This is one of the biggest challenges we face as C-64 users. The C-64 is not a card-cage design, its a semi-closed architecture. This is one area the Apple II line has a great advantage in. Firstly the cart port is not electronically suited to cart chaining due to excessive signal degredation (so I understand), so plugging more than one cart into a cart port expander is a hit/miss deal. It either works, or doesn't, or only works if its close enough to the motherboard (this I know from experience.) If a new C-64 motherboard design is in the future, I hope it makes some allowance for real expansion slots. Second problem, there is no defined convention for how the extra I/O space (the mirror registers) are to be divvyed up to hardware expansion devices. Most designers just seem to grab whatever's convenient, as did Commodore with the C-128 MMU, 1750 REU and VDC. It would be really cool if someone had a list of every device that uses I/O space and where it is situated for the purpose of avoiding confilicts in future designs. --- email@example.com wrote: > There would be a control unit at an as-yet undefined > location, > preferrably one located in one of the I/O pages. > This unit has the > following functions (some optional, for later > post-proof-of-concept > implementation): > > The addressing spaces (memory OR io) can be mapped > in 256 bytes at a time > into one of the I/O pages. My design assumes its > the first non-cpu device > on the cartport chain, so enabling this map will > override whatever page you ===== Get a FREE 6Mb webmail box from go6502! - http://www.geocities.com/profdredd As low as 2.99% Intro APR from NextCard! - http://www.nextcard.com/index6.html?ref=aff0074521 PayPal is the FAST FREE and SECURE way to send money! - https://secure.paypal.x.com/refer/pal=profdredd%40yahoo.com __________________________________________________ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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