INTERFACING DEVICE FOR COMPUTER GAME SYSTEM

摘要

INTERFACING DEVICE FOR A COMPUTER GAME SYSTEM An interfacing device for connecting the processing unit of a computer game system to an external data storage medium, has an address comparison unit for comparing addresses from the processing unit with a reference address Aref and causes replacement data Drep to be substituted for data in the addressed storage location of the external data storage medium whenever the compared addresses are the same. Control circuitry is used to monitor addresses from the processing unit to detect for self-checking activity and inhibits the substitution of data if self-checking activity is detected. Data from the external data storage medium may be compared with reference data, and data replacement may be inhibited during a current read access cycle in response to data comparison carried out selectively during the current read access cycle or during a read access cycle earlier than the current read access cycle.