Nichibutsu M68000 (Terra Cresta) FPGA Implementation

FPGA compatible core of Nichibutsu M68000 (Terra Cresta Based) arcade hardware for MiSTerFPGA written by Darren Olafson. Terra Cresta YM2203 OPN Type PCB donated by @atrac17 / @djhardrich.

The goal for this implementation is gameplay to be 1:1 of the Nichibutsu (Terra Cresta based) 68000 hardware. This core was developed with assistance from atrac17.

Supported Games

Title	Status	Released	Protection	Protected Sets
Terra Cresta	Implemented	Y	None	N/A
Sei Senshi Amatelass	Implemented	Y	NB1412M2	amatelass, amazon
Kid no Hore Hore Daisakusen	Implemented	Y	NB1412M2	horekid

External Modules

Name	Purpose	Author
fx68k	Motorola 68000 CPU	Jorge Cwik
t80	Zilog Z80 CPU	Daniel Wallner
jtopl	Yamaha OPL	Jose Tejada

Known Issues

• Clock domains need to be verified
• H/V clock timing for CRT need to be verified
• Palette issue (wrong colors, stray green/tan lines)
• Sprite flip on boss (right arm)
• Dot Crawl on Y/C video output
• Map Test / Service to keyboard handler
• Service Menu (push button service menu) in Kid no Hore Hore Daisakusen
• Additional debugging features (layer toggle)
• Protection IC NB1412M2 implementation
• Input swap on amatelass, amazon, horekidb
• Sprite / Tile offsets in Kid no Hore Hore Daisakusen (screen transitions)
• Screen Flip implementation
• Sprite Clipping

Remaining Tasks

• Reverse engineer Terra Cresta and provide schematics

PCB Check List

FPGA implementation is based on Terra Cresta and will be verified against the YM2203 PSG Type PCB with a YM3526 swap. Reverse engineering of an authentic Terra Cresta PCB will be done by Darren Olafson; schematics will be included in the repository.

Clock Information

H-Sync	V-Sync	Source
15.625kHz	59.323592Hz	DSLogic +

Crystal Oscillators

Location	Freq (MHz)	Use
2	16.000	M68000
X1	12.000	Z80 / YM3526

Pixel clock: 6.00 MHz

Estimated geometry:

384 pixels/line

263 pixels/line

Main Components

Location	Chip	Use
I C (Top Board)	Motorola 68000 CPU	Main CPU
17 D (Bottom Board)	Zilog Z80 CPU	Sound CPU
20 D (Bottom Board)	Yamaha YM3526	OPL

Nichibutsu Custom Components

Location	Chip	Use	PCB	ROM set
15 G (Top Board)	NB1412M42	Protection IC	Sei Senshi Amatelass Kid no Hore Hore Daisakusen	amatelass, amazon, amazont horekid

PCB Features

Game Debugging
Sei Senshi Amatelass Debugging Features [amatelass, amazon, amazont] Dip switch 7 on bank 1 enables invincibility. When enabled, overclocking the framerate is possible by holding the 2P Start Bttn or enabling turbo in the OSD.
Kid no Hore Hore Daisakusen Debugging Features [horekid, horekidb1, horekidb2] Debug Mode and cabinet Upright dip switches are set to default. When enabled, you will be able to access the following debug features: Level Selection: insert a coin and press P2 Bttn 1 and 2. In the bottom right corner, 00 will be displayed. Pressing P2 Bttn 1 and 2 and P1 1 Bttn 1 increases the level. Pressing P2 Bttn 1 and 2 and P1 Bttn 2 decreases the level. Press P1 start after choosing your level selection. Invincibility and Infinite Time are set by inserting a coin and pressing P2 Bttn 1, P2 Bttn 2 and P1 Start Bttn. To enable the debug level select, set your level prior to enabling these debug features.

GFX Layer Toggle

• The three graphical layers can be toggled in the OSD under the Debug options or by pressing
  F7-F9 on the keyboard.

Layer Debug
All Layers Foreground Background Sprites

Sprite Flip on Axis Toggle

• To enable sprite flip, in the OSD under the Debug options enable
  the toggle.

Sprite Flip
All Layers Sprite Flip X-Axis Sprite Flip Y-Axis

Control Layout

Game	Joystick	Service Menu	Shared Controls	Dip Default
Terra Cresta	8-Way		Upright	Table
Sei Senshi Amatelass	8-Way		Upright	Table
Kid no Hore Hore Daisakusen	4-Way		No	Upright

• Upright cabinet shares a 1L2B control panel layout. Players are required to switch controller. The default cabinet style is set to table for Terra Cresta and Sei Senshi Amatelass. This enables multiple player controllers.

Keyboard Handler

• Keyboard inputs mapped to mame defaults for all functions with additional keys for layer toggles.

Services	Coin/Start
Functions Keymap Test F2 Reset F3 Service 9 Pause P	Functions Keymap P1 Start 1 P2 Start 2 P1 Coin 5 P2 Coin 6

Player 1	Player 2
Functions Keymap P1 Up Up P1 Down Down P1 Left Left P1 Right Right P1 Bttn 1 L-Ctrl P1 Bttn 2 L-Alt	Functions Keymap P2 Up R P2 Down F P2 Left D P2 Right G P2 Bttn 1 A P2 Bttn 2 S

Debug
Functions Keymap Layer (FG) F7 Layer (BG) F8 Layer (SP) F9

Support

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

Licensing

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