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Nichibutsu M68000 (Armed F) FPGA Implementation

FPGA compatible core of Nichibutsu M68000 (Terra Force Based) arcade hardware for MiSTerFPGA written by Darren Olafson. Terra Force PCB (different board revisions) donated by @atrac17 / @djhardrich.

The intent is for this core to be a 1:1 implementation of the Nichibutsu (Terra Force based) 68000 hardware. Currently in an beta state, this core is in active development with assistance from atrac17.

Supported Games

Title Status Released Protection Unprotected Sets
Terra Force Implemented terraf, terrfj, terrafu NB1414M4 terrafjb, terrafb
Kozure Ōkami Implemented kozure NB1414M4 N/A
Chouji Meikyuu Legion Implemented legion, legionj2 NB1414M4 legionjb, legionjb2
Crazy Climber 2 Implemented cclimbr2, cclimbr2a NB1414M4 N/A
Armed F Implemented armedf, armedff None N/A
Tatakae! Big Fighter Implemented skyrobo, bigfghtr i8751 N/A

External Modules

Name Purpose Author
fx68k Motorola 68000 CPU Jorge Cwik
t80 Zilog Z80 CPU Daniel Wallner
jtopl2 Yamaha OPL 2 Jose Tejada
jt8751 Intel 8751 Oregano Systems / Jose Tejada
yc_out Y/C Video Module Mike Simone

Known Issues / Tasks

  • Screen Flip implementation
  • Layer priority - Chouji Meikyuu Legion (Japan ver 1.05) [legionj, legionjb]
  • Service Menu text layer NB1414M4

PCB Check List

FPGA implementation is based on Terra Force and verified against an authentic Nichibutsu U.S.A Terra Force PCB and bootleg PCB.

Reverse engineering of an authentic Terra Force PCB will be done by Darren Olafson and schematics will be included in the repository.

Clock Information

H-Sync V-Sync Source
15.51kHz 59.092993Hz DSLogic +

Crystal Oscillators

Location Freq (MHz) Use
C1 (Top Board) 16.000 M68000
F1 (Bottom Board) 24.000 Z80 / YM3812

Pixel clock: 6.00 MHz

Estimated geometry:

(Terra Force, Kozure Ōkami, Armed F, Tatakae! Big Fighter)

387 pixels/line

262 pixels/line

(Chouji Meikyuu Legion, Crazy Climber 2)

352 pixels/line

248 pixels/line

Main Components

Location Chip Use
D1 (Top Board) Motorola 68000 CPU Main CPU
H17 (Bottom Board) Zilog Z80 CPU Sound CPU
K15 (Bottom Board) Yamaha YM3812 OPL2
D1 (Daughter Board) Intel 8751 Protection MCU (Tatakae! Big Fighter)

Nichibutsu Custom Components

Location Chip Use PCB ROM set
A9 (Top Board) NB1414M4 Protection IC Chouji Meikyuu Legion

Terra Force

Kozure Ōkami

Crazy Climber 2
legion, legionj, legionj2

terraf, terrafu, terrafj


cclimbr2, cclimbr2a

PCB Features

Debugging Menu

A hidden debug menu can be accessed for all Nichibutsu 68000 (Armed F Based) titles. For more information on each debugging menu per game click here.

Each debug menu has different features to display Character, Object, Scoll, Foreground, Background, Stage Viewer, or Priority tests.

Follow these steps to access the debug menu (OSD or Keyboard):

  • Turn on Service Menu in the debug OSD options or press F2. Then turn on Debug Menu or press and hold R, A, S. For Crazy Climber 2 press and hold Up, LCtrl, Spacebar.

  • Toggle the Service Menu option off; then toggle Debug Menu off in the OSD or keep those corresponding keys held and press F2.

    Note: Crazy Climber 2 is not accessible in the OSD.

Character Graphics ROMObject Graphics ROMBasic Stage ViewerSprite Priority Test

Debugging Features

Chouji Meikyuu Legion Debugging Features [legion, legionj, legionjb]

Chouji Meikyuu Legion has hidden debug dipswitches by enabling offsets at
0x000488 and 0x0001d6. Bank 1, switch 8 enables these options on bank 2,
switch 7 and 8.

This enables P1 and P2 Invunerability and the ability to overclock the games
framerate by holding the 2P Start Bttn.

The dipswitch information was taken from mame, the overclocked framerate
was discovered during core development.

These features are enabled in the MRA's for the corresponding sets.

Tatakae! Big FighterDebugging Features [skyrobo, bigfghtr]

There are two dipswitches labeled unused in the in the Tatakae! Big Fighter manual.

The dipswitch location for bank 2, switch 6 enables invulnerability and the ability to
skip the level by pressing P2 Start Bttn.

The dipswitch location on bank 2, switch 8 enables pause in game, this was used for
development debugging.

Core Features

Native Y/C Output

H/V Adjustments

  • There are two H/V toggles, H/V-sync positioning adjust and H/V-sync width adjust. Positioning will move the display for centering on CRT display. The sync width adjust can be used to for sync issues (rolling) without modifying the video timings.

Scandoubler Options

  • Additional toggle to enable the scandoubler without changing ini settings and new scanline option for 100% is available, this draws a black line every other frame. Below is an example.
Scandoubler FxScanlines 25%Scanlines 50%Scanlines 75%Scanlines 100%

GFX Layer Toggle

  • The four graphical layers can be toggled in the OSD under the Debug options or by pressing F7-F10 on the keyboard.
Text LayerBackground LayerForeground LayerSprite LayerAll Layers


GameJoystickService MenuShared ControlsDip Default

Armed F




Chouji Meikyuu Legion




Crazy Climber 2




Kozure Ōkami




Terra Force




Tatakae! Big Fighter




Note: (Only applies once screen flip is implemented)

Upright cabinets share a 1L3B control panel layout. Players are required to switch controller. If set the cabinet type is set to table, the screen inverts for cocktail mode per player and has multiple controls.

Push button 3 may have no function in game, but corresponds to the original hardware and service menu. Crazy Climber 2 uses two 4-way joysticks and the second stick (right) corresponds to buttons 1 thru 4 for movement.

Keyboard Handler

  • Keyboard inputs mapped to mame defaults for all functions.

Services Coin/Start
P1 Start1
P2 Start2
P1 Coin5
P2 Coin6
Player 1 Player 2
P1 UpUp
P1 DownDown
P1 LeftLeft
P1 RightRight
P1 Bttn 1L-Ctrl
P1 Bttn 2L-Alt
P1 Bttn 3Space
P1 Bttn 4L-Shift
P2 UpR
P2 DownF
P2 LeftD
P2 RightG
P2 Bttn 1A
P2 Bttn 2S
P2 Bttn 3Q
P2 Bttn 4W
Layer (TXT)F7
Layer (FG)F8
Layer (BG)F9
Layer (SP)F10


Please consider showing support for this and future projects via Darren's Ko-fi and atrac17's Patreon. While it isn't necessary, it's greatly appreciated.


Contact the author for special licensing needs. Otherwise follow the GPLv2 license attached.


Nichibutsu Armed F / Terra Force WIP







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