CP System III. The  or CPS-3 is an arcade system board that was first used by Capcom in 1996 with the arcade game Red Earth. It was the second successor to the CP System arcade hardware, following the CP System II. The arcade system saw new releases up until mid 1999. Technical support for the CPS-3 ended on February 28, 2019. It would be the last proprietary system board Capcom would produce before moving on to the Dreamcast-based Naomi platform.

Like its forerunners, games can be exchanged without altering the core hardware. This is accomplished on the CPS-3 by providing the necessary CD and game-specific security cartridges, where the contents of the CD are then loaded into memory with the security cartridge decrypting the contents stored within the system memory in run time.

History
The CP System III became the final arcade system board to be designed by Capcom. It features a security mechanism; games are supplied on a CD, which contains the encrypted game contents, and a security cartridge containing the game BIOS and the SH-2 CPU with integrated decryption logic, with the per-game key stored in battery-backed SRAM. Capcom chose the CD medium in order to keep down the price of the system.

In a change from its predecessors, the CP System III consists of a single board instead of two separate boards. The board contains components common to all CP System III games, and includes a slot for the security cartridge. The games themselves are stored on a CD instead of on a separate board, which is then readable by the provided SCSI CD-ROM drive that is connected to the main board. A unique feature of the CP System III is the ability to display games in widescreen, making it the first and only proprietary system board made by Capcom to include this feature. It was only officially used in one game, Street Fighter III: 2nd Impact.

When the CP System III board is first powered on, the contents of the CD are loaded into a bank of Flash ROM SIMMs on the motherboard, where it is executed. The program code is then decrypted at run time via the security cartridge. The security cartridge is sensitive to any sort of tampering, which will result in the decryption key being erased and the cartridge being rendered useless. Games become unplayable when the security cartridge has been tampered with or when the battery inside the security cartridge dies. The lone exception is Street Fighter III: 2nd Impact, which uses a default set of decryption keys that are written to dead cartridges on boot, making it the few, if not the only CPS-3 games prevalent after support was dropped, due to its immunity to cartridge tampering or suicide.

In June 2007, the encryption method was reverse-engineered by Andreas Naive, making emulation possible. Later developments led to the eventual bypassing of the suicide and security routines of the games as well as a development of a so-called "super cartridge" capable of running all CPS-3 games.

Capcom ceased manufacturing the CP System III hardware after 1999. Capcom ended most of the technical support for the hardware and its games on March 31, 2015. Battery replacements ended on February 28, 2019, ending all official support of the CP System III hardware and software.

Specifications
 Main CPU: Hitachi HD6417099 (SH-2) at 25 MHz
 RAM:
 512 KB Work RAM
 512 KB Sprite RAM
 8 MB Character RAM
 256 KB Color RAM
 32 KB SS RAM
 Storage:
 SCSI CD-ROM drive
 Flash ROM: Variable amount, up to 8 × 16 MB
 Sound chip: 16-channel 8-bit sample player, stereo
 Maximum color palette: 16 million shades
 Maximum number of colors on screen: 32,768 (15-bit colour, 555 RGB)
 Palette size: 131,072 pens
 Colors per tile (backgrounds / sprites): 64 (6 bits per pixel) or 256 (8 bits per pixel), selectable
 Colors per tile (text overlay): 16 (4 bits per pixel)
 Maximum number of objects: 1024, with hardware scaling
 Scroll faces: 4 regular + 1 text overlay 'score screen' layer
 Scroll features: Horizontal & vertical scrolling, linescroll, linezoom
 Framebuffer zooming
 Color blending effects
 Hardware RLE decompression of 6 bpp and 8 bpp graphics through DMA
 Resolution, pixels: 384×224 (standard mode) / 496×224 (widescreen mode)

List of games (6 games)
All six games are developed by Capcom and are all head-to-head fighting games.

See also
 CP System
 CP System II

References

External links
 CPS-3 at System16: The Arcade Museum
 CPS-3 memory, suicide and SCSI information
 CPS-1, CPS-2 and CPS-3 releases comparison at UVL

Capcom arcade system boards
SuperH architecture