PC-card - SBHE-line

From: Ruud Baltissen (Ruud.Baltissen_at_abp.nl)
Date: 2001-04-19 09:07:23

Hallo allemaal,

I'm working on the alpha-version of the document regarding the PC-card now.
As the subject already reveals, one thing is still troubling me: the

This line tell tells the card wether it is an 8-bit or an 16-bit transfer.
When not in DMA-mode, this line is directed by the BHE-output of the
AFAIK the IDE-harddisk only outputs the data as WORDS. The interfaces I know
have no latches. So the only thing I can imagine is that the interface only
only outputs that part accordingly the combination. Consequence is that if
the program asked for only the upper-byte, the next read will the HD make to
output the next word, so overwriting the previous not-read lower-byte. This
would mean that, although in fact the facilities exists, any program MUST
read the data as words to prevent losing data.

I would like some second opinions about this subject. I have thought about
asking this question to a newsgroup but haven't an idea which group to ask.
I'm limited anyway in my choice of groups as the only ones I can access are
only there to the courtesy of the sysops here. So any ideas are welcome.

Groetjes, Ruud


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