watchdog reset

[Russ Poffenberger]

In article <1074 at brazos.Rice.edu> ehrlich at cs.psu.edu (Daniel Ehrlich) writes:
>X-Sun-Spots-Digest: Volume 8, Issue 105, message 9 of 12
>
>In article <718 at brazos.Rice.edu> titan.tsd.arlut.utexas.edu!kam at cs.utexas.edu (Katherine Minister Hosch) writes:
>
>Howdy all.  This has happened twice now, and I'm starting to get a little
>worried.  We have a standalone 4/260 that crashed the other day, leaving
>only the message (on the console):
>
>	   > watchdog reset
>

<Stuff deleted>

>My question is this:  what *causes* a 'watchdog reset', other than pushing
>the 'reset' button on the back of the machine?  In neither case was the
>button pushed.  
>

I have found that a watchdog reset can also occur in the case of other VME
errors such as a board generating an interrupt but not responding to the
interrupt acknowledge (IACK controlled by jumper PX04 on the backplane) or
by a similar event relating to Bus Grant. If a board requests the bus,
then when granted (controlled by jumper PX03 on the backplane) it does not
respond, you will get this. The thing to check is ALL of the jumpers on
your backplane.  Some boards require them in place (If the board doesn't
use it, it must be daisy chained to the rest of the boards after it) and
it must be out if the board does use it. (If it is in, the board may
ignore it, or worse, two boards may try to respond at the same time).  If
these are standard sun boards, check the requirements in the Sun manual:
Cardcage Slot Assignments and Backplane Configuration Procedures to make
sure your jumpers are correct. If they are not sun boards, you will have
to look through the manuals on the boards and decide what they need.
Generally DMA type devices need both IACK and BG3 out. Boards that just
generate interrupts need IACK out but BG3 in.  If you have more questions,
e-mail me.

Russ Poffenberger
Schlumberger Technologies
poffen at sj.ate.slb.com