I started today takng some legacy code running on the MPC5200B, and have to add an optical encoder which has been hooked up to ETH16 and USB6 as two input GPIO pins. These pins were chosen as one of the will be supplying an interrupt (ETH16 is documented as allowing a simple GPIO interrupt), and the other will be read during the handler of that interrupt.
I'm a bit confused as to how to implement the handler. There is already a handler for the external IRQ, handling core stuff which I'd rather not touch if I don't have to; but it is unclear to me where the GPIO simple interrupts are vectored to. Do they go to the same vector and then the handler has to distinguish between them?