384
CHAPTER 22 INTERRUPT FUNCTIONS
User’s Manual U12697EJ3V0UM
22.7 Maskable Interrupt Acknowledgment Operation
A maskable interrupt can be acknowledged when the interrupt request flag is set (1) and the mask flag for that
interrupt is cleared (0). When servicing is performed by macro service, the interrupt is acknowledged and serviced
by macro service immediately. In the case of vectored interruption and context switching, an interrupt is acknowledged
in the interrupt enabled state (when the IE flag is set (1)) if the priority of that interrupt is one for which acknowledgment
is permitted.
If maskable interrupt requests are generated simultaneously, the interrupt for which the highest priority is specified
by the priority specification flag is acknowledged. If the interrupts have the same priority specified, they are
acknowledged in accordance with their default priorities.
A pending interrupt is acknowledged when a state in which it can be acknowledged is established.
The interrupt acknowledgment algorithm is shown in Figure 22-11.
