Xref: utzoo comp.sys.3b1:482 comp.sys.att:11887 Path: utzoo!mnetor!tmsoft!torsqnt!hybrid!scifi!bywater!uunet!beartrk!ceilidh!dnichols From: dnichols@ceilidh.beartrack.com (DoN Nichols) Newsgroups: comp.sys.3b1,comp.sys.att Subject: Re: 68010 source? Message-ID: <1991Feb23.195504.779@ceilidh.beartrack.com> Date: 23 Feb 91 19:55:04 GMT References: <1991Feb22.063455.436@texrex.uucp> Organization: D and D Data, Vienna, VA. Lines: 47 In article <1991Feb22.063455.436@texrex.uucp> rmfowler%texrex@cirr.com writes: >Where can I get a 68010 and how much would it cost me? I've gotten them from chip dealers at hamfests for about $30.00. There are dealers who sell chips in some of the bigger magazines. Look for multi-page ads. >I just ran diagnostics on the processor and I am getting an error >on the 60 Hz clock test. Maybe THIS is the cause of my crashes. >(But I thought you fixed that by removing your mouse? you say) >Well the mouse must have been a coincidence because the crashes have >resumed. Are you sure that this is testing the cpu CHIP? I think that the 60Hz clock comes from other hardware on the cpu BOARD. The 60Hz clock generates interrupts to the cpu chip, so it could be a problem with the hardware generating the interrupts (perhaps a double interrupt too close together), or a problem in the cpu chip's response to the interrupts. I consider the chip to be unlikely, but it is fairly simple to replace (once you get to it :-). You might look at the interrupt pin in question with an oscilloscope. OOPS! Looking at the tech ref man, the interrupt is encoded into three pins (from seven possible intrrupts). It could be the encoding circuitry that isn't working properly. A glance at the intrrupt lists shows interrupt 6 as being the realtime interrupt. I suspect that this is the one in question. Yes, looking at thr schematics shows the 60Hz interrupt coming into the encoder (IC 18F) at pin 3, which is level 6. It is tied in with the VSync signal for the video, and comes from IC-28H, pin 9. Input is pin 10 (from the Vsync signal), reset at pin 11. The reset comes from IC-27B, pin 12. This is the same chip which drives the leds on the side of the cpu box. Look for a 60Hz pulse present on each of the pins listed. If one of these is missing, this is a clue as to which chips/signals are not working. (But it may be only occasionally missing). > >Thanks You're welcome, and Good Luck DoN. -- Donald Nichols (DoN.) | Voice (Days): (703) 664-1585 D&D Data | Voice (Eves): (703) 938-4564 Disclaimer: from here - None | Email: --- Black Holes are where God is dividing by zero --- Brought to you by Super Global Mega Corp .com