On Fri, 11 May 2001, Ruud Baltissen wrote: > But I must admit that I'm not familiar with the C128-mode of the C128, > particular the behaviour of some lines of the expansion slot (EXROM and GAME > can become outputs IIRC?). So I would like to ask: > - which ranges are free at 2 MHz? Yes, EXROM and GAME are bidirectional in the C128 mode. I think that the most practical use for them would be additional bank switching lines (outputs from C128 to the cartridge). As far as I know, in its 2 MHz mode, the VIC-IIe slows down to 1 MHz only during memory refreshes and when the IOACC signal is active. This signal should only be active when accessing the I/O space ($d000-$dfff). > - (how) are they accessible using a cartridge? I'm not sure, but I think ROML and ROMH are the enable signals for cartridge-based memory. The memory mapping is selected with the MMU using $d500 or $ff00 (or the memory configuration preset registers $d501-$d504 and the "load memory configuration" registers $ff00-$ff04). Marko - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail email@example.com.
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