Arcade-BloodBros_MiSTer

FPGA core for Blood Bros (TAD Corporation, 1990) targeting the MiSTer FPGA platform (Terasic DE10-Nano).

Blood Bros is a shooting gallery game (Cabal-style) running on Seibu hardware (D-Con board family).

Status

Current version: 1.1 (June 2026).

The core runs the full game with audio and inputs.

Features

• M68000 main CPU @ 10 MHz (FX68K cycle-accurate)
• Z80 sound CPU @ 3.579545 MHz (T80s)
• YM3812 OPL2 FM (jtopl2) + OKI M6295 ADPCM (jt6295) with MAME-accurate mixer
• 256×224 active video area
• BG / FG tilemaps (16×16, 4bpp, 32×16 tilemap, shared ROM)
• Text layer (8×8, 4bpp, 32×32 tilemap)
• 16×16 sprites with priority callback (Seibu SEI0210)
• Seibu CRTC registers (scroll, layer enable, flip screen)
• Hardware-accurate DIP switches: Coin Mode, Coinage, Starting Coin, Lives, Bonus Life, Difficulty, Allow Continue, Demo Sounds
• Analog VGA H-Shift / V-Shift OSD options for fine alignment on 15 kHz CRTs
• MiSTer OSD with audio mixer (FM/OKI volume), per-layer debug toggles
• Pause overlay with logo + supporters scroll

ROM sets supported

• Blood Bros (bloodbro, World)
• Blood Bros (bloodbroj, Japan rev A)
• Blood Bros (bloodbroja, Japan)
• Blood Bros (bloodbrou, US — Fabtek license)
• Blood Bros (bloodbrok, Korea)

Screenshots

Title screen	TAD Corporation / Fabtek
Stage select	High scores
Gameplay — river stage	Gameplay — town stage

Hardware emulated

Component	Spec
Master clock	20 MHz crystal (main) + 14.31818 MHz (sound)
Main CPU	M68000 @ 10 MHz
Sound CPU	Z80 @ 3.579545 MHz
Sound chip 1	Yamaha YM3812 OPL2 (jtopl2)
Sound chip 2	OKI M6295 (jt6295) ADPCM, pin7=LOW, 1.32 MHz
Video resolution	256×224 active
Refresh rate	~59.4 Hz
BG layer	16×16 4bpp, 32×16 tilemap, scroll X/Y
FG layer	16×16 4bpp, 32×16 tilemap, scroll X/Y
Text layer	8×8 4bpp, 32×32 tilemap
Sprites	16×16 4bpp, priority (Seibu SEI0210, 512 entries)
Palette	xBGR_555, 2048 entries
Custom video CRTC	Seibu CRTC
Sprite chip	Seibu SEI0210

Hardware requirements

• Terasic DE10-Nano
• MiSTer I/O board (recommended)
• Works on HDMI displays and on 15 kHz CRTs via the analog video output

Building from source

Requires Quartus Prime 17.0 (free Lite Edition).

Open BloodBros.qpf in Quartus → Processing → Start Compilation

Output bitstream is generated in output_files/BloodBros.rbf (~3.5 MB).

Running on MiSTer

The releases/ folder contains the parent MRA and a prebuilt RBF; regional clone MRAs are in releases/alternatives/:

• Blood Bros (World).mra — parent MRA
• BloodBros_YYYYMMDD.rbf — prebuilt bitstream
• alternatives/Blood Bros (Japan rev A).mra / (Japan).mra / (US).mra / (Korea).mra — regional clones

Steps:

1. Copy the .rbf to _Arcade/cores/ on the MiSTer SD card (rename to BloodBros.rbf or keep the dated name and update the MRA accordingly).
2. Copy the .mra file(s) to _Arcade/ on the MiSTer SD card.
3. Provide your legally-owned bloodbro.zip (or regional variant) where the MRA expects it (usually in games/mame/).

ROMs are NOT included in this repository. You must provide them yourself.

Repository layout

Arcade-BloodBros_MiSTer/
├── rtl/
│   ├── BloodBros/    Blood Bros-specific core RTL
│   ├── pll/          Clock PLL
│   ├── sound/        Sound chip cores (jtopl, jt6295, t80)
│   ├── fx68k/        FX68K M68000 cycle-accurate core
│   ├── jtframe/      JTFRAME framework modules
│   └── sdram.sv      SDRAM controller (Sorgelig)
├── sys/              MiSTer framework (Sorgelig / MiSTer-devel)
├── logo/             Pause overlay assets (font, logo, supporter list)
├── docs/             In-game screenshots
├── releases/         Parent MRA + regional clones + prebuilt RBF
├── BloodBros.qpf     Quartus project
├── BloodBros.qsf     Quartus assignments
├── BloodBros.sv      Top-level wrapper
├── Template.sdc      Timing constraints
├── files.qip         HDL file list
├── build_id.v        Build version stamp
└── README.md         This file

Acknowledgements

• Jose Tejada (@jotego) for JTOPL (YM3812), JT6295 (OKI M6295) and the JTFRAME framework.
• Daniel Wallner and MikeJ for the T80 (Z80) core.
• Jorge Cwik (ijor) for the FX68K cycle-accurate M68000 core.
• Sorgelig and the MiSTer-devel team for the framework, SDRAM controller and Template.

Support this project

If you enjoy this core and want to support its development:

• Ko-fi — one-time support
• Patreon — monthly support
• PayPal — one-time donation

Follow

• GitHub
• Twitch — live streams
• YouTube — playlists and videos
• X / Twitter

License

The RTL source code in this repository is provided as-is for educational and preservation purposes under GNU GPL v3 or later. Original ROM data is not included; users must provide their own legally obtained copies.

Original Blood Bros arcade hardware © TAD Corporation, 1990.