Namco System 12 MiSTer core expands with Tekken Tag Tournament and six new games

The Namco System 12 core for MiSTer FPGA has taken a sizeable step forward with Beta 3. Tekken Tag Tournament is the big addition, but there’s a lot more going on here than one new game. The update also adds Aqua Rush, the Japanese version of Mr. Driller and all three Paca Paca Passion titles. That brings the core to 14 supported games and 36 different versions. Just as importantly, Beta 3 changes how the core handles later System 12 hardware, including protection, ROM loading, memory use, sound and physical controllers. Some of those changes were needed simply to get Tekken Tag Tournament running properly.

Tekken Tag Tournament needed more than a compatibility patch

Tekken Tag Tournament uses a different hardware setup from some of the earlier System 12 games. Its M8F4 ROM board includes extra programmable logic alongside Namco’s KC044 KEYCUS security chip. That matters.

The game sends 64-bit challenges to the protection hardware and expects specific replies. Protection also affects the ROM DMA system, so getting the game to boot isn’t just a case of loading the ROMs and hoping for the best. Beta 3 now recreates that behaviour inside the FPGA core.

There’s also an unusual boot detail. Tekken Tag Tournament looks for a 12-byte Namco signature at a fixed memory location. The problem is that the startup process clears that area and later uses it for game code. The core has to handle the timing carefully. It keeps the signature available long enough for the boot ROM to find it, then gets out of the way before the game writes over the same memory.

The game also pushes MiSTer’s memory harder

Tekken Tag Tournament carries a 56 MB banked game ROM region. That’s twice the size used by Tekken 3. This creates a practical memory problem because the larger ROM area overlaps space that had previously been used for sound data. Beta 3 works around that by moving the audio engine and wave ROM to MiSTer’s second SDRAM device.

There is a catch. Tekken Tag Tournament now needs a 128 MB SDRAM module. That requirement won’t affect every game in the core, but it’s something anyone specifically interested in Tekken Tag Tournament will need to check before loading it.

ROM loading gets a rethink

Getting Tekken Tag Tournament to boot wasn’t the end of the job. The game could still report corrupted ROM data. The issue came from the way its files were being loaded. The original setup used 32-bit word-interleaved ROM maps, which could leave part of the data incomplete. Beta 3 switches to byte-interleaved loading and then rearranges the data internally.

It sounds like a small change. It isn’t. This gives the core a cleaner and more consistent way of dealing with the ROM layouts used across the supported System 12 library. Beta 3 also fixes an EEPROM issue that could leave Aqua Rush hanging on its first boot.

Audio and video controls get useful changes

Sound receives attention across the entire core. A problem with the C352 audio latch could introduce unwanted static in System 12 games, and Beta 3 includes a fix for it. The Video & Audio menu is back too.

That means users once again have access to settings for aspect ratio, scaling, deinterlacing and stereo mixing. These aren’t headline features, but they matter when you’re trying to match the output to a particular monitor or setup.

CRT users get an extra set of controls. Horizontal size, horizontal position and vertical shift can now be adjusted through MiSTer’s on-screen display while the monitor stays synchronised. In practical terms, you can tweak the picture without repeatedly reaching for the controls on the CRT itself. The option stays disabled by default, and HDMI output works as before if you leave it alone.

DB9 and DB15 controllers now work directly

Beta 3 also expands native user-port controller support. Mega Drive and Genesis three-button and six-button pads are supported, along with Neo Geo and Supergun-style DB15 arcade sticks. A compatible splitter can handle two players.

These controllers work during gameplay with standard MiSTer firmware. If you want to control MiSTer menus directly from DB9 hardware, you’ll still need the MiSTer-DB9 software fork. It’s a fairly specific feature, but one that makes sense for arcade-focused setups using original-style controls.

A few limitations remain

This is still beta software, and not every System 12 issue has been solved. Soul Calibur can produce a small amount of static in its music, and the audio can sound slightly thinner than expected. Gameplay and sound effects continue to work.

The US version of Mr. Driller isn’t included yet because of intermittent screen flashing, although the Japanese version is available. Oh! Bakyuuun reaches attract mode, but light-gun aiming hasn’t been implemented. So Beta 3 isn’t the finish line.

What it does provide is a much broader Namco System 12 implementation. Support now covers more games, more ROM configurations and more hardware setups, while Tekken Tag Tournament has forced several parts of the core to become more flexible. That makes this update less about adding one famous fighting game and more about expanding what the System 12 core can actually handle.

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