Re: LPC2138 Watchdog

Started by Jayasooriah March 16, 2006
Hi Juergen,

You cannot use the watchdog as a periodic timer interrupt because on 
watchdog interrupt the CPU is reset almost equivalent to an external reset.

Jaya

--- In lpc2000@lpc2..., rekerj@... wrote:
 >
 > Hi,
 >
 > how can I use the watchdog as a periodic timer?
 >
 > >using the watchdog with interrupt has two options, you use it as a
 > >periodic timer interrupt or for debugging,...
 >
 > The information i've found in the manual is:
 > "The Watchdog Interrupt Flag is set when the watchdog times out. This

flag is cleared when any reset occurs."
 >
 > Due to this it isn't possible to clear the Watchdog Interrupt Flag by 
software. But when I can't clear this flag, I can handle this interrupt 
only one time and that wouldn't be sense of a periodic timer.
 >
 > Juergen

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An Engineer's Guide to the LPC2100 Series

Jaya: the LPC allows you to choose between reset and interrupt when 
Watchdog is triggered by means of the WDMOD register. If you set 
WDMOD to 0x01, you'll get a normal IRQ through the VIC when the 
watchdog is triggered; if you set it to 0x03, you will get a reset 
(which is similar to a hardware reset).

Guille

--- In lpc2000@lpc2..., Jayasooriah <jayasooriah@...> wrote:
>
> Hi Juergen,
> 
> You cannot use the watchdog as a periodic timer interrupt because 
on 
> watchdog interrupt the CPU is reset almost
equivalent to an 
external reset.
> 
> Jaya
> 
> --- In lpc2000@lpc2..., rekerj@ wrote:
>  >
>  > Hi,
>  >
>  > how can I use the watchdog as a periodic timer?
>  >
>  > >using the watchdog with interrupt has two options, you use it 
as a
>  > >periodic timer interrupt or for
debugging,...
>  >
>  > The information i've found in the manual is:
>  > "The Watchdog Interrupt Flag is set when the watchdog times out.

This 
> flag is cleared when any reset occurs."
>  >
>  > Due to this it isn't possible to clear the Watchdog Interrupt 
Flag by 
> software. But when I can't clear this flag, I can
handle this 
interrupt 
> only one time and that wouldn't be sense of a
periodic timer.
>  >
>  > Juergen
> 
> Send instant messages to your online friends 
http://au.messenger.yahoo.com
>