Hi Gil,

your fault was "clr IE0" before "RETI".

As you tell, your ISR consume many time. And so it is possible, that the next 1->0 transition occur, before the ISR was finished. And then "clr IE0" cause, that this event was lost.

Please watch, that the flag was automatically cleared by hardware.
Only, if you really want to skip all events occured already during the ISR, this flag must be cleared again.

Nevertheless its always better to hold any ISR as short as possible. Especially, if many interrupt sources must be served.


Peter