Re: PC-card - C128

From: Marko Mäkelä (
Date: 2001-05-11 13:21:08

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).


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