Lpc2000

--- In lpc2000@yahoogroups.com, Tom Walsh <tom@o...> wrote:
> 
> 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..."
> ----------------------------------------------------
>
It sounds like you have described a really robust watchdog timer!! 
It detects and stops fragile software.

It's function is NOT to make life easy for the software developer, it
is to make the system more reliable for the end user by forcing good
software and hardware design.  The watchdog kick should always be
cosecutive instructions to reduce the possibility of random events
from kicking the timer.

At least, that was the philosophy of the ASIC teams that I have worked
with.

--Dave