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Catalogue of Arcade Emulation Software - the Absolute Reference

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X-Arcade

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cps3.c

0.81u3 [?]


NOTES:

- Hardware: The CP SYSTEM III comprises a main board with several custom ASICs, custom 72-pin SIMMs for program and graphics storage (the same SIMMs are also used in some CPS2 titles), SCSI CDROM and CDROM disc, and a plug-in security cart containing a boot ROM, an NVRAM and another custom ASIC containing vital decryption information held by a [suicide] battery. Not much is known about the actual CPU used in this system due to the extensive use of encryption, and the volatile nature of the security information, although it is thought to use two Hitachi SH-2 CPUs in a master and slave configuration. A possible theory about how the cart works is that the flashROM in the cart probably contains a program which is executed by the custom Capcom IC inside the cart to boot the game. The code in the flashROM is encrypted, but is likely decrypted using a key probably held in the FM1208S NVRAM. However, if the custom IC detects any tampering (generally things such as voltage fluctuation or voltage dropping), it immediately erases the NVRAM (and thus the key) which effectively kills the security cart dead. It is also possible that the custom Capcom IC may contain some internal code to initiate the boot process which is battery-backed as well. This is all speculation, of course. The main board uses the familiar Capcom SIMM modules to hold the data from the CDROM so that the life of the CD drive is maximized. The SIMMs don't contain RAM, but instead TSOP48 surface mounted flashROMs that can be updated with different games on bootup using a built-in software updating system. The SIMMs that hold the program code are located in positions 1 & 2 and are 64MBit. The SIMMs that hold the graphics are located in positions 3, 4, 5, 6 & 7 and are 128MBit. The data in the SIMMs is not decrypted, it is merely taken directly from the CDROM and shuffled slightly. The SIMMs hold the entire contents of the CDROM. To swap games requires the security cart for the game, it's CDROM disc and the correctly populated type and number of SIMMs on the main board. On first power-up after switching the cart and CD, you're presented with a screen asking if you want to re-program the SIMMs with the new game. Pressing player 1 button 2 cancels it. Pressing player 1 button 1 allows it to proceed whereby you wait about 25 minutes then the game boots up almost immediately. On subsequent power-ups, the game boots immediately. If the CDROM is not present in the drive on a normal bootup, a message tells you to insert the CDROM. Then you press button 1 to continue and the game boots immediately. Note that not all of the SIMMs are populated on the PCB for each game. Some games have more, some less, depending on game requirements, so flash times can vary per game. Due to the built-in upgradability of the hardware, and the higher frame-rates the hardware seems to have, it appears Capcom had big plans for this system and possibly intended to create many games on it, as they did with CPS2. Unfortunately for Capcom, CP SYSTEM III was an absolute flop in the arcades so those plans were cancelled.


WIP:

- 29th March 2006: Razoola - CPS-3 Battery Replacement: Since I get emailed about this alot I have added a short FAQ on how to change batteries on CPS-3 hardware. This is totally based on an older FAQ found on the net and I take no credit for it (http://cps2shock.retrogames.com/cps3/index.html).