SpecNext Wiki - User contributions [en-gb]

ZX Next Clones

2026-03-23T21:15:22Z

Danboid: Add Karabas-Go Mini to list of Next ports

The ZX Spectrum Next is open hardware; as such it can be completely cloned (both the hardware based on the official schematics and the core) or its core ported to different platforms using the same or different FPGAs

== ZX Next clones ==

ZX Spectrum Next clones use the same FPGA model as one of the revisions of the machines produced by SpecNext Ltd duplicating also the corresponding schematics. In essence they are complete ZX Spectrum Nexts and their core is updated using the official core contained in the System/Next distribution.

There are two clones available at the time of writing

[[N-Go]] - The [https://manuferhi.com/c/n-go N-Go] is a full KS1 ZX Spectrum Next clone coming in a full size PCB with ESP and RTC complete with 2 Mega Drive style joystick ports, an expansion port and optional custom case and mechanical keyboard. It also has the option of working as a ZX DOS using a switch in which case all the ZX Uno/ZX DOS cores are available to the user.

[[Xberry Pi]] - is a ZX Spectrum Next clone with a PCB roughly the same dimensions as a Raspberry Pi 3 without extra hardware like the ESP, full size expansion bus and extra joystick port (they are however fully expandable).

== ZX Next core ports ==

The Spectrum Next core has been ported to several different FPGAs with varying degrees of completeness and compatibility, including:

[[ZX-DOS]] - FPGA-based hardware recreation of the ZX Spectrum, created by [https://www.antoniovillena.es/ Antonio Villena].

[https://zxdos.forofpga.es/ ZX-DOS+ and gomaDOS+] - ZXDOS+ and gomaDOS+ are the continuation of ZX-Uno. They are the same machine in a different case.

[https://github.com/MiSTer-devel/ZXNext_MISTer ZX Spectrum Next for MiSTer Platform] - an incomplete ZX Next core for MiSTer FPGA compatible systems].

[https://antoniovillena.com/product/zxtres/ ZXTRES] - The ZXTRES, ZXTRES+ and ZXTRES++ are Next clones with several alternative cores.[https://github.com/zxtres/wiki/wiki ZXTRES wiki.]

[https://github.com/andykarpov/karabas-go Karabas-Go] - A Spartan-6 based devboard with a fully working Spectrum Next core.

[https://github.com/andykarpov/karabas-mini Karabas-Go Mini] - A cost and size reduced version of the Karabas-Go devboard.

[https://www.arananet.net/pedidos/product/unamiga-a500-header-compatible-with-a500-and-checkmate-1500-cases-pre-order UnAmiga] and [https://www.arananet.net/pedidos/product/unamiga-reloaded-standalone-preorder Unamiga Reloaded] have ZX Next cores.

MAME:Installing

The core of the Spectrum Next hardware is licensed under the GPLv3 free software license which has enabled the production of several compatible (and partly compatible) clones or ports, including:

[[N-Go]] - The [https://manuferhi.com/c/n-go N-Go] is a full ZX Next clone complete with 2 Mega Drive style joystick ports, an expansion port and optional custom case.

[[Xberry Pi]] - an affordable Next clone with a PCB roughly the same dimensions as a Raspbery Pi 3.

[[ZX-DOS]] - FPGA-based hardware recreation of the ZX Spectrum, created by [https://www.antoniovillena.es/ Antonio Villena].

[https://zxdos.forofpga.es/ ZX-DOS+ and gomaDOS+] - ZXDOS+ and gomaDOS+ are the continuation of ZX-Uno. They are the same machine in a different case.

[https://github.com/MiSTer-devel/ZXNext_MISTer ZX Spectrum Next for MiSTer Platform] - an incomplete ZX Next core for MiSTer FPGA compatible systems].

[https://antoniovillena.com/product/zxtres/ ZXTRES] - The ZXTRES, ZXTRES+ and ZXTRES++ are Next clones with several alternative cores.[https://github.com/zxtres/wiki/wiki ZXTRES wiki.]

[https://zxuno.speccy.org/ ZX-UNO] - A Next clone in a Raspberry Pi form factor with composite video output. Very old ZX Next core.

[https://github.com/andykarpov/karabas-go Karabas Go] - A Spartan-6 based devboard with a fully working Spectrum Next core.

[https://www.arananet.net/pedidos/product/unamiga-a500-header-compatible-with-a500-and-checkmate-1500-cases-pre-order UnAmiga] and [https://www.arananet.net/pedidos/product/unamiga-reloaded-standalone-preorder Unamiga Reloaded] have ZX Next cores.

2025-07-31T10:08:53Z

Danboid: Edit PS/2 section to make it clearer how to enable keyboard

2024-05-30T10:43:25Z

Danboid: Tweak J7 description

The [https://github.com/DonSuperfo/Xberry-Pi Xberry Pi] (XBP) is a ZX Spectrum Next clone using a PCB that has approximately the same dimensions as a Raspberry Pi 3.

This page documents key info specific to the XBP that is not covered on its github page.

=== Differences between the XBP and the Spectrum Next KS1 ===

The XBP is largely identical to a Spectrum Next KS1 but with the following differences:

* The XBP uses the much smaller Raspberry Pi 3 SBC form factor.
* No expansion slot.
* No integrated keyboard. A header is provided for connecting a Matrix keyboard.
* No second joystick port. A [https://wiki.specnext.dev/images/0/07/Xberry-Pi-joystick-splitter-v4.png joystick splitter is available] for a second joystick port.
* No footprint for adding a second SD card.
* No reset or NMI (Non Maskable Interrupt) buttons are on the XBP PCB. [https://github.com/DonSuperfo/Xberry-Pi/blob/main/Issue%204G/Xberry%20with%2048K%20Keyboard.JPG Footprints are provided] for you to add these buttons if desired but these functions can be accessed via function keys.

A PS/2 splitter cable can be used to attach a PS/2 keyboard and mouse simultaneously.

=== PS/2 input configuration ===

You cannot use your PS/2 keyboard after booting a new instalation of NextZXOS on a XBP. This is because NextZXOS is designed for use on official Next computers and NextZXOS defaults to using the integrated keyboard. To fix this you have to edit '''MACHINES/NEXT/CONFIG.INI''' on your NextZXOS SD and change the ps2 line:

ps2=1

To enable PS/2 mouse input, you must enter the Next boot configuration menu by pushing the '''SPACE''' bar during boot and check the PS2 option is set to Mouse.

=== Ports and headers for XBP 4G ===

Note that some of the ports and headers have different names on older revisions.

[[File:Xberry Pi Issue 4G assembly Top.jpg]]

* '''BT1''' - RTC battery clip location, not attached in above picture
* '''J1''' - Micro USB power input
* '''J2''' - HDMI digital AV output
* '''J3''' - PS/2 keyboard/mouse input
* '''J4''' - 3.5 mm headphone output
* '''J5''' - Sega Mega Drive / Genesis compatible joystick port
* '''J6''' - Raspberry Pi Zero accelerator header
* '''J7''' - Matrix keyboard headers plus reset, NMI and divMMC NMI button headers
* '''J8''' - WiFi adapter header
* '''J9''' - JTAG debugging header
* '''J11''' - Joystick select header
* '''J12''' - VGA video output header
* '''J15''' - 3.5 mm microphone input for a cassette tape player

=== Modifying RPi 3 cases ===

You should be able to fit the Xberry Pi into most cases designed for the RPi 3 after removing its VGA output board but one or two adjustments will be required before the PCB will fit into most Rpi 3 cases properly. You will need to use a grinder or a similar tool to create a new hole for the XBP's mic input jack and in some cases you may also need to remove a bit of plastic that separates the network socket from the USB ports, if there is one present on your case to make room for the joystick port.

=== Recommended power supplies ===

Power supplies known to work with the RPi 3 should be good enough to power the XBP such as the official RPi 3 USB power supply. Your PSU must use a Micro USB connector and provide at least 5V 2A for reliable operation.

=== Known hardware issues and fixes ===

The XBP suffers the same HDMI backpower issue as the Spectrum Next KS1. This issue causes the XBP to fail to power cycle correctly when using HDMI. The workaround is to buy an inexpensive HDMI splitter which allows you to disconnect your XBP from your HDMI display at the push of a button without having to remove and re-insert your HDMI cable every time you want to power cycle the machine such as when you want to enter the boot configuration menu, update your firmware or boot a different core.