Hiya Joseph, --- On Wed, 21/3/12, Joseph Rose <rose.joseph12@yahoo.com> wrote: From: Joseph Rose <rose.joseph12@yahoo.com> Subject: [cc65] c64 cartridge types? To: "cc65 mailing list" <cc65@musoftware.de> Date: Wednesday, 21 March, 2012, 4:45 PM > Hi. I have two queries: 1. I am missing some information on some C64 > cartridge types. I am interested in the Action Replay and Atomic Power > cartridges. What's so special about the Final Cartridge I, Rex Utility, > Westermann Learning, Epyx Fastload and other 8k and one-bank 16k > cartridges? 2. In the Magic Desk format, is $A000-$BFFF BASIC ROM or RAM? The thing that makes the 8kb/16kb 1 bank cart types special is mostly the way that they get switched off (and sometimes back on) and if parts of the rom are mirrored in the I/O areas. Most of the details of this are in the CRT.txt document: FC1 --- Any access to I/O-1 turns cartridge ROM off. Any access to I/O-2 turns cartridge ROM on. The cart ROM is visible in I/O-1 and I/O-2. REX UTIL -------- Reading from $DF00-DFBF disables ROM, reading from $DFC0-DFFF enables ROM (8k game config). WESTERMANN ---------- Any read from the I/O-2 range will switch the cart off. EPYX ---- The Epyx FastLoad cart uses a simple capacitor to toggle the ROM on and off: The capacitor is discharged, and 8k game config enabled, by either reading ROML or reading I/O-1. If none of those accesses happen the capacitor will charge, and if it is charged (after 512 cycles) then the ROM will get disabled. Hope this helps a bit. Signed, Marco van den Heuvel. ---------------------------------------------------------------------- To unsubscribe from the list send mail to majordomo@musoftware.de with the string "unsubscribe cc65" in the body(!) of the mail.Received on Wed Mar 21 16:52:52 2012
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