Lpc2000

--- In lpc2000@yahoogroups.com, "relentless_6995" <bobd@...> wrote:

> Turning on WDT for the first time. I was testing it a few different 
> ways. One way involves a Data Abort IRQ. My data abort IRQ falls into 
> an endless loop (on purpose). It seems that when I create an illegal 
> access to trigger the data abort IRQ the WDT never fires. The code 
> enters the Data Abort IRQ, hits my endless loop and sits there 
> forever - no WDT reset! Anyone know why?

It is because the watchdog timer on LPC is not wired to the Reset
interrupt priority level of ARM7.  Thus the Data Abort exception that
you are not dismissing locks out watchdog reset.

You could go down the chain (Data Abort, FIQ, IRQ, Prefetch Abort,
then Undefined Instruction/SWI to discover at what level the watchdog
reset is wired to ... I would if I relied on the watchdog to get me
out undefined situations, but then I only use the watchdog to trigger
a reset when I want it to.

It is not clear if this behaviour in LPC is a design or implementation
error.

Jaya