BUS ACCESS DEVICE, BUS ARBITRATION SYSTEM, CD-ROM DECODER, DVD-ROM DECODER AND CD-ROM DRIVE

摘要

PROBLEM TO BE SOLVED: To provide a bus access arbitration system for a CD-ROM decoder, a DVD-ROM decoder and a CD-ROM drive, etc., which does not fix acquisition conditions of an access right such as a priority and limitation of the number of acquisitions and copes with a variety of uses. ;SOLUTION: This device has plural input-output devices 52 and 53 between which at least one has different bus use rights whose priorities do not continue and which are used for a system that shares a bus, a bus access arbitration circuit 55 which makes the use of a bus use right of input-output controllable whose priority is at least in a higher rank among bus use rights of the input- output device which has different bus use rights whose priority do not continue and a bus access count limitation circuit 51 which limits the access number of the bus access arbitration circuit. For instance, when host CPU transfer takes priority over error correction, it is possible to execute the error correction with high bus use efficiency because the error correction performs read/write by using the access margin time of the host CPU.;COPYRIGHT: (C)1999,JPO