OutRunners hits MiSTer FPGA with full two player split screen support

Sega’s OutRunners has made its way to MiSTer FPGA with a dedicated core built around the arcade game’s original Multi 32 hardware. That’s a fairly serious job. OutRunners wasn’t designed as a simple single-screen racer, and its hardware setup reflects that. The new core supports the World, US and Japanese versions of the game, along with local two-player split-screen on one display. So you don’t need the sort of twin-monitor arcade setup that Sega originally had in mind. Both players can race side by side on a modern screen, while the FPGA handles the game’s unusually complicated video and audio setup underneath.

Sega Multi 32 pushed hard

OutRunners runs on Sega’s Multi 32 arcade hardware, which was built to handle two displays at once. That immediately makes it more demanding than many earlier Sega arcade boards. The MiSTer implementation has to reproduce both video paths, the sprite system, scrolling backgrounds, analogue driving controls and the game’s sound hardware. It also has to fit all of that into the DE10-Nano FPGA. There isn’t much room left.

The current build uses roughly 98 per cent of the available FPGA logic and around 99 per cent of its internal memory. It also requires the 128 MB SDRAM expansion normally used with more demanding MiSTer cores.

That tells you a lot about the job involved. This isn’t simply a matter of loading a ROM and mapping a few controls. Multi 32 expects a lot of hardware to exist at the same time, and OutRunners makes good use of it.

Two players, one display

The split-screen option is probably the feature most people will notice first. In the arcade, OutRunners could run across two screens, giving each player a separate view. Linked cabinets could take the idea even further. On MiSTer, the new core can combine both views onto a single monitor instead. It’s a practical solution, and it suits the way most people use MiSTer hardware at home.

The core also includes several display options, including the original 4:3 presentation, full-screen output, integer scaling and MiSTer’s usual CRT-style video filters. Driving controls are well covered too. You can use an analogue wheel, analogue stick, paddle or relative spinner-style input for steering. Acceleration and braking can run through analogue axes or ordinary digital controls, depending on the hardware you’ve got connected. EEPROM support is included as well, so settings and high-score data don’t disappear every time you switch the system off.

It’s not claiming perfect hardware accuracy

The developers aren’t presenting the core as a completely cycle-accurate copy of every part of the original arcade board. Some timing behaviour, analogue details, protection logic and programmable hardware still have areas that aren’t fully understood or reproduced.

That said, the main OutRunners hardware is represented. The implementation covers the V70-compatible CPU side, tilemaps, sprite hardware, dual video output, analogue controls, Z80-based sound processing, Yamaha FM audio and Sega’s MultiPCM sample system. For a game this complex, that’s a substantial amount of hardware to fit into one FPGA build.

OutRunners was Sega at full speed

OutRunners arrived in arcades in 1993 and followed the basic formula of the original OutRun while making almost everything bigger. You still race through branching routes, choosing your direction at junctions, but this time there are more cars, more stages and a much stronger multiplayer focus.

Players can choose from eight vehicles with different handling characteristics. Some favour speed, while others lean towards acceleration or grip. The game offers 30 stages across eastbound and westbound routes, with several possible destinations depending on the path you take.

Multiplayer was a major part of the arcade design. Sega could link multiple cabinets together, allowing up to eight people to race at once. The driver in front decided which route the group followed when the road split. That could make races unpredictable very quickly.

A late showcase for Sega’s sprite hardware

OutRunners came from a period when Sega was starting to move towards polygon-based arcade systems, but its sprite-scaling hardware was still doing a lot of heavy lifting. Multi 32 used a 32-bit NEC V70 processor and could push large sprites, layered backgrounds and scaling effects across multiple displays. OutRunners takes advantage of that throughout the game, especially when the road gets busy or the scenery starts flying past at speed.

A Mega Drive version followed in 1994, but the home conversion had to work within much tighter limits. It used a permanent split-screen setup and naturally cut back the graphics and presentation. The arcade version is the one this MiSTer core targets.

A very specific MiSTer core

This isn’t a general Sega Multi 32 core designed to run everything on the board. It’s focused on OutRunners. That narrow approach makes sense here. The game uses enough of the hardware to push the DE10-Nano close to its limits already.

What you get is a MiSTer version built around the structure of the original 1993 arcade release, including the dual-screen system that shaped its multiplayer design. Add analogue control support, regional ROM compatibility and single-monitor split-screen, and it becomes a fairly complete way to run one of Sega’s more complicated racing games on FPGA hardware.

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