Questions tagged [zx-spectrum-clones]

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37
votes
2answers
11k 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 ...
34
votes
5answers
3k 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 ...
10
votes
1answer
273 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 ...
9
votes
2answers
680 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....
8
votes
2answers
1k 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 ...
6
votes
1answer
125 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 ...
5
votes
3answers
288 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 ...
5
votes
2answers
882 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 ...
4
votes
2answers
162 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 ...
3
votes
2answers
566 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 ...
3
votes
1answer
98 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 ...
2
votes
1answer
90 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 ...
2
votes
0answers
81 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 ...
0
votes
1answer
100 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 ...