Re: PC-card - DMA/SBHE

From: Spiro Trikaliotis (Trik-news_at_gmx.de)
Date: 2001-04-17 12:49:27

Hi Ruud,

> A0 = 0 :        D0..7 is written with data from D0..7 of C64
>                 D8..15 is written with invalid data
> A0 = 1 :        D0..7 stays the same
>                 D8..15 is written with data from D0..7 of C64

> I don't think this will cause problems with memory but what about I/O:
could
> any harm be done by writing invalid data to D8..15 the first time? Here I
> merely have the IDE-interface in mind.

Although I don't know an example, I would *highly* assume so (at least in
respect with compatibility with different cards!).

Why don't you just start an 8 bit transfer in this case, so D8...D15 will
not contain any invalid data?

Spiro.

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