Re: Can I noise hang a ColdFire forever...?

Hi Karl
Thanks for your time..
I did several "garage" tests with a ColdFire and a HC08 mcu.
I conclude, although garage tests and different layouts,  that after 
ColdFire hang up
for these situations, and the watchdog is not enough to bring it back.
I set on the whole interrupts possible to reset it...
In worst test conditions, a HC08 doesn´t reset, I mean, keep 
working.Well..much simpler machine...
With a external watchdog the ColdFire is always brought back via reset pin.
Of course, I´m considering ( and it didn´t happens in my tests) the chip 
didn´t get damaged due to theses noise, otherwise It would not work back 
after a hw reset...
I decided to use the a ST 4 pin smart reset/watchdog device wich costs  less 
then U$1 to improve
the design robustness...
Thanks everybody for the help !!
Ricardo Raupp

----- Original Message ----- 
From: "Karl Paton" <[email protected]>
To: "Ricardo" <[email protected]>
Sent: Friday, March 07, 2008 5:31 PM
Subject: Re: [ColdFire] Can I noise hang a ColdFire forever...?


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> Ricardo,
>
>> *- Is there a way to know if ColdFire is simply stopped due to lack of 
>> enabled protections from the programmer fail (me!) , or stopped because 
>> the core got latched up or some condition like this, due to such 
>> disturb?Ex. verifying current consuption?*
>
> I don't know the Coldfire well but with the 68K enough noise can lead to a 
> double bus fault (exception upon an exception) which will halt the 
> processor.
> If the double bus fault monitor is enabled the processor will reset itself 
> but, if not, it will just halt/hang and can only be restarted with an 
> external reset.
>
> It seems the Coldfire has a similar "fault-on-fault" halt which might the 
> culprit.  Maybe worth looking at?
>
> Regards,
> Karl
>
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