Lpc2000

I'm having trouble hitting the watchdog on the 2103.  It works just 
fine without IRQs, but after I enable interrupts I can no longer feed 
it.  I am disabling interrupts around the feed so it is atomic, and I 
know the feed works becasue I call the same code in the init 
function.  I've tried using the standard __enable_interrupt 
__disable_interrupt functions in IAR and I've tried directly 
manipulating the CPSR as per the errata sheet with no luck.  Any 
advice?

Andy

One trap I fell into was that I was running my code in _user_ mode
rather than _system_ mode on the arm processor.

In user mode, you can't manipulate the interrupt enable / disable bits.

The rowley-supplied interrupt enable / disable routines assume you're
in system mode and don't work in user mode. It might be the same for
IAR (I don't know).

My way out? I now have a SWI routine to feed the watchdog
(IRQ automatically disabled - all you must do is disable FIQ
during the feed).

Hope this helps,
Danish
--- In lpc2000@yahoogroups.com, "Langosta39" <ahuska@...> wrote:

>
> I'm having trouble hitting the watchdog on the 2103.  It works just 
> fine without IRQs, but after I enable interrupts I can no longer feed 
> it.  I am disabling interrupts around the feed so it is atomic, and I 
> know the feed works becasue I call the same code in the init 
> function.  I've tried using the standard __enable_interrupt 
> __disable_interrupt functions in IAR and I've tried directly 
> manipulating the CPSR as per the errata sheet with no luck.  Any 
> advice?
> 
> Andy
>

Danish Ali wrote:

>One trap I fell into was that I was running my code in _user_ mode
>rather than _system_ mode on the arm processor.
>
>In user mode, you can't manipulate the interrupt enable / disable bits.
>
>The rowley-supplied interrupt enable / disable routines assume you're
>in system mode and don't work in user mode. It might be the same for
>IAR (I don't know).
>
>My way out? I now have a SWI routine to feed the watchdog
>(IRQ automatically disabled - all you must do is disable FIQ
>during the feed).
>
>  
>

That is a good suggestion, thank you.

TomW

-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
----------------------------------------------------

--- In lpc2000@yahoogroups.com, Tom Walsh <tom@...> wrote:

> >My way out? I now have a SWI routine to feed the watchdog
> >(IRQ automatically disabled - all you must do is disable FIQ
> >during the feed).
> >
> >  
> >
> 
> That is a good suggestion, thank you.

A while back we discussed the SWI method and its benefits in another
thread.  If I recall correctly, I posted the SWI equivalent for the
code snippet posted by Danish Ali.

Have a look at atomicFeed() example here:

 http://groups.yahoo.com/group/lpc2000/message/15358

Jaya