18 Apr
2015
18 Apr
'15
7:48 a.m.
On Sat, 18 Apr 2015, Cory Smelosky wrote:
I was writing this when you sent the above reply ;)
On Apr 18,
2015, at 02:55, Eric Smith <spacewar at gmail.com> wrote:
My memory is probably faulty about exactly what the WD suffix means. I
still think it's 16-bit "ultra" (1), but Wikipedia says that ultra (1)
is single-ended or HVD, ultra 2 is LVD or HVD, and ultra 3, 320, and
640 are LVD only.
The manual did confirm WD is definitely HVD which explains my issues.
I recall some sort of Ultra bit in it as well. ST34573WD
ST32550ND
W -- wide
N -- narrow
WD -- wide differential
ND -- narrow differential
You'll need a converter. These type of differential drives can't be
connected directly to a single ended bus, wide or narrow. If you do, you
are connecting one side of the differential pair to ground, and these
drives don't like that. There are also signal differences, see the pinouts
for wide and wide differential and look at the pin numbers for attention,
busy, ack, reset, etc. Later LVD devices could detect which sort of bus
they were connected to, but these drives can't.