UPD78F0138 NEC, UPD78F0138 Datasheet - Page 372

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

372
Interrupt request held pending
Interrupt request held pending
××IF:
××MK: Interrupt mask flag
××PR: Priority specification flag
IE:
ISP:
Interrupt request flag
Flag that controls acknowledgement of maskable interrupt request (1 = Enable, 0 = Disable)
Flag that indicates the priority level of the interrupt currently being serviced (0 = high-priority interrupt
servicing, 1 = No interrupt request acknowledged, or low-priority interrupt servicing)
Interrupt request held pending
Figure 17-7. Interrupt Request Acknowledgement Processing Algorithm
Yes
No
Vectored interrupt servicing
interrupt request among those
simultaneously generated
Any high-priority
with
IE = 1?
CHAPTER 17 INTERRUPT FUNCTIONS
PR = 0?
No
Yes
User’s Manual U16228EJ2V0UD
Yes (High priority)
No
No
those simultaneously generated
Vectored interrupt servicing
interrupt request among
interrupt request among
those simultaneously
Any high-priority
Any high-priority
with
generated?
ISP = 1?
IE = 1?
MK = 0?
PR = 0?
Start
IF = 1?
PR = 0?
Yes (interrupt request generation)
Yes
No (Low priority)
No
No
Yes
Yes
No
No
Interrupt request held pending
Interrupt request held pending
Interrupt request held pending
Interrupt request held pending
Yes
Yes