Peter & Hans
Hans you got it right.
Now all you have to do is answer one question.
How many RETI's are necessary when you go back from only ONE interrupt routine back to the root routine during power up (a single high level interrupt case)? If you still say two, I will look for a large cone paper hat. Going to the main root routine is not an interrupt routine although it may look that way to you. That should be where you start your stack. If you get only one interrupt be it high or low level there is only one address on the stack. Popping the stack twice will not unwind the stack properly. I see in PM they do a pop stack twice just in case at power up there may be a level on the external pins, i.e. INT0 or INT1 that may go to a sub routine. But they reset or init the stack to it's lowest address after that. Like I said before Peter, what works for you is just fine with me, arguing this point further is not necessary.

Post