Hallo allemaal, > If the data on the lines does not go back to zero fast enough, > it could appear as refresh data. A normal refresh would NEVER change the data IMHO. If during a refresh CAS is enabled as well, and according the right timing, then it isn't a refresh anymore but a data access. But even that doesn't have to be harmfull as well. A data access can only be destructive if the WE (write) line has been activated as well. And if it is a data access, only one address is involved. Which isn't according the facts :( Hmmm, just struck my mind: during a normal refresh WE is always (H) AFAIK. What happens if WE is accidently enabled during a refresh? Can that be tested in some way? A second thought trail: why $21 and $A1 only ??? The only thing that comes to my mind is that we find port B of the 6525 at address $21 of the I/O part of the 8088. If a write to I/O $21 accidently triggers the RAS line in one or another way, short circuit for example, you have found your trouble shooter. A real refresh would only read port B which wouldn't do any harm and therefore would go unnoticed. The only problem I have with this idea: it would mean an error on the 8088 board and that would mean that the problem should have shown up on the 720 as well. But just in case... -- ___ / __|__ / / |_/ Groetjes, Ruud \ \__|_\ \___| URL: Ruud.C64.org De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd voor de geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u contact op te nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat geval dit e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te maken. Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel ontijdige overbrenging van de inhoud van een verzonden e-mailbericht, noch voor daarbij overgebrachte virussen. APG Algemene Pensioen Groep NV is gevestigd te Heerlen en is ingeschreven in het handelsregister van de Kamer van Koophandel Limburg onder nummer 14099617 The information contained in this e-mail is confidential and may be privileged. It may be read, copied and used only by the intended recipient. If you have received it in error, please contact the sender immediately by return e-mail; please delete in this case the e-mail and do not disclose it's contents to any person. We don't accept liability for any errors, omissions, delays of receipt or viruses in the contents of this message which arise as a result of e-mail transmission. APG Algemene Pensioen Groep NV is registered in the trade register of the Chamber of Commerce Limburg, The Netherlands, registration number: 14099617 Message was sent through the cbm-hackers mailing listReceived on 2011-01-27 07:00:03
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