Lpc2000

See "USAGE NOTES ON WATCHDOG RESET AND EXTERNAL START" on page 214 of
the 2124 User Manual (Dated May 03, 2004). Does this solve your
problem?

--- In lpc2000@yahoogroups.com, "bobbruce000" <bobbruce000@y...> 
wrote:
> --- In lpc2000@yahoogroups.com, "philips_apps" <philips_apps@y...> 
wrote:
> > What LPC2000 part are you using? Is it a 48-pin (LPC2104/5/6) or 
> > 64/144-pin (LPC2114/2124/2212/2214 & LPC2119/2129/2194/2292/2294) 
> > device?
> 
> It is a 64 pin device.  LPC2124 to be precise.  I also have a
> LPC2106 circuit, and the watchdog seems to work okay on that.
> 
> I stripped the code down to a minimal example.  The assembly
> stub has only two instructions (initialize sp, and jump to
> main()).  Interrupts are not enabled.  On the LPC2106 the
> output pin goes low for a few seconds, toggles for a few
> seconds, and then repeats as the chip is reset by the watchdog.
> On the LPC2124, the cycle only happens once.  Then the chip
> freezes up and requires an external reset.
> 
> ----------------------------------------------------------
> int
> main(void) {
>   int i;
>   
>   IO0DIR = 0x00000040;
>   IO0CLR = 0x00000040;
>   // Ground the pins for a few seconds
>   for (i = 20000000; --i >= 0;) { 
>     continue;
>   }
>   WDTC   = 20000000;
>   WDMOD  = 0x03;
>   WDFEED = 0xaa;
>   WDFEED = 0x55;
>   // Toggle until the watchdog reset triggers
>   for (;;) {	
>     IO0CLR = 0x00000040;
>     IO0SET = 0x00000040;
>   }
> }
> ----------------------------------------------------------
> 
> > --- In lpc2000@yahoogroups.com, "bobbruce000" <bobbruce000@y...> 
> > wrote:
> > > I am having problems recovering after a watchdog reset.
> > > I enable the watchdog, then to test it, I put the cpu
> > > into a loop, toggling a pin connected to a logic probe.
> > > If I set the reset to, say, 3 seconds, then right
> > > on time the toggling stops.  So the watchdog reset
> > > is triggered.
> > > 
> > > But the processor never comes back to life.  I have to
> > > ground the reset pin to get it to come back.  How does
> > > a watchdog reset differ from a hardware reset?  Are there
> > > some components (PLL?, UART?, TIMER?) that don't get
> > > reset?