HD64F2168 Datasheet, PDF (132/874 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

5.6.2 Interrupt Control Mode 1
In interrupt control mode 1, mask control is applied to three levels for IRQ and on-chip peripheral
module interrupt requests by comparing the I and UI bits in CCR in the CPU, and the ICR setting.
1. An interrupt request with interrupt control level 0 is accepted when the I bit in CCR is cleared
to 0. When the I bit is set to 1, the interrupt request is held pending.
EVENTI, KIN, and WUE interrupts are enabled or disabled by the I bit.
2. An interrupt request with interrupt control level 1 is accepted when the I bit or UI bit in CCR is
cleared to 0. When both I and UI bits are set to 1, the interrupt request is held pending.
For instance, the state when the interrupt enable bit corresponding to each interrupt is set to 1, and
ICRA to ICRD are set to H'20, H'00, H'00, and H'00, respectively (IRQ2 and IRQ3 interrupts are
set to interrupt control level 1, and other interrupts are set to interrupt control level 0) is shown
below. Figure 5.6 shows a state transition diagram.
1. All interrupt requests are accepted when I = 0. (Priority order: NMI > IRQ2 > IRQ3 > IRQ0 >
IRQ1 > address break …)
2. Only NMI, IRQ2, IRQ3, and address break interrupt requests are accepted when I = 1 and UI =
0.
3. Only NMI and address break interrupt requests are accepted when I = 1 and UI = 1.
All interrupt requests
are accepted
I0
I 1, UI 0
Only NMI, address break, and
interrupt control level 1 interrupt
requests are accepted
Exception handling execution
or I 1, UI 1
I0
UI 0
Only NMI and address break
interrupt requests are accepted
Exception handling
execution or UI 1
Figure 5.6 State Transition in Interrupt Control Mode 1
Figure 5.7 shows a flowchart of the interrupt acceptance operation.
Rev. 3.00, 03/04, page 92 of 830