5 Aug
2005
5 Aug
'05
8:05 a.m.
>>>> "Roger" == Roger Merchberger
<zmerch at 30below.com> writes:
Roger> Rumor has it that Jim Brain may have mentioned these words:
> Paul Koning wrote:
>
>> No... the classic PIO mode IDE registers are 8 bits wide, not 16.
>> Some devices may allow 16 bit access as an optimization, but 8
>> bit accesses is all you need.
>>
> The IDE command registers are all 8-bits wide, but the Data
> register is 16 bits wide. You have to support a 16 bit transfer in
> order to get the data from the sector buffer (256 16 bit transfers
> nets you 512 bytes of data, the IDE std sector). IN the newer 48
> bit addressing mode, the LBA registers grow from 8 bits to 16 bits
> as well.
It's almost time for 48 bit LBA for flashcards, but not quite yet...
Curious. I have some code here that usees 8 bit data buffer accesses
on one platform, and 16 bit accesses on another. The one I usually
run is the 16 bit case, but last I knew the 8 bit case still
worked...
paul