PIC powered by capacitor for 0,5 second

[flotulopex]

Hello,
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=1936&stc=1&d=118781343 6">

I intend to power a PIC (it's a 16F630 at the moment) throught a switch and detect a "power-OFF / power-ON" sequence.

In other words, when I press the button, the PIC is switched "ON" and a Port (i.e. pin 3) reads a HIGH level. PIC performs Task 1 as long as the power is not cut.

I would like to be able to release the button for half a second to detect the LOW level on the Port and then switch the PIC back ON again to perform Task 2.

If the power-OFF state is longer than 0,5 second, the PIC will normally perform Task 1 when the power comes ON again.

I tried with a 10µ capa and then with a 470µ one but I can't get it working, the PIC switches OFF immediately. The total "load" on the PIC is around 2mA during the time a release the button (= no direct power from the supply). The diode is a 1N4148.

Is what I'm trying to achieve possible that simple way or not? If yes, what should I change or add to my circuit?