rpa@raven.ukc.ac.uk (R.P.Almeida) (07/25/88)
Ive just had the Motherboard in my Amiga 2000 replaced, and found that a 4.4 Motherboard has been installed. Could someone at CATS tell me ehat the changes between 4.3 and 4.4 are ? Also could someone tell me which link causes the 0x00C00000 memory to be mapped at 0x00080000 ? I know this information would be in the A500/2000 tech ref manual, but I'm about to order one, but as i'm in the UK, it will probably take a long time to arrive. I also have the memory expansion board from an A2000 (the original Amiga2000) populated to 1Mbyte. I wanted to install it in the B2000, so i disconnected link J500 on the B2000 , so as to disable the 0x00C00000 memory totally, and installed the board. It didnt work. This worries me, are the A2000 and B2000 CPU slot timings that different? Thank you Richard Almeida rpa@uk.ac.ukc !mcvax!ukc!rpa rpa@ukc.UUCP
daveh@cbmvax.UUCP (Dave Haynie) (07/27/88)
in article <826@raven.ukc.ac.uk>, rpa@raven.ukc.ac.uk (R.P.Almeida) says: > > Could someone at CATS tell me ehat the changes between 4.3 and 4.4 are ? How about someone in Systems Design? The R4.4 board has two resistors on the board layout that had to be added by hand on the R4.3 board. It also has a few traces and things moved around, to make it easier to produce than a R4.3 board. > Also could someone tell me which link causes the 0x00C00000 memory to be > mapped at 0x00080000 ? That's the link marked J101. But DON'T move this jumper until you get a 1 meg Fat Agnus installed, or the system will die miserably as soon as any of that remapped-into-chipram-space-but-not-really-chip-accessable memory gets touched. > I also have the memory expansion board from an A2000 (the original Amiga2000) > populated to 1Mbyte. Remove the memory chips and throw it away! > I wanted to install it in the B2000, so i disconnected link J500 on the B2000 > , so as to disable the 0x00C00000 memory totally, and installed the board. > It didnt work. No, it wouldn't. > This worries me, are the A2000 and B2000 CPU slot timings that different? There are some slight differences, both in timing (mainly the difference between Thin and Fat Agnus) and in signals on the CPU slots (due to the B2000's full CPU slot implementation). This isn't a problem is you design things to the published specs. The A2000's add-on board wasn't designed to our specifications, it was designed specifically for the A2000, using unpublished information about the A2000 that doesn't necessarily apply to any other Amiga. It should only be used in an A2000. > Thank you > Richard Almeida -- Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests" {ihnp4|uunet|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy "I can't relax, 'cause I'm a Boinger!"