If I use the pin change interrupt (mega88) & am responding to a pin change interrupt (this is working so far), obviously no nested interrupts will occur (unless I enable interrupts in an interrupt--BAD BAD). However, if the SAME pin changes state while I'm busy processing the first PC interrupt, will another PC interrupt fire at the return from the first interrupt? That is, does the PC interrupt capture changes on a given pin whilst it is being handled? I really need to detect/remember changes such as these so I don't "miss" any edges. I suppose I could simply poll after the interrupt is complete, but there might be a long poll delay compared with the IRQ quick response.
The data sheet is not clear on what/when a "change" is detected (or more exactly, when a change is NOT noticed).