gnupic: Interrupt Problems?!?
Subject:
Re: Interrupt Problems?!?
From:
Jeff Jackowski ####@####.####
Date:
8 Dec 2002 23:22:00 -0000
Message-Id: <Pine.OSF.4.44.0212081708550.422047-100000@fly.hiwaay.net>
On Sat, 7 Dec 2002, Wayne Patterson wrote:
>My app seems to get hung up from time to time coming back from an interrupt.
>And it is always in the same place. If the interrupt happens while the
>process is in a lookup table it gets hungup in an endless loop. I am still
>very new at all this but I think it has something to do with the program
>counter. I save the status reg and the contents of w and then service the
>interrupt and restore them at the end right be for I return for the
>interrupt. From all that I have see and read this is all that is needed. Is
>it necessary to save the program counter reg and reinstate it as well? If is
>so, would it be as strait forward as the routine for the status reg?
>Thanks for any help!
>Wayne
For the 14-bit parts, from what I can tell, unless you really know what
you are doing (and most of the time, even if you do), you need to save and
restore the upper byte part of the program counter. You'll see that
Microchip does this in their examples in the documentation. If your code
uses the memory indirection hardware in the interrupt, than the
indirection's address should also be saved and restored.
--
Jeff Jackowski
http://ro.com/~jeffj/
