HD6432160 RENESAS [Renesas Technology Corp], HD6432160 Datasheet - Page 141

• Manufacturer Part Number: HD6432160
• Description: Hitachi 16-Bit Single-Chip Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

5.6.2
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.
For instance, the state transition when the interrupt enable bit corresponding to each interrupt is set
to 1, and ICRA to ICRC are set to H’20, H’00, and H’00, respectively (IRQ2 and IRQ3 interrupts
are set to control level 1, and other interrupts are set to control level 0) is shown below. Figure 5.5
shows a state transition diagram.
Figure 5.6 shows a flowchart of the interrupt acceptance operation.
1. If an interrupt source occurs when the corresponding interrupt enable bit is set to 1, an
2. According to the interrupt control level specified in ICR, the interrupt controller only accepts
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
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.
All interrupt requests are accepted when I = 0. (Priority order: NMI > IRQ2 > IRQ3 > address
break > IRQ0 > IRQ1 …)
Only NMI, IRQ2, IRQ3 and address break interrupt requests are accepted when I = 1 and UI =
0.
Only an NMI and address break interrupt request is accepted when I = 1 and UI = 1.
interrupt request is sent to the interrupt controller.
an interrupt request with interrupt control level 1 (priority), and holds pending an interrupt
request with interrupt control level 0 (no priority). If several interrupt requests are issued, an
interrupt request with the highest priority is accepted according to the priority order, an
interrupt handling is requested to the CPU, and other interrupt requests are held pending.
Exception handling execution
Interrupt Control Mode 1
All interrupt requests
or I
are accepted
Figure 5.5 State Transition in Interrupt Control Mode 1
1, UI
1
I
interrupt requests are accepted
Only NMI and address break
0
I
1, UI
I
0
0
UI
0
Only NMI, address break, IRQ2,
Exception handling
execution or UI
Rev. 2.0, 08/02, page 101 of 788
and IRQ3 interrupt requests
are accepted
1