Questions tagged [zx-spectrum]

For questions about the different versions and products of the Sinclair ZX Spectrum computer

Filter by
Sorted by
Tagged with
2 votes
0 answers
164 views

Lower RAM module design for ZX Spectrum [closed]

While the upper DRAM chips for the ZX Spectrum (4164) are more stable and still accessable, the lower DRAM chips (4116) will become a critical component in the future. One of the solutions to this ...
Pygmalion's user avatar
  • 121
3 votes
2 answers
377 views

Can anyone tell me more about flippy games?

I remember having a number of Mastertronic tape games for the Amstrad CPC 464 that could be used on a Spectrum too by using the other side of the tape. These were called flippys I believe. Was this ...
Robbie Dee's user avatar
6 votes
0 answers
205 views

How many commercial Spectrum ROM cartridges were released?

According to this site, Sinclair released a total of ten titles on cartridge: all games that were popular on cassette, and all in 1983, the year the Interface 2 was released. I know the cartridges ...
Pastychomper thanks Monica's user avatar
8 votes
0 answers
248 views

What were the licensing terms for The Hobbit? [closed]

The Hobbit was a 1982 illustrated text adventure game released initially on the Spectrum, based on the Tolkien novel of the same name. According to https://www.filfre.net/2012/11/the-hobbit/ Unlike ...
rwallace's user avatar
  • 61.1k
7 votes
5 answers
2k views

Spectrum DIY upgrade to 48K

The ZX Spectrum was initially sold in 16 and 48K versions. Every owner of the former version who continued using it, inevitably ended up wanting the upgrade to the latter. (I get the impression it ...
rwallace's user avatar
  • 61.1k
8 votes
2 answers
2k views

What does Spectrum BASIC have that ZX81 lacks?

The Sinclair ZX81 has 8K BASIC interpreter ROM; the Spectrum has 16K. What extra features does the Spectrum put in the extra 8K? The most obvious thing is commands for color graphics, which are absent ...
rwallace's user avatar
  • 61.1k
11 votes
1 answer
1k views

Using Sinclair ZX Microdrive is it possible to random access a text-file?

I wish to build a small database using Sinclair ZX Microdrive: one can think to create a text file using some simple BASIC. For simplicity let's say the record is 512 bytes in length, i.e. the same as ...
Matteo Vitturi's user avatar
5 votes
2 answers
631 views

ZX Spectrum+ 48K with faulty memory writing address

I have ZX Spectrum+ 48k (board issue 6a) with writing to memory issue. When I try to write a value by POKE command to address 49152 (C000h) then it overwrites additionally value with address 16384 (...
vikkk's user avatar
  • 51
13 votes
2 answers
1k views

What are the electrical properties of the EAR and MIC sockets on a ZX Spectrum, and can they be connected between machines?

I'm interested in the possibility of connecting two ZX Spectrum computers together using as simple an interface as possible. The ZX Spectrum has two mono audio sockets at the back labelled EAR and MIC....
knol's user avatar
  • 12k
21 votes
1 answer
1k views

How did "Super Wonder Boy (in Monsterland)" defeat the Multiface One?

The Multiface One was a memory dumper for the ZX Spectrum 48K with a button that generated an NMI to run code in its ROM that could dump the machine state to mass storage (CMT/cassette tape, diskette, ...
cjs's user avatar
  • 26.1k
27 votes
3 answers
4k views

How did ZX Spectrum games loaders prevent the use of MERGE?

The MERGE command could be used on early games to load the first BASIC program block without it auto-running, but in later games, the use of MERGE caused the machine to hang. How was this achieved?
Paul Markham's user avatar
9 votes
3 answers
571 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
9 votes
2 answers
2k views

ZX Spectrum interrupt handling: maskable and NMI

Is there a skeleton for handling the interrupt on the ZX Spectrum? Can I read it? I need the ZX Spectrum to handle an interrupt from a device and I have no idea where to start from. I like the idea of ...
ozw1z5rd's user avatar
  • 439
5 votes
2 answers
713 views

BASIC line input buffer location on ZX Spectrum

I'm currently writing a ZX Spectrum emulator (I know there are plenty, but it's a project). I'm having an issue where it keeps repeating the last key press even though I know the port lines have been ...
Stevo's user avatar
  • 161
17 votes
4 answers
4k views

Was the ZX Spectrum used for serious number crunching?

From Eurogamer’s obituary of Sir Clive Sinclair: Sinclair never intended for his computers to be games machines, but that was what the market decided they were. Within the space of a few years, the ...
user1095108's user avatar
4 votes
2 answers
307 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
  • 6,666
15 votes
1 answer
974 views

How are the extra BASIC keywords of the Timex Sinclair 2068 that the ZX Spectrum didn't have encoded?

I've read that the BASIC of the Timex Sinclair 2068 is a superset of the BASIC of the Sinclair ZX Spectrum with a few extra keywords. The extra keywords are: DELETE delete BASIC program lines, FREE ...
hippietrail's user avatar
  • 6,666
14 votes
2 answers
2k views

What is the size of the border of the ZX Spectrum in scanlines/pixels/bytes?

The bitmap area of the Sinclair ZX Spectrum is exactly 256 x 192 pixels. Surrounding the bitmap is quite a wide border area which is generally just one colour but loading and saving from tape changes ...
hippietrail's user avatar
  • 6,666
5 votes
2 answers
560 views

Does the .sna snapshot file format for Sinclair ZX Spectrum emulators support a 16k variant

I'm playing with emulator and file format programming again. One of the common game snapshot formats for the Sinclair ZX Spectrum is the .sna format. I know it comes in a 48k format and a newer 128k ...
hippietrail's user avatar
  • 6,666
14 votes
3 answers
2k views

What was Sinclair's intention with the Microdrive?

The ZX Spectrum was announced with support for both standard cassette tapes and Sinclair's new Microdrive format -- although the latter wasn't released for another 17 months. Given that the necessary ...
Den's user avatar
  • 157
4 votes
2 answers
448 views

Spectrum 128K +2 Power Supply Buzzing and over voltage

I've seen a similar question to asked here but but I'm not sure it fully addresses the issue I'm having. I'm using a PSU the same as this one from the 128K +2 According to this site, this PSU ...
iamkl00t's user avatar
  • 141
7 votes
3 answers
2k views

Is there a version of Python that runs on a QL, Speccy or a Commodore?

Does any Python port run on any Speccies or Commodores? I am hopeful about QL, since: Based on a Motorola 68008 processor clocked at 7.5 MHz, the QL included 128 KB of RAM, which was officially ...
user1095108's user avatar
32 votes
1 answer
3k views

How did the various Soviet ZX Spectrum clones support Cyrillic text?

There may be no one single answer to this question, since the various clones might have done this all in different ways. And of course, some clones do not have the Cyrillic text support at all. I'm ...
Omar and Lorraine's user avatar
33 votes
1 answer
8k views

Did John Carmack really invent "Adaptive Tile Refresh"?

John Carmack is credited with making fast-paced arcade games like Commander Keen possible on an IBM-PC that had no specialized graphics controllers suited for those, thanks to the "Adaptive Tile ...
scrØllbær's user avatar
  • 1,109
8 votes
1 answer
1k views

Why was Carrier Command for the ZX Spectrum superior to the C64 version?

The ZX Spectrum version of Carrier Command has 3D rendering, while the Commodore 64 version, despite a greater amount of RAM, was inferior in comparison. You open the in-game map and there's Google ...
user1095108's user avatar
12 votes
1 answer
1k views

Is I/O port 0xFE reserved on the eZ80?

TL;DR Following on from OmarL's comment, to the closed question, Why did the Spectrum Next choose Z80 on FPGA?: But also, the eZ80 is not compatible with the ZX Spectrum because it uses port FE for ...
Greenonline's user avatar
  • 4,356
4 votes
1 answer
373 views

ZX Spectrum coordinates to bitmap conversion subroutine acting strange

I originally posted this question on stackoverflow, but I wrote a little program that converts coordinates stored in the b and c registers of the z80 into their corresponding memory address for the ZX ...
Keolai's user avatar
  • 43
13 votes
5 answers
2k views

Compression techniques used in old ZX Spectrum tapes

Many ZX Spectrum games* (and demos) would improve loading time and save space in the tape using rudimentary compression. During decompression, the game would display "decrunching" for ...
forest's user avatar
  • 2,029
21 votes
3 answers
3k views

Is there a list of space-saving techniques for representing constants?

Since numbers in ZX BASIC are always floating point and take up 5 bytes, it's often possible to save space when representing integers by using several tokens, which take up 1 byte each. I know of COS ...
forest's user avatar
  • 2,029
4 votes
1 answer
334 views

Where can I find a copy of the HiSoft C compiler manual for ZX Spectrum?

I've been able to find the manual for the CPC version of HiSoft C, but not for the ZX. The only ones I could find appeared to have been OCRed, so virtually all of the necessary information was lost. ...
forest's user avatar
  • 2,029
1 vote
0 answers
297 views

How to save and load CSpect emulator state when emulating ZX Spectrum Next [closed]

I use CSpect emulator for playing a game for ZX Spectrum Next. I wonder whether is possible to save the emulator state to memory and load it in the future in order to have game save/load functionality ...
bobeff's user avatar
  • 563
12 votes
2 answers
680 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
8 votes
3 answers
670 views

Reading data of floppies from a ZX Spectrum Swift Disc

Back in the day when we had a Sixword Ltd. Swift Disc floppy-drive we were ahead of the game on our speccy, allowing us to use 3.5inch floppy disks. See: https://www.worthpoint.com/worthopedia/swift-...
Bruce Adams's user avatar
3 votes
3 answers
1k views

What are quick ways to load downloaded tape images onto an unmodified 8-bit computer?

There are repositories of tape software available online, for example CPC Power for Amstrad CPC machines. What is the fastest and simplest way to load such games onto an unmodified computer, with the ...
Mark Williams's user avatar
9 votes
1 answer
1k views

ZX Spectrum fuse-emulator - how to use loader/multi-file program?

I'm using fuse-emulator on Ubuntu. In a book of type-in programs, some are spread across multiple files. There is a "loader" (usually setting up graphics or some machine code parts) which ...
Brian's user avatar
  • 288
7 votes
3 answers
713 views

Why did the Vic-20 need special chips for I/O?

The Vic-20 used two 6522 VIA chips for I/O. I asked why it had two of them but thanks to a comment from Bruce Abbott, I now think that wasn't quite the question I needed to ask. What I really need to ...
rwallace's user avatar
  • 61.1k
7 votes
1 answer
893 views

What non-Spectrum computers did Sinclair sell 4 million of?

Reading Alan Sugar : The Amstrad Story, I just came across one of those little oddities that initially manifest as 'huh, wait a minute' and sometimes just mean someone has made a typo, and sometimes ...
rwallace's user avatar
  • 61.1k
9 votes
3 answers
2k views

ZX Spectrum 48k Power Supply outputting 15V

I got a working ZX Spectrum 48k (issue 6a) with the original power supply. Before hooking up the power supply I tested with my multimeter to see if it was good. The power supply specifies it outputs ...
JV Lobo's user avatar
  • 293
3 votes
1 answer
387 views

Where can I donate Old Mags and Media in bulk in UK?

I am taking advantage of lockdown(s) and scanning/imaging all old media to archive.org, but would like to donate the boxes when finished. A bit like Donating old Computer Shopper Magazines The Centre ...
D.Price's user avatar
  • 41
12 votes
3 answers
3k views

How did the ZX Spectrum avoid key ghosting?

Was the ZX Spectrum better at handling than later PCs-keyboards without having diodes in its key matrix? I encountered this comment on Y Combinator but I fail to understand it. Couldn't the Speccy ...
Dmitry Anisimov's user avatar
65 votes
5 answers
10k views

Back in 1984 I wrote some games for Spectrum - Will they still be playable?

Back in 1984, I was commissioned to write some games for ZX-Spectrum. They were sold together. To my amazement I found that someone is selling a copy online. I thought of buying it but it is in the ...
chasly - supports Monica's user avatar
4 votes
3 answers
699 views

ZX Spectrum red stripes during loading

When we load any game on ZX Spectrum from cassette player... Should red stripes move smoothly for better result or they should be static for perfect result? What is the theory?
Staglaitor's user avatar
18 votes
1 answer
6k views

Could Pac-Man be replicated perfectly on the ZX Spectrum?

We all know that various ports of Pac-Man exist but my question is just for one specific computer. Could the Spectrum, with time and proper knowledge, run the Arcade version of Pac-Man despite it's ...
Vpirate21's user avatar
  • 197
9 votes
1 answer
524 views

Was the Ram Turbo the only 3rd party Interface 2 ROM cartridge interface for the ZX Spectrum or were there others?

One of the original Sinclair peripherals for the ZX Spectrum was the Interface 2 which provided joystick ports and also a slot for ROM cartridges: The cartridges did not catch on though and only ...
hippietrail's user avatar
  • 6,666
2 votes
1 answer
629 views

Using Bresenham's circle algorithm (or another alternative algorithm) to draw an arc [closed]

I'm trying to create some graphics function for a ZX Spectrum (Z80) machine in assembler. I already have the basics except for the arc. I know that there must be some way to draw an arc using the ...
Gusman's user avatar
  • 129
6 votes
1 answer
409 views

Are all 64k x 4-bit ICs interchangeable for Amstrad-era ZX Spectrum 128k +2/+3?

There were 4 64k x 4-bit Integrated Circuit chips in the Amstrad-era Sinclair ZX Spectrum +2 and +3 models. These are known as the +2A, +2B (both +2 "black"), +3 and +3B (also both black cases). I ...
popeymon's user avatar
  • 423
3 votes
0 answers
446 views

Why did the Spectrum Next choose Z80 on FPGA? [closed]

I'm curious to understand why the Spectrum Next uses Z80 on an FPGA instead of something like at eZ80? I would have imagined they would choose the eZ80 since it is still a production part. Anyone ...
Duke Dougal's user avatar
3 votes
1 answer
313 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
  • 6,666
6 votes
3 answers
1k views

Does Sinclair Spectrum BASIC have a maximum length for one line?

I was just writing some junk Speccy Basic programs, more to see how they take up space on the +3's disk layout than to do any actual programming. But I noticed that after editing a program line to ...
hippietrail's user avatar
  • 6,666
6 votes
1 answer
566 views

What role does the 4-bit shift register play in the Leningrad video generation?

The Leningrad contains a shift register1, which I believe is loaded with data from the bitmap. This part loads 8 bits in parallel, and shifts each bit out in turn on the rising edge of a clock signal. ...
Omar and Lorraine's user avatar