From: Baltissen, R (Ruud) (ruud.baltissen_at_abp.nl)
Date: 2003-08-19 15:49:08
Hallo Oliver, > Actually, the original 64er 2Mhz accelerator would also need a > 4Mhz part since the designer stuffs 2 cycles into one time-window. No, 3 MHz. Find out yourself why :) > > Remark for Oliver: when using the 65816, what about using its 16 MB > > capabilities? Can provide you with quite some nice ideas. > > I´m eager to hear them... :-) The start is quite simple: - you need a 74LS245 as buffer between the data lines of the C64 and 65816 - you need a 74LS541 to buffer the addresses A11..A15 and the R/W line between the C64 and 65816 - you need pull-up resistors for the addressbus and R/W line - you need a 74ALS573 to generate A16..23. - you need a 74LS688 to find out if the firts 64 KB are addressed or not. - you need some small glue logic When data is read or written to the first 64 KB area, the original C64 parts are addressed. If not, the 688 will disable the 245 and the 541 which causes the C64 to think that data is read from the $Fxxx area. Now you are free to use the complete 16 MB :) > No need to do that. With the fast SRAM replacing the old > DRAMs, everything (except register writes) can run at full speed. Don't forget the ROMs. (but you mentioned using the 29F010) > Why slow-down writes when the Drams are replaced anyway? Only > access to the colour ram has to be slowed down. Why not replace it as well? You mention the use of 8 virtual C64s. Then this also meeans the need of 8 color RAMs. Other wise you will face the problem that as soon as one virtual C64 changes the backgroundcolors, this action will affect ALL C64s. -- ___ / __|__ / / |_/ Groetjes, Ruud \ \__|_\ \___| http://Ruud.C64.org =====DISCLAIMER================================================================= 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. 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 its 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. Message was sent through the cbm-hackers mailing list
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