More 11/45

Pete Turnbull pete at dunnington.plus.com
Fri Mar 31 01:53:45 CST 2006


On Mar 30 2006, 19:09, Jay West wrote:

> I enter and run the Line Time Clock Interrupt test from that webpage,
and
> the system halts at location 4. How on earth? Does the 11/45 have
some
> interrupts to specific locations for things like power fail or
something?
> Should a unexpected trap to location 4 mean something special to me?

I just had another thought.  Standard traps for errors and software
traps start at 4, and zero is reserved.  Normal interrupt vectors for
hardware devices use the area from 100 up to 400.  000000 is reserved,
so if anything uses that as a vector, it's because you have some
hardware fault.

My guess would be something along the lines of a hardware device
generating an interrupt, but apparently giving 000000 as a vector
instead of the true value intended.  Unlikely all three of your LTCs
would do the same thing.  Could be the CPU reading zeros due to a fault
in the interrupt logic, as Tony suggested.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York



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