At 19:12 Uhr +0200 28.7.2000, Henry B. Hotz wrote:
>I know which way the terminators are labeled and I had them in with
>the little pin-1 mark next to the arrow on the disk controller card.
>But just for the hell of it I tried putting them in backwards and it
>works now.

Ouch. I know the mixture of rage and joy well.  ;)

>The terminator pulls the bus lines to a reference voltage with a
>certain resistance in order to damp out signal reflections from the
>end of the wire.  Since the resister pack is connected to both Vterm
>and Ground reversing the pack should have the effect of shifting the
>reference voltage and increasing the load on signal drivers, but
>should have no effect on the damping, I think.  So maybe this makes
>some kind of sense?

Umm -- are you sure your SIL resistors are wired that way? I just measured
the collection of SILs I pulled from all sorts of drives over time, and
there are both the type you describe


-------------------------o
| | | | | |
R R R R R R
| | | | | |
o o o o o o
| | | | | |
R R R R R R
| | | | | |
-------------------------o


and

-------------------------o
| | | | | | |
R R R R R R R
| | | | | | |
o o o o o o o


-- whether by accident or design, I can't tell.
I can imagine that taking one type for the other can give some interesting
effects...

	hauke



--
"It's never straight up and down"     (DEVO)