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This release introduces support for Tekken Tag Tournament and five additional titles, native DB9/DB15 arcade controller support, live CRT geometry adjustment from the OSD, several audio and usability improvements, and a considerable amount of work beneath the surface.

It represents the most substantial System 12 update since the core was first released.

Tekken Tag Tournament

Reaching this point proved to be the most challenging bring-up undertaken for the System 12 core so far. Tekken Tag Tournament is not simply another System 12 title; several important architectural differences had to be understood and implemented correctly.

For those interested in the technical details, six principal issues stood between the initial implementation and a stable, playable game.

1. Protection Hardware

Tekken Tag Tournament's M8F4 ROM board includes additional programmable logic beyond the KC044 KEYCUS, requiring protection behaviour not previously needed by the System 12 titles supported by the core.

The game sends 64-bit challenges to this device and expects precise responses. The protection mechanism also interacts directly with the ROM DMA path: reading a particular address arms an alternative source for the following ROM transfer as a one-shot operation.

An incorrect response at this stage prevents the game from progressing far enough to initialise video.

The core now implements the complete challenge-and-response behaviour, matched instruction-by-instruction. This is handled algorithmically; no dumped secrets are required.

2. The Boot Signature

Tekken Tag runs on the COH-700 CPU board paired with the later SYSTEM12 MOTHER(B) motherboard revision. Its boot ROM expects the 12-byte Namco Ltd.-- signature to be present at a fixed location in main RAM.

There is, however, an interesting complication.

During startup, the boot process first clears this RAM and subsequently decompresses the game over the same area. The signature therefore has to survive the initial memory clear so that the system takes the faster "hot start" path, avoiding self-tests that our free-running sound CPU would otherwise fail.

At the same time, the signature must cease being restored immediately after the boot ROM has read it.

Allow it to persist for even slightly too long and the first 12 bytes of the newly decompressed game are overwritten. The CPU then jumps directly into the text string and attempts to execute Namc as an instruction.

The final implementation therefore preserves the signature through writes and disables the mechanism upon the first read of the relevant cache line.

3. 56 MB of ROM

Tekken Tag contains a 56 MB banked game-ROM region — twice that of Tekken 3.

This extended directly into the memory region previously occupied by the sound engine and wave ROM.

The audio data was consequently relocated to the second SDRAM device, which is one of the reasons Tekken Tag requires the 128 MB SDRAM module. The DMA address range was extended accordingly, with the changes carefully gated so that the memory maps used by all existing titles remain unchanged.

4. ROM Loader Interleaving

With the previous issues resolved, Tekken Tag would boot but subsequently report its own ROM data as corrupt.

The problem was eventually traced not to the System 12 implementation, but to the MiSTer MRA loader.

Tekken Tag was the only title in the catalogue using 32-bit word interleave maps, which resulted in half of each word being loaded as zero.

The solution uses a proven byte-interleave format followed by a small in-core byte re-weaving stage.

As a result, the catalogue now follows a simple rule: byte-interleave maps only.

14 Titles, 36 Game Versions

New in this release

• Tekken Tag Tournament — four regional versions

• Aqua Rush — including a fix for its first-boot EEPROM hang

• Mr. Driller (Japan)

• Paca Paca Passion

• Paca Paca Passion 2

• Paca Paca Passion Special

Carried forward from the 20260804 release

• Tekken 3

• Soul Calibur

• Ehrgeiz

• Fighting Layer

• Libero Grande

• Oh! Bakyuuun

• Super World Stadium '98

• Super World Stadium '99

A single featured .mra for each title is placed at the top level of Arcade, while all regional variants are organised by game beneath Arcade/\_alternatives/.

New Features — CRT Adjustment and DB9/DB15 Controllers

CRT Adjust

Analogue CRT image geometry and positioning can now be adjusted directly from the OSD.

H-Size, H-Position and V-Shift are available live from the Video & Audio page, allowing the image to be correctly positioned and sized for a particular CRT without repeatedly adjusting the chassis controls.

The implementation is based on rmonic79's MiSTer-CRT-Adjust work. Picture content is repositioned and stretched while the underlying synchronisation timing remains native, allowing adjustments to be made without the CRT losing sync.

The feature is disabled by default. If it is not enabled, video output — including HDMI — remains unchanged from previous builds.

DB9 / DB15 Joystick Support

Native user-port support has also been added for:

• Mega Drive / Genesis controllers, including three- and six-button variants

• Neo Geo / Supergun-style DB15 arcade sticks

Using an Antonio Villena splitter, two players can connect through the MiSTer user port. Select UserIO Joystick from the OSD and the controllers can be used directly in-game.

There are two points worth noting.

In-game controls work with the standard MiSTer firmware. Navigating the MiSTer OSD directly from a DB9 controller, however, requires the MiSTer-DB9 fork's MiSTer binary and menu.rbf; with that configuration, Start+C opens the menu.

The implementation also makes use of the eighth user-port line previously associated with the uncommon secondary SPI-SD add-on. Consequently, that particular add-on is no longer supported by this core. The normal MiSTer SD card slot and USB interfaces are entirely unaffected.

Audio

A C352 sound-chip latch issue that could introduce static into the audio mix has been corrected across the entire System 12 catalogue.

OSD Improvements

The Video & Audio page has returned to the menu, providing access to aspect ratio, scaling, deinterlacing and stereo-mix controls.

Updated Pause Screen

The pause and credits overlay now uses the same renderer as my other cores.

The current supporter list, updated to mid-August, is displayed using colour-coded tiers:

• Gold — Hall of Fame

• Cyan — High Score

• Green — Insert Coin

If your name appears there, you are now part of the credits running on the hardware itself.

Thank you, as always, for your support.

Under the Hood

A considerable amount of maintenance work has also taken place behind the scenes.

A number of inherited source files that were never used by this core have been removed, and the release package now follows the standard MiSTer repository structure. The result is a single \_Arcade directory that can be copied directly to the SD card.

This also provides some of the groundwork required for bringing these cores into the standard MiSTer update path.

Timing closure is clean across the build, with every core clock reporting positive timing.

Not particularly glamorous, perhaps, but precisely what one wants to see.

Current Limitations and Known Issues

Soul Calibur Music

During an A/B comparison with original hardware, we identified a small amount of static in Soul Calibur's music, together with slightly reduced fullness compared with the original board. It remains under investigation. Sound effects and gameplay are unaffected.

Mr. Driller

This release includes the Japanese version of Mr. Driller.

The US version currently exhibits an intermittent screen-flashing issue related to its display registers being rewritten every frame. Rather than include a version with a known visual problem, it will remain withheld until the behaviour is properly understood and corrected.

DB9 / DB15 Testing

The DB9/DB15 implementation has passed the available electrical and logic checks, although I have not yet completed a physical test using the splitter and arcade stick combination.

If you have the necessary hardware and are able to test it, reports in the comments would be particularly useful.

Oh! Bakyuuun

Oh! Bakyuuun continues to boot successfully into attract mode, but light-gun aiming is not yet implemented.

System 12 gun input remains on the development list.

Installation

1. Copy the release Arcade directory directly into the Arcade directory on your MiSTer SD card. The core is provided as:

Arcade-XNSYSTEM12\_20260816.rbf

under \_Arcade/cores/, with the corresponding .mra files placed alongside the existing arcade definitions.

1. Provide your own ROM ZIP files under:

games/mame/

No ROM images are included with this release.

Tekken Tag Tournament requires the 128 MB SDRAM module, as its banked game-ROM region alone occupies 56 MB.

1. Existing EEPROM settings and saved configuration data are retained and carry forward unchanged.

Build Information

Build MD5:

16743f0ddd5e4763e53137cf0b03733f

Credits

Thanks for contributions and supporting work from:

• rmonic79 & Andrea Bogazzi — MiSTer-CRT-Adjust

• MiSTer-DB9 project

• Aitor Pelaez (NeuroRulez)

• Victor Trucco

• Fernando Mosquera

• Timothy Redaelli

• Antonio Villena — splitter hardware

And, of course, thank you to everyone supporting the project. Your continued support is what makes the time spent investigating, testing and improving these cores possible.

Tekken Tag Tournament is ready. If you have a CRT, an arcade stick and suitable hardware, this is an excellent release with which to put them to use.

Please do share your results, particularly if you are testing the new controller or CRT-adjustment functionality.

There is more System 12 work to come.

Disclaimer

Legal Notice, Licensing, Attribution & Copyright Disclaimer

Project: Namco System 12 for MiSTer

Release: RELEASE-20260816

Project License: GNU General Public License, version 2 (GPL-2.0), except where individual third-party files or components state otherwise

This notice summarizes the licensing, attribution, intellectual-property, and legal information applicable to this release. It supplements, but does not replace, the LICENSE file, source-file license notices, third-party license notices, or the License, Legal, and Credits sections of the project documentation.

Where the terms of this notice differ from an applicable software license, the applicable license controls.

1. Project License

The Namco System 12 MiSTer core is free software distributed under the terms of the GNU General Public License, version 2 (GPL-2.0), except for third-party components or files that expressly identify another compatible license.

Under GPL-2.0, recipients may run, copy, modify, and redistribute the covered software subject to the terms and conditions of that license.

The complete applicable GPL license text is provided with the source distribution in the LICENSE file.

This project is derived substantially from PSX\_MiSTer and the wider MiSTer FPGA development ecosystem. The PlayStation-derived implementation provides substantial portions of the architectural foundation upon which the Namco System 12 implementation was developed.

Namco System 12-specific HDL, integration logic, memory mapping, ROM handling, I/O implementation, audio integration, timing changes, and other modifications created specifically for this project are distributed under the project's applicable GPL terms unless otherwise identified in the relevant source file.

Redistributors must comply with the applicable GPL requirements, including the requirements concerning preservation of license notices and availability of corresponding source code.

2. Upstream Projects and Third-Party Components

This project incorporates, derives from, interfaces with, or was developed with reference to several open-source projects and publicly available technical resources.

These include, where applicable:

Project / ComponentAttributionLicensing / UsePSX\_MiSTer and PlayStation-derived FPGA implementationRobert Peip / FPGAzumSpass and contributorsApplicable upstream GPL licensingMiSTer framework and supporting modulesMiSTer-devel and respective contributorsApplicable source-file/project licensesMiSTer DB9 / SNAC-related modules, where incorporatedMiSTer-devel and respective contributorsApplicable upstream licenseMAME hardware implementation and documentationMAMEDev and contributorsTechnical and behavioral reference; individual source-file licenses applyCAT702-related implementation or algorithms, where retained from the shared source baseOriginal respective authors and projectsSee applicable source-file attribution and licenseNamco System 11 KEYCUS-related implementation or algorithms, where retained from the shared source baseOriginal respective authors and projectsSee applicable source-file attribution and license

Each third-party component remains subject to the license applicable to that component or source file.

Nothing in this notice is intended to replace, alter, relicense, or remove an existing copyright notice, attribution requirement, or software license.

MAME

MAME has been an important public technical reference for referencing the behavior of Namco System 12 and related arcade hardware.

The MAME project as a whole is distributed under GPL-2.0-or-later, while individual MAME source files may be distributed under compatible licenses identified in their respective source headers.

Where information, algorithms, hardware descriptions, address maps, device behavior, or other technical information was studied from MAME, attribution should be understood as applying to the relevant MAME authors and contributors.

Unless a source file in this project expressly indicates that MAME-derived source code has been incorporated under its applicable license, references to MAME describe its use as a technical and behavioral reference rather than implying that the MiSTer core itself is MAME or is endorsed by the MAME project.

3. Namco System 12 and PlayStation-Derived Architecture

Namco System 12 is a Namco arcade hardware family that incorporates technology derived from Sony's first-generation PlayStation architecture while adding substantial Namco-specific arcade hardware.

References in this project may therefore include PlayStation-derived or compatible CPU, GPU, GTE, DMA, interrupt, memory, and related functionality together with Namco-specific ROM boards, memory arrangements, audio hardware, microcontrollers, protection mechanisms, I/O systems, arcade controls, timing behavior, and game-specific peripherals.

Namco System 12 should not be interpreted as electrically, logically, or functionally identical to a retail Sony PlayStation.

Likewise, Namco System 12 should not be treated as identical to Namco System 11, Sony ZN-1, Sony ZN-2, Taito FX-1, Taito G-NET, Tecmo TPS, Konami System 573, Konami GV/GQ, or other PlayStation-derived arcade platforms merely because those systems share architectural concepts or Sony-derived technology.

References to those systems are made only where relevant to technical comparison, shared architecture, historical context, interoperability, or development research.

4. Hardware and Technical References

References may include, where applicable:

Namco System 12 motherboards and ROM boards; PlayStation-derived processors and graphics hardware; R3000A-family CPU architecture; GPU and GTE functionality; system RAM; video RAM; sound RAM; ROM; mask ROM; EPROM; EEPROM; Flash memory; SRAM; DRAM; SDRAM; audio processors; Hitachi H8-family microcontrollers; Namco C352 audio hardware; ROM banking; address decoding; DMA; interrupts; protection devices; security devices; KEYCUS-related hardware; CAT702-related hardware inherited from related development branches; JAMMA and other arcade I/O; analog and digital controls; steering controls; rhythm-game controls; light-gun interfaces where applicable; and other game-specific hardware.

References may also include FPGA-specific concepts such as HDL, RTL, SDRAM, DDR memory, M10K memory blocks, clock domains, PLLs, bus arbitration, memory controllers, ROM loaders, timing constraints, video timing, audio implementation, input mapping, protection-device behavior, reverse engineering, emulator behavior, and compatibility testing.

These terms are used solely for identification, documentation, technical discussion, interoperability, preservation, research, and educational purposes.

5. No Game ROMs or Proprietary Game Data

The Namco System 12 core source and release are intended to contain no copyrighted commercial game ROM images, BIOS dumps, proprietary firmware dumps, disk images, CD-ROM images, security-device dumps, cryptographic keys, copyrighted artwork, music, voice recordings, or other proprietary game data.

MiSTer .mra files may identify expected ROM sets, filenames, checksums, memory regions, loading arrangements, or MAME-compatible ROM-set names. Such metadata does not itself include the referenced commercial ROM contents.

Users must obtain and use any required software, firmware, ROM images, security data, or other copyrighted material independently and in accordance with the laws applicable to them.

The inclusion of compatibility information, ROM filenames, ROM-set identifiers, checksums, memory maps, game names, or hardware information does not constitute distribution of the corresponding copyrighted game software and does not grant a license to obtain or redistribute that software.

6. Referenced Namco System 12 Software

References to Namco System 12 software may include documented commercial releases, regional variants, revisions, prototypes, location-test versions, unreleased software, partially preserved software, and other historically documented software associated with Namco System 12 hardware.

Such references are provided solely for identification, compatibility documentation, hardware research, preservation, and development.

The inclusion of a game title in documentation, source code, an MRA definition, compatibility information, development notes, or release material does not imply that:

• the software is included with this project;

• every version or revision has been preserved;

• every version or revision has been publicly released;

• every version or revision is supported by the core;

• every version has been independently verified on original hardware;

• the software may legally be downloaded or redistributed; or

• the project's developers possess or claim any rights to the game.

Regional titles, alternate names, revisions, prototypes, location-test versions, unreleased builds, and other variations remain the property of their respective rights holders.

7. Security and Protection Hardware

The broader PlayStation-derived FPGA codebase from which this project developed may contain implementations associated with protection or security devices used by other PlayStation-derived arcade platforms, including CAT702-related and Namco System 11 KEYCUS-related functionality.

Such functionality should not be interpreted as evidence that Namco System 12 software necessarily uses those devices.

Where legacy protection-related logic remains in the shared codebase but is not required by supported Namco System 12 software, it is retained as part of the shared architectural lineage rather than presented as a System 12 hardware requirement.

No manufacturer cryptographic key, proprietary security-device dump, or equivalent protected game data should be considered part of this project unless explicitly identified and legally redistributable.

Technical discussion or re-implementation of protection-device behavior is provided for interoperability, documentation, preservation, research, and educational purposes.

Laws governing technological protection measures, reverse engineering, interoperability, and preservation vary between jurisdictions. Users and redistributors are responsible for determining the laws applicable to their circumstances.

8. Intellectual Property

All product names, company names, project names, platform names, hardware names, game titles, character names, logos, trademarks, registered trademarks, copyrighted works, hardware designs, software, firmware, artwork, music, sound effects, voice recordings, audiovisual materials, cabinet designs, PCB designs, schematics, and other intellectual property referenced by this project remain the property of their respective owners.

This includes, but is not limited to, MiSTer, MiSTer FPGA, MiSTerFPGA, MiSTer-devel, PSX\_MiSTer, MAME, the MAME Project, Intel, Altera, Sony, Sony Computer Entertainment, Sony Interactive Entertainment, PlayStation, Namco, Namco Limited, Bandai Namco Entertainment, Bandai Namco Holdings, Namco System 11, Namco System 12, Tekken, Soul Calibur, Mr. Driller, and other companies, products, platforms, technologies, and game titles referenced by the project, together with their respective parent companies, subsidiaries, predecessors, successors, licensors, developers, publishers, distributors, and rights holders.

The identification of a company, project, platform, game, component, or technology does not constitute a claim of ownership.

All rights in third-party intellectual property remain with their respective owners.

9. Trademarks and Non-Affiliation

Names such as Namco, System 12, Tekken, Soul Calibur, Mr. Driller, PlayStation, MiSTer, MAME, and other referenced product, project, company, platform, and game names may be trademarks, registered trademarks, copyrighted names, or otherwise protected identifiers belonging to their respective owners.

They are referenced only where necessary for identification, technical documentation, compatibility information, historical discussion, interoperability, preservation, research, or educational purposes.

This project is an independent community-developed project.

It is not sponsored by, authorized by, endorsed by, affiliated with, or officially connected with Bandai Namco Entertainment, Bandai Namco Holdings, Namco, Sony Interactive Entertainment, Sony, Intel, Altera, MAMEDev, MiSTer-devel, or any other manufacturer, publisher, developer, project, or rights holder referenced herein, except where an actual upstream open-source licensing relationship is expressly identified.

No third-party endorsement is implied.

10. Preservation, Research, and Interoperability

The purpose of this project is the study, documentation, preservation, and FPGA re-implementation of legacy arcade hardware behavior.

The project seeks to reproduce relevant hardware behavior sufficiently for interoperability with software designed for the original hardware and to preserve technical knowledge concerning hardware that is increasingly difficult to maintain, obtain, or study.

Hardware descriptions, compatibility information, reverse-engineering findings, implementation details, timing measurements, memory maps, device behavior, and references to emulator implementations are provided on a best-effort basis.

They should not be interpreted as manufacturer documentation or as a guarantee of perfect electrical, cycle-level, timing-level, or behavioral equivalence with every revision of original Namco System 12 hardware.

Hardware classifications and implementation details may be revised as additional original hardware, documentation, PCB analysis, measurements, source material, preservation research, or verified test results become available.

11. User Responsibility

Users are responsible for ensuring that their acquisition, dumping, storage, conversion, use, transfer, or redistribution of ROM images, firmware, game software, security data, and other copyrighted material complies with the laws applicable in their jurisdiction.

Copyright exceptions, archival rights, preservation exceptions, interoperability provisions, private-copying rules, and laws governing technological protection measures differ substantially between jurisdictions.

Accordingly, this project does not represent that possession of original hardware or media automatically grants a legal right to create, download, use, or redistribute a particular ROM image in every jurisdiction.

Nothing in this project constitutes authorization to infringe copyright, violate a software license, distribute proprietary software without permission, or circumvent applicable law.

12. Source Code Distribution and GPL Compliance

Software covered by GPL-2.0 must be distributed in accordance with that license.

Anyone redistributing binaries or FPGA bitstreams generated from GPL-covered source must satisfy the corresponding obligations of the GPL applicable to that method of distribution, including the applicable requirements concerning corresponding source code, copyright notices, license information, and recipients' rights.

Third-party files distributed under compatible licenses remain subject to their own applicable copyright notices, attribution requirements, and license conditions.

Removing an upstream copyright notice, attribution, or license statement from a third-party component does not eliminate the rights or obligations associated with that component.

Consult the project's LICENSE file and individual source-file headers for authoritative licensing information.

13. No Warranty

This software is provided subject to the warranty disclaimer and limitation provisions of its applicable licenses.

Under GPL-2.0, the program is distributed in the hope that it will be useful, but without warranty, including without the implied warranties of merchantability or fitness for a particular purpose, to the extent permitted by applicable law.

The complete and controlling warranty and liability language is contained in the GPL-2.0 license supplied with the project.

Use of experimental FPGA cores, development builds, modified bitstreams, custom timing configurations, unsupported hardware, or other project components is at the user's own risk.

14. Accuracy and Development Status

Compatibility information, hardware descriptions, reverse-engineering findings, game associations, ROM mappings, device descriptions, technical specifications, and implementation details are provided on a best-effort basis.

Namco System 12 existed in multiple board, ROM-board, software, and hardware configurations. A statement applicable to one game, board revision, ROM-board configuration, or software revision should not automatically be assumed to apply to every System 12 implementation.

References to experimental, incomplete, prototype, unreleased, location-test, undumped, partially dumped, or otherwise unavailable software should not be interpreted as confirmation of public availability, preservation status, legal redistribution rights, completeness, FPGA compatibility, or future support.

Information may be corrected or revised as additional evidence becomes available.

15. Legal Notice

This notice is intended to provide transparent attribution and explain the licensing and intellectual-property posture of the project.

It is not legal advice and does not create rights beyond those granted by the applicable software licenses or applicable law.

If you intend to redistribute, commercially distribute, substantially modify, incorporate, or otherwise reuse this project and are uncertain about your obligations, consult the applicable license texts and, where appropriate, qualified legal counsel in your jurisdiction.

No ownership of third-party intellectual property is claimed. Third-party trademarks, copyrighted works, software, and other intellectual property remain subject to the rights and licenses of their respective owners.

Source Code: Github