Lpc2000

>How I solved it:
>
>I have replaced all dog-feeds with
>
> mycpsr = disableIRQ();
> WDFEED = 0xAA; WDFEED = 0x55;
> restoreIRQ( mycpsr );
>
>where disableIRQ and restoreIRQ is from R O Software
Precisely my point. It appears as if this is an extra undocumented 
feature.

Ken Wada

--- In lpc2000@yahoogroups.com, Tom Walsh <tom@o...> wrote:
>
> Ake Hedman, eurosource wrote:
> 
> >OK Guys,
> >
> >I can confirm that the WD problem is solved in my case. Thanks a 
lot 
> >all!  (Description of solution below.)
> >
> >I think this definitely should be mentioned in the err data sheets 
for 
> >the affected processors (or clearly in the UM)  as the resulting 
> >symptoms are such that the problem is very hard to debug..
> >
> >Cheers
> >/Ake
> >
> >
> >How I solved it:
> >
> >I have replaced all dog-feeds with
> >
> >        mycpsr = disableIRQ();
> >        WDFEED = 0xAA; WDFEED = 0x55;
> >        restoreIRQ( mycpsr );
> >
> >where disableIRQ and restoreIRQ is from R O Software
> >
> >  
> >
> 
> I've been following this thread with interest as I expected to use 
the 
> watchdog in my application.  The old design used a MAX690 where you 
> would toggle the input to keep the watchdog happy.  This worked well 
for 
> us as the foreground software would set the pin high and the 
interrupt 
> routines would reset it low.  This ensured that both sections of the 
> program were operating okay.  Foreground did non-time-critical tasks 
> while the background serviced realtime critical tasks & 
communications 
> over RS485.
> 
> I had expected to do something similar with the LPC2000 parts.  Feed 
the 
> watchdog with 0xaa from the interrupt layer and then feed it with 
0x55 
> from the foreground.  It was expected that even if the watchdog 
received 
> something like this, it would still be fine:
> 
> 0xaa, 0xaa, 0xaa, 0x55, 0xaa, 0xaa, 0xaa, 0xaa, 0x55 ....
> 
> 
> What value is a watchdog that requires you to carefully feed it, it 
> sounds as if the watchdog is very fragile?  I noticed that Philips 
> Applications people studiously stayed out of this thread about the 
> watchdog!  I suspect that the watchdog is severly broken and they 
did 
> not want to comment on it?
> 
> 
> Regards,
> 
> TomW
> 
> -- 
> Tom Walsh - WN3L - Embedded Systems Consultant
> http://openhardware.net, http://cyberiansoftware.com
> "Windows? No thanks, I have work to do..."
> ----------------------------------------------------
>