8-bit IDE

From: allisonp <allisonp_at_world.std.com>
Date: Mon Apr 17 16:48:30 2000

>I seem to remember that the IDE standard that I read said that the
>command/status registers were all 8 bits (and mapped to the lower 8 data
>lines). Only the data register was 16 bits, and the drive would assert
>I/OCS16 when that was accessed and at no other time. Of course I have no
>idea how modern drives handle this...


This is still true for all the ones I've worked with (up to 528mb). Based
on how the larger ones work in older systems they should be identical. The
emulation is supposed to be WD1003 controller and based on the work I've
done with them
it rings true. This is why every 8bit system example you see the data path
is folded somehow to 8bits.

While reading the spec I discovered that Set_IO_8bit command and did a,
Wow this will help. Never could make it do what is written in the spec. I
suspect the drive never read the spec. If it worked I'm sure the 8bit
community
like those that did the GIDE, COCO IDE and others would have jumped on that.

Allison
Received on Mon Apr 17 2000 - 16:48:30 BST