Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!oliveb!amiga!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga Subject: Re: A2630 questions again Message-ID: <10777@cbmvax.commodore.com> Date: 11 Apr 90 05:05:33 GMT References: <41390@iuvax.cs.indiana.edu> <480@mohawk.cs.utexas.edu> Reply-To: daveh@cbmvax (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 42 In article <480@mohawk.cs.utexas.edu> bryan@cs.utexas.edu writes: > > There seem to be a number of strange phenomena being experienced by >users of the A2630 and older versions of the Microbotics HardFrame. I've just >become one of them. With a new 2630 in my rev4.3 A2000, I get random gurus >(usually #3 or #4) while booting from the HF/Q80S. These gurus occur at random >points in the startup-sequence, so the problem doesn't appear software-related. >After several tries, the machine eventually makes it all the way through the >s-s, after which everything is fine. The 68030 data cache is always off. Older Hardframes have a definite problem with bus arbitration that will only show up with A2620, A2630, GVP, etc. CPU cards with on-board DMA-able memory. They have a fix for this, which is apparently a PAL change. Some DMA controllers on some older A2000s run into a problem with a Signetics 74ALS245 buffer chip at position U605 on the motherboard. The suggested fix for this problem is the addition of a 1K resistor between pins 11 and 20 of U605. This fix is already incorporated into A2000s from Rev 4.5 on up. I don't know how badly the Microbotics board is affected by this problem; it almost certainly is, and almost certainly sees much less of a problem than the A2090. >Does the U5 bus control PAL on the rev4.3 motherboard need to be replaced >as well? There is no U5 bus control PAL. That's only on 4-layer A2000s, the German designed motherboard. All US and most other 2000s are the 2-layer "B"2000 designed in West Chester, the one with Fat Agnus and a megabyte of RAM on the motherboard. > Another question: does anyone have a HardFrame entry for the CardROM >file used by setCPU? I'd appreciate mail on this. You don't need a CardROMFile entry for HardFrame. It uses a byte-wide boot ROM which gets copied into RAM automatically on bootup. -- Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Too much of everything is just enough