Strange DSP56F807 problem

Started by Yochum, William January 17, 2003

I have recently found a very unusual problem that to the best of my
knowledge appears to be in the 807 hardware. I'm hoping the gurus on this
list might provide some input.

I have a situation where I am servicing an interrupt, and I'm allowing a
higher priority timer interrupt to preempt me. If I try to disable the
timer interrupt (using a BFCLR instruction), right before the timer
interrupt occurs, it appears like the processor vectors off somewhere other
than the normal interrupt handler.

Specifically in my case, it appears to jump to the reset vector (but without
performing a reset).

If I suspend interrupts before and after the BFCLR instruction I never have
a problem.

Has anyone on this list ever witnessed any similar behavior? I'm not
interested in any work-around -- just confirmation that this problem exists.

William C. Yochum Microwave Data Systems Inc.
Principal Eng./Software 175 Science Parkway
Phone: (585) 242-8319 Rochester, NY 14620
FAX: (585) 241-5590 USA