DATA PATH CONFIGURATION FOR A DATA PROCESSING SYSTEM

摘要

A data processing system in which the central processor unit operates asynchronously with one or more memory units independently of the operating speed of the memory units wherein the central processor timing signal and the memory timing signal have a predetermined phase relationship. The central processor unit is arranged to remain operative even when the memory unit is enabled unless it is disabled by a signal from the memory unit under preselected conditions. The central processor generates a plurality of operating instruction signals for transfer to the memory unit to permit the latter to perform its desired functions by enabling the memory unit, inhibiting the transfer of data from the memory unit to a data bus and permitting storage of data from the central processor unit when data is acceptable for such storage. A further operating instruction signal is generated at the central processor unit to permit data read from the memory unit to be modified at the central processor unit and stored in the memory unit after such modification. A further operating instruction signal is generated internally to the memory unit to prevent operation of all other memory devices in the memory unit when one of the memory devices therein is in operation.