Quote:
Originally Posted by TimCraig
I've never understood the && with the enable bit in the interrupt handler. If the interrupt isn't enabled, there will be no jump to the interrupt vector so that test will never be executed. Without the interrupt enabled, it's just an ordinary input pin.
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There is only one (low-priority) interrupt handler. It will be called when
any interrupt occurs, and the handler has to check all the possible sources in order to service the interrupt properly. The program won't know not to deal with a flag for a disabled interrupt unless you also check the associated enable bit. You don't really want a serial port interrupt to end up running the service routine for a "disabled" encoder.