9 Dec
2004
9 Dec
'04
3:43 p.m.
I thought they were somehow "ATA compliant". I
assume you're talking about the interface between the drive and the
controller, right?
--
The issue is what data bus width is assumed during DMA transfers.
16 bits is 'normal'. Apparently, it was possible to do 8 bit DMA
transfers on early drives. I've not looked at the interface for
CF. Guess it's possible 8 bits is supported there as well.
9 Dec
9 Dec
5:43 p.m.
the real ATA spec was not "approved" until 1990 or so - the hazards of
being the first standard for such an interface. The ATA-1 and ATA-2 at
least had a hardware line going to the drive to switch between 8 and 16 bit
data paths to the drive. Any new drive would have to indicate compatibility
with ATA-1 or ATA-2 to work with an older controller. It loosk like ATA-3
or 4 did away with an 8 bit transfer capability. Obviously no one is making
ISA IDE controllers anymore, but one could design one that worked perfectly
well with the new drives. One does not have to assume that the data bus to
the drive must match the data path to memory
At 04:43 PM 12/09/2004, you wrote:
I thought they were somehow "ATA
compliant". I
assume you're talking about the interface between the drive and the
controller, right?
--
The issue is what data bus width is assumed during DMA transfers.
16 bits is 'normal'. Apparently, it was possible to do 8 bit DMA
transfers on early drives. I've not looked at the interface for
CF. Guess it's possible 8 bits is supported there as well.
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