Although I can understand the difference between programmed IO (PIO) and interrupt (INT) transfers, still there is something vague.
In PIO, the processor repeatedly checks READY pin to see if the device is ready. However, in interrupt mode, the processor checks the INT pin at the end of the instruction cycle.
My question is, in interrupt mode, the processor still has to repeatedly checks the INT pin. I know that in this mode, the external device send the interrupt signal, but how processor becomes aware of that interrupt? The processor has to repeatedly check the INT pin on every cycle (or instruction cycle). Doesn't it?