Interrupt Request Enabled For Multiple Interrupt During Interrupt Servicing - NEC PD78081(A) User Manual

Table 12-4. Interrupt Request Enabled for Multiple Interrupt during Interrupt Servicing
Interrupt
during processing
Non-maskable interrupt
Maskable interrupt
Software interrupt
Remarks 1.
188
CHAPTER 12 INTERRUPT FUNCTION
Multiple Interrupt
Non-maskable
Request
Interrupt
Request
ISP=0
ISP=1
E : Multiple interrupt enable
2.
D : Multiple interrupt disable
3.
ISP and IE are the flags contained in PSW
ISP=0 : An interrupt with higher priority is being serviced
ISP=1 : An interrupt request is not accepted or an interrupt with lower priority is being
serviced
IE=0 : Interrupt request acknowledge is disabled
IE=1 : Interrupt request acknowledge is enabled
4.
PR is a flag contained in PR0L, PR0H, and PR1L
PR=0 : Higher priority level
PR=1 : Lower priority level
Maskable Interrupt Request
PR=0
IE=1 IE=0
D D D
E E D
E E D
E E D
PR=1
IE=1 IE=0
D D
D D
E D
E D