Power-on reset. Start-up timer.

[mackrackit]

The MCLR pin needs to be pulled high or shut off.
If you shut it off it can be used as an INPUT.

Add this to your configuration to turn it off

_MCLRE_OFF

And this is a helpful thread
http://www.picbasic.co.uk/forum/showthread.php?t=543

[Lasse1]

Hi again.
Thank you for your fast answer. It was a helpful link you gave me, I learned a little bit moore. I tried booth "POR" and "PWRT" but unfortunal it didn´t solve the problem. Do you have some other idea? Otherwhise I have to try to solve it the hardwhere-way.
Friendly regards / Lasse

[mackrackit]

Did you try
_MCLRE_OFF

[Lasse1]

Yes. I did.
And to be clear I can say that I am complete sure that my problem depend on power-up. (If I set the PIC in the holder with the pwr-leg bended away, and then connect it after the unit is powered-up, the pic starts correct)
You don´t have any other idea?
Friendly regards / Lasse

[mackrackit]

I am not sure what you mean by pwr-leg?
Can you post how everything is connected using pin numbers in the description or a schematic?

[Lasse1]

Hello.
Sorry about my defenition. I mean the VCC-pin. And I dont think that it is relevant how other pins are connected. I tried different connections and have the same troubble. The thing is that it is one sekund interrupts in the power supply every five sekund, and cause of that it is a condensator connected to the power supply to keep the pic alive. That is working fine, the troubble occurs only when it is powered up, and only when the condensator is connected. This was working fine with a basic stamp but a pic is obviusly more critical.

[BrianT]

Slowly rising power supplies will trip a PIC up. There is a minimum dV/dT of something like 5 V/uSec needed. RTFM will find it. No amount of resets will recover a PIC that has been powered up slowly.

I had this problem with a current limited power supply that slowly rose in voltage as it had to charge a big cap.

Minimise input storage capacitors, or put them direct across your PSU before the power switch so they can supply a burst current to the PIC circuitry and get the Vdd up within the allowed time.

HTH
BrianT