Well, I would say a description of what is critical is important, not
asking how long a brick will stay square.  Under normal operation, I am
sure it will work fine for you, it is not MS Windows95 that likes to
lockup for no real reason.  But anyway, what is critical?, Timing? Data?
Outputs? Inputs?  Once you have figured that out, can implement
fail-safe methods of handling the problems.  A real-time clock/calendar
with a super-cap to back it up is good for keeping time (I use this, it
is good for over a week) , A EEprom for storing critical data, and if
you are worried about data just randomly getting corrupted, you can
incorporate a self test to constantly check memory and fire a reset if
something does change. Well, without a description of the application I
would say I have run out of guesses. (grin)
    Giles L. Honeycutt


Thanai Anantawatanawitaya wrote:
>
> Hi all,
>
> Does anyone know how long a PIC could works a certain code such as a real
> time clock which is never be interrupted or reset until it stops or hangs
> by itself?
>
> Let's assume that there is no bug in code at all and power supply is in a
> very good condition. Also watchdog is disabled. You may think this is a
> strange question but I think it's interesting because I'm developing a
> product that has to be powered all the time until user throw it away
> because he buys a new model, not because the old one is dead.
>
> Thanks in advance,
> Wiriya Sasisakulporn