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Hold Request Contention Resolver for Microprocessor System

IP.com Disclosure Number: IPCOM000054275D
Original Publication Date: 1980-Jan-01
Included in the Prior Art Database: 2005-Feb-13

Publishing Venue

IBM

Related People

Authors:
Nay, AH [+details]

Abstract

In the system of Fig. 1, multiple direct memory access (DMA) devices DEV1-DEV4 contend with each other and with microprocessor PROC for access to the address and data lines of ADBUS. These contentions must be resolved by user-supplied logic for microprocessors and DMA devices, such as the Intel 8085 and 8257. RSLV1-RSLV3.1 are identical simple and cascadable circuits to resolve contention for the ADBUS in a first-come, first-served priority.