thanks again Bruce,

I have one main input pin which needs to wake up the unit

so what you are saying is that if it is NOT that pin when it comes out of SLEEP then by elimination it must be the ULPWU pin ?

so then i would check the state of that pin, i.e. there is no bit that says which specific pin caused the wake up ? (i know there is not for the ULPWU)

also sorry if i am being dense here but can you explain the mismatch deal some more?
so if i read or write to *any* pin it will clear that mismatch?