 4. Input: bit D0: up (0=active) bit D1: down bit D2: left bit D3: ...
Rui F Ribeiro's user avatar
6 votes
3 answers
2k views

Can a Harlequin ZX Spectrum clone be modifed to run CP/M?

The ZX Spectrum (and therefore the Harlequin) has its ROM from $0000 to $3FFF, while RAM further up to $5AFF is used for the screen (see Memory-Map). As CP/M expects RAM from $0000 upwards the two are ...
Paul Humphreys's user avatar
6 votes
3 answers
756 views

How does DRAM refresh work in the Leningrad?

The Leningrad uses the КР565РУ5 chip, which is the same as a 4164. It contains 64kbits of DRAM, and the datasheet says that each of the 256 row addressed need to be strobed every 4ms. I can see how ...
Omar and Lorraine's user avatar
6 votes
1 answer
330 views

How exactly does Leningrad contend the memory?

From what I understand of this answer, the Leningrad delays the Z80 during the M1 cycle so that the video generation circuitry can do its thing. I can see how M1 is "latched" (don't know if that's ...
Omar and Lorraine's user avatar
5 votes
4 answers
850 views

How did the Spectrum clones with TR-DOS and paged memory load and run code files from disk?

I've been playing with Spectrum emulators, their file formats and some reverse engineering tools recently. Thanks to this forum, I was able to parse the TR-DOS disk image format and find the bytes of ...
hippietrail's user avatar
  • 6,654
4 votes
2 answers
313 views

How do I use the extra commands in the Spanish version of the 128k Spectrum ROM?

The Spanish Inves/Investronica version of the 128k Sinclair Spectrum had a rather different ROM from the English 128k Speccy. Error messages were in Spanish, there were extra letters and punctuation ...
hippietrail's user avatar
  • 6,654
4 votes
1 answer
314 views

Why does this ZX Spectrum clone have an extra 2K PROM on the Farbplatine?

While researching this answer, I discovered two East German clones, the Ilmenauer one and this one from Jena. (There is at least one other design from this same region, from Erfurt, I have not looked ...
Omar and Lorraine's user avatar
3 votes
2 answers
983 views

What file formats were used for binary executable files on later Sinclair ZX Spectrums?

The last official version of the Sinclair ZX Spectrum was the +3, released after the company was owned by Amstrad. It included a 3-inch floppy disk drive as used on other Amstrad computers. But even ...
hippietrail's user avatar
  • 6,654
3 votes
1 answer
319 views

Where can this "boot.B" file be coming from on this Spectrum TR-DOS disk image?

After working on some tools that parse the TR-DOS disk image format .TRD files for a while I just noticed that one of the game disk images I had downloaded "La Abadia Del Crimen", only has three files ...
hippietrail's user avatar
  • 6,654
3 votes
0 answers
146 views

Do we know any estimate of how many Sinclair ZX Spectrums, clones, and compatibles were made in the world?

The original ZX Spectrum was made by Sinclair and then by Amstrad in the UK. There were official versions also in the US, Europe and even India. There were very many clones and compatibles made in ...
hippietrail's user avatar
  • 6,654
2 votes
1 answer
244 views

Are the last 4 bytes in .SCL disk image files for Spectrum clones meaningful or spurious?

I recently added support for .scl images files to my Ghidra module which already supported .trd images. They are both representations of TR-DOS floppy disks as used mainly on Spectrum clones from ...
hippietrail's user avatar
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