Here’s an informative part 2 of the Capcom CPS2 reverse engineering series by Eduardo Cruz:
Capcom’s Play System 2, also known as CPS2, was a new arcade platform introduced in 1993 and a firm call on bootlegging. Featuring similar but improved specs to its predecessor CPS1, the system introduced a new security architecture that gave Capcom for the first time a piracy-free platform. A fact that remained true for its main commercial lifespan and that even prevented projects like Mame from gaining proper emulation of the system for years.
from Dangerous Prototypes http://ift.tt/2rgoU5o