slc@hoptoad.uucp (Steve Costa) (05/19/89)
How do the various 68020/68030 boards deal with RAM that is NOT on their 32 bit bus? What happens for instance, if you have 9.5 megs on the 16 bit bus, and add 4 megs onto the co-processor board?
daveh@cbmvax.UUCP (Dave Haynie) (05/23/89)
in article <7369@hoptoad.uucp>, slc@hoptoad.uucp (Steve Costa) says: > How do the various 68020/68030 boards deal with RAM that is NOT on their > 32 bit bus? What happens for instance, if you have 9.5 megs on the 16 bit > bus, and add 4 megs onto the co-processor board? Depends on the board. If the 32 bit memory is autoconfiguring memory, as on the A26x0 boards, it'll configure before any other expansion memory, so some 16 bit expansion memory will be told to shut up. CSA has systems that instead locate 32 bit memory above autoconfig space, and use an AddMem type program to add such memory to the system. In either case, the 32 bit memory is usually the first memory that'll be used by the system, though if it's not autoconfig memory, you'll probably have to set up an appropriate MASK value in the MountList entry for any DMA driven expansion device. -- Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy Amiga -- It's not just a job, it's an obsession