stack

[gjs_rsdi]

I am using timer0 as a time-out indicator, to stop "while" functions and begin others. I don't want to go back to the same "while" after the interrupt.
that make the stack full after a certain time.
I would like to clear the stack. It is posible ? or have some other technics
not to fill the stack when not returning to the same place.
In assembler is simple, calls go back to the next line, so no stack overflow problems.
Joseph

[asmallri]

[Mark]

You could also use a state machine inside a while loop. When the timer0 interrupts, change states.

[PCM programmer]

I also felt that the program structure could probably be changed, and
then this problem would not be an issue.

Look at various threads in the forum that show how to do multitasking:
http://www.ccsinfo.com/forum/viewtopic.php?t=17189&highlight=multitasking

[gjs_rsdi]

Thanks for the answers
my program is a multitasking one and it works O.K. also with the hardware. The reset problem I solved by NOSTVREN in the fuses.
My program should go to an other place if time-out occured and not executing the "while".
In any case, my question remain "it is posible to clear the stack, not by reset?"
Joseph

[Mark]

What PIC??

[gjs_rsdi]

The micro is 18F252
Joseph

[Ttelmah]

It really does sound 'messy'. Overriding the stack, to my mind reflects the possibility of quite dangerous programming. However it is do-able. All you need to do, is reset the stack _pointer_. Values left 'in' the stack, do not matter. The '0' stack address has no RAM, and allways contains 0, so setting the pointer back to zero, effectively resets the stack, and will also clear error conditions if present.

[Mark]

For PIC18's you can do as RJ pointed out to reset the pointer but there are ASM instructions 'POP' and 'PUSH' which allow you to remove addresses from the stack as well as put addresses on the stack.

[gjs_rsdi]

tahks for the answers, realy helpfull
joseph