🐸Battletoads🐸 - It's Stompin Time!

Please watch the video above for details

⚡ tl;dr

• 📦 Loads from the standard MAME ROM

• 🎮 3-player support, named controls, all 8 DIP switches
  To be able to choose which character you want to play as, disable "3 Player" in dip switch settings.

• 🔊 True stereo sound

• 💾 High scores are saved

• ⏸️ Optional OSD Pause

• 🖥️ More scaling modes, scanlines and CRT Adjust settings

• 🎮DIP switch settings

• 📺 Native 15.6 kHz / 60.8 Hz raster

• 🐛 Player-under-enemies sprite bugs fixed

• 🐛 Cut-off HUD icons and static screens fixed

• 🐛 HDMI sync dropouts fixed

Credit first

srg320 wrote the original core in April 2023: the TMS34020 graphics CPU, the blitter and the BSMT2000 sound. Everything below is built on that work.

The original was a proof of concept. It needed a hand-made ROM setup, had no real platform features, and didn’t fit comfortably on the FPGA.

🎮 Loads and plays like a proper arcade core

• Standard MRA and MAME ROMs. Runs on the unmodified MAME 0.289 btoads.zip. No extracted ROM files and no extra ZIPs.

• Safe loading. Both CPUs are held in reset until the whole 8 MiB program, samples and Z80 code are written. I checked every payload byte against an independent MAME layout.

• Controls named for what they do: Attack, Jump, Coin, Start, Service Menu, Pause. Players 2 and 3 were fixed, and all three players can use service and pause.

• All eight DIP switches are in the OSD, including Three Players (on by default) and Free Play.

• True stereo by default. MAME’s “Stereo” DIP label has its polarity reversed, which makes its default sound near-mono. The core’s default gives real stereo.

💾 High scores that stick

• The cabinet’s 8 KB NVRAM now saves and restores, so high scores and service settings survive.

• It auto-saves when you open the OSD after a change. The CPU pauses for the save and the video keeps running.

• OSD Pause (optional, off by default) halts the game while the menu is open.

🖥️ Video options

• Scaling modes: V-Integer and HV-Integer variants.

• 2x line doubling and CRT scanline effects.

• CRT Adjust for analog and direct video: H-size, H-position and V-shift.

• A steady 10 MHz pixel clock gives 15.625 kHz × 60.8 Hz native timing, a 640×257 raster.

🐛 Real bugs found and fixed

• Player drawn under enemies. The TMS34020’s “find rightmost one” instruction returned the wrong bit number, which silently switched off the game’s sprite depth-sorting.

• Cut-off HUD icons and static screens. The per-frame clear of the foreground page was too slow and the page flip landed after the picture had started. Writing it in 64-bit bursts brings the flip back into vertical blank.

• Lost display sync. At boot the game clears the display-enable bit mid-frame, and the old core stopped all sync output. That is why the HDMI scaler dropped the signal.

⚙️ Making it fit and run fast

• Memory. RAM-block use went from 541 to about 86% of the chip, which was over the safe limit.

• Timing closure. The core runs at 80 MHz system and 160 MHz memory clocks, and the chip’s timing checks now all pass. That took a lot of restructuring of the CPU and foreground-graphics paths, then sweeps over many placement seeds, weeks of work. The release RBF is checked at all four timing corners with zero unconstrained paths.

• Cleanup. The framework is updated to the current mister framework Template, with CPU sources bundled into the project.

Gameplay from boot

👾Join the Slop Goblins in the Slop Hub on Discord!

How to install

Get downloader_meatcores.ini below and place it in your mister SD card root folder, right next to downloader.ini

Run Update_All then load the games from Arcade/Meatcores

To update Meatcores and get any new games just run Update_All again

If you have downloader_meatcores.ini already just run Update_All then load the games from Arcade/Meatcores