Date: 2008-09-17 11:38:25
Hallo allemaal, This morning I had a weird idea: replace the 6510 by a 6809. Using Eagle I checked if replacing the 6510 was possible and I found no problem. But checking the data sheets I saw that the 6809 needs a crystal or external clock four times the bus clock. OK, end of idea I thought. But then I got the idea to have a look at the schematics of the SuperPET. My very first thought was that the SP has a 16 MHz clock on the board and it is easy to derive 1 MHz from it. But then I remembered that the 6809 board is connected with the 8032 board through the socket of the 6502. And here is no 16 Mhz available (I thought, but checking the SCH of the all-in board I saw that 16 MHz is provided through the flatcable but isn't used as so). What completely baffled me was the fact that the outputs Q and E are forced to become inputs and fed with a signal derived from CLK0. So IMHO theoretically one could use the circuit from the first 6809 board (324037-1.gif) to replace the 6510 with the 6809. Some questions: - did anyone notice this, IMHO weird, use of the Q and E outputs before? - how is this possible, I mean, two outputs connected together? - are there 6809 experts amongst us? - beside the well known "because it can be done", is there another reason we benefit from a 6809 in a C64? (I was thinking about the FLEX OS) -- ___ / __|__ / / |_/ 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 list
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