Hi, I'm just forwarding a question to the list from a friend of mine
with a very strange problem with interrupts on a 71:

>    A test program which responds to an interrupt on RB0 by running an ISR
 which simply
>flashes a different LED on a test rig from the LED flashed by the main program
 works
>perfectly on a PIC16C84.
>    However on blowing the program into a windowed EPROM version of a PIC16C71,
 the
> program works once only on asserting an interrupt. It returns to the main
 program
> normally but will not accept further interrupts. When the reset button is
 pressed,
> interrupts are still not enabled. The only way to re-enable them is to turn
 off the
> power and then interrupts will work once only again.

I have had a look at the code and it is straightforward enough, with no
obvious errors. It seems wierd that not even a normal reset will get it
to work again, only a power-on reset. What could be causing this to
happen?

Alex Holden.