Introduction

This device provides a high-speed USB interface between a PC and a SEGA arcade board. I originally developed it so I could rapidly develop and test software on the System 24 platform. Hardware that has a matching expansion connector include:

• SEGA System 16B
• SEGA System 18
• SEGA System 24
• SEGA System 32
• SEGA System C and C-2 (connector is unpopulated)
• SEGA X-Board

Project status

This was the very first electronics project I worked on, and it allowed for experimentation and data logging from the custom Hitachi FD1094 and FD1089 modules. I used the data tables that were extracted to decrypt Tetris, the first non-bootleg FD1094 game to be emulated. Through the hard work of Nicola Salmoria and later Andreas Naive and Aaron Giles, the encryption was figured out and many SEGA arcade games were emulated and preserved forever as a result. Needless to say it is something I am very proud of, even if it is (in retrospect) a simple circuit.

Some hardware such as System 18 and System 32 have poor buffering of the data bus on the I/O connector. I would advise adding 4.7K ohm pull-down resistors on the data bus to help the integrity of these signals which are weakly driven low.

Files

segausb-113008.zip

Project files (PCB layout only)