NY8A051H provide two kinds of interrupt: one is software interrupt and the other is hardware interrupt. Software interrupt is caused by execution of instruction INT. There are 6 hardware interrupts:
Timer0 overflow interrupt.
Timer1 underflow interrupt.
WDT timeout interrupt.
PB input change interrupt.
External interrupt..
LVD interrupt
GIE is global interrupt enable flag. It has to be 1 to enable hardware interrupt functions. GIE can be set by ENI instruction and clear to 0 by DISI instruction.