sleep when pressing a button on keypad

[bfran.1]

My target is :

my device when the main run is OFF = SLEEP

Then its right this code ?

When i pressed for a time > 300 mses button (OFF/on ) my device must wakeup , my button il connected to pin wakeup

this is my code

Which timer and i must use for this case (timer one pulse ) ?

Is right write the sleeep routune before the main and when i press yhe button on/off for a time >300msec mcu wakeupThanks