r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 165

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

5.6.1
In interrupt control mode 0, interrupt requests except for NMI are masked by the I bit of CCR in
the CPU. Figure 5.3 shows a flowchart of the interrupt acceptance operation in this case.
1. If an interrupt source occurs when the corresponding interrupt enable bit is set to 1, an
2. If the I bit is set to 1, only an NMI interrupt is accepted, and other interrupt requests are held
3. Interrupt requests are sent to the interrupt controller, the highest-ranked interrupt according to
4. When the CPU accepts an interrupt request, it starts interrupt exception handling after
5. The PC and CCR are saved to the stack area by interrupt exception handling. The PC saved on
6. Next, the I bit in CCR is set to 1. This masks all interrupts except NMI.
7. The CPU generates a vector address for the accepted interrupt and starts execution of the
interrupt request is sent to the interrupt controller.
pending. If the I bit is cleared, an interrupt request is accepted.
the priority system is accepted, and other interrupt requests are held pending.
execution of the current instruction has been completed.
the stack shows the address of the first instruction to be executed after returning from the
interrupt handling routine.
interrupt handling routine at the address indicated by the contents of the vector address in the
vector table.
Interrupt Control Mode 0
Rev. 1.00 Sep. 19, 2008 Page 135 of 1342
Section 5 Interrupt Controller
REJ09B0467-0100