Lpc2000

Ake,

I can almost feel your frustration: we've all been there!

I'm very interested in the outcome of this, as our own task for next 
week is to get the watchdog working on our own LPC2134-based system. 

I'm a bit surprised that no one has volunteered some working code. 
Surely someone out there is using this?

Unfortunately, as we haven't got there yet, I've nothing specific to 
suggest, other than a general strategy of getting something simple 
working first, and then building up to where you are. For example:

1. As simple as possible startup, initialisation (all peripherals 
disabled, all interrupts off etc.) and an application that 
initialises the watchdog and uses GPIO to signal what it's doing (and 
maybe reads to indicate whether or not the watchdog should be fed). 
In other words, the simplest possible program with a working 
watchdog. 

2. Same program, but with your normal initialisation and setup code, 
added incrementally. Still working?

3. Compare and contrast with your real application, particularly in 
how peripherals, interrupts etc. are managed.

In other words, get something simple working first, and build up from 
there. It'll take time, but maybe less time then starting from a 
larger system that doesn't work.

Hopefully, somewhere along the line, all will become obvious.

By the way, are you running your code using an emulator connected? 
I've seen strange behaviour in the past with watchdogs enabled. Try 
running stand-alone, if you haven't done so already.

As a final suggestion, based on what you say below, I'd look very 
carefully at every location interrupts are enabled/disabled (at the 
peripheral level, at the VIC and at the CPSR). Also at your startup 
and IRQ dispatch code. Maybe the processor is resetting and re-
initialising stuff without you realising? maybe throwing an exception 
you haven't noticed?

As a final comment: 'though no doubt it feels like it, it's not time 
wasted: you'll know way more about the watchdog and processor at the 
end of all this then when you started.

Good luck!

Brendan


--- In lpc2000@yahoogroups.com, "Ake Hedman, eurosource" <akhe@b...> 
wrote:
>
> WD story update
> 
> I changed the code to have the watchdog raising an IRQ instead of a 
> RESET.  I initialize stuff and then go in in a while loop.
> 
> 1.) With interrupts enabled but no interrupt channel active this 
will 
> not trigger the watchdog. Why?
> 
> 2.) With one of the interrupt channels active ( UART0 writing some 
> characters ) the watchdog works. Without a dog feed the watchdog is 
> triggered and with a feed it runs fine. However what I initialize 
WDTC 
> with does to seem to matter. I always get about 4 ms period when I 
> toggle a pin in the WD interrupt (60MHz clock).
> 
> Is this behaviour recognized by anyone? Please!
> 
> BTW the chip is LPC2138
> 
> /Ake
> 
> 
> dr_danish_ali wrote:
> 
> > Ok Ake, here's my dumb suggestion:
> >
> > Try enabling the watchdog, but just to interrupt not reset?
> > You'll need an interrupt handler / VIC channel to do it - can you 
> > spare one?
> > That ISR need just raise a flag for now.
> >
> > Once the watchdog is fed and running happily, you might then be 
able 
> > to enable resets on
> > it.
> >
> > Hope this helps,
> > Danish
> >
> > --- In lpc2000@yahoogroups.com, "Ake Hedman, eurosource" 
<akhe@b...> 
> > wrote:
> > >
> > > I am still trying to solve my problems with the watchdog.
> > >
> > > I have now scaled away most stuff of my application and can see 
that 
> > the
> > > problem occurs when either of three interrupts occur 
(UART0/UART1/I2C0)
> > > in the system. Without the watchdog everything works fine but 
if I
> > > enable the watchdog everything crashes. I have tried to just 
enable and
> > > trig one of the interrupts in turn but the situation is the 
same.
> > >
> > > I'm totally out of clues at the moment so any (also things that 
> > might be
> > > considered dumb) are very welcome.
> > >
> > > Regards
> > > /Ake
> >
> >
> >
> >
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> -- 
>  ---
> Ake Hedman (YAP - Yet Another Programmer)
> eurosource, Brattbergavägen 17, 820 50 LOS, Sweden
> Phone: (46) 657 413430 Cellular: (46) 73 84 84 102
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