Path: utzoo!mnetor!uunet!oddjob!ncar!ames!smyoung From: smyoung@ames.arpa (Sarah M. Young) Newsgroups: comp.sys.m68k Subject: emulating 68000s: Force * HP = aargh Message-ID: <6655@ames.arpa> Date: 30 Mar 88 03:29:53 GMT Reply-To: smyoung@ames.arc.nasa.gov.UUCP (John Graybeal) Distribution: comp.sys.m68k Organization: NASA Ames Research Center, Moffett Field, Calif. Lines: 22 Keywords: 68000, emulation My group is having an emulation problem maybe someone else has seen. We're trying to emulate a 68000 chip with an HP64000 68000 emulation pod and system. The chip is on a Force CPU-5 board. Whenever we try to access off-board memory (this is VME bus, by the way), sooner or later (usually within a minute or two) we get bus errors. Amazingly enough, some tests have indicated the problem to be data-dependent, with writing 'FF's working quite well while writing '00's failing almost immediately. We have not had this problem with: any other Force or Plessey board, llike CPU 2B or CPU 3; another emulator used with the Force CPU 5 board (a MICE emulator). Force says they've never seen this problem with any other emulators, and HP says they've never seen this problem with any other boards. They both agree that it should work, and that we don't seem to be doing anything wrong that would keep it from working (and that it doesn't work). Predictably, this isn't the biggest problem either company has ever had, so can someone out there provide any clues? (We've heard rumors of one or two other groups having this problem; can anyone confirm or deny? We'd love names.) Of course, I'm using 'we' advisedly, because I'm not speaking for -- well, You know. John Graybeal