h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 181

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Figure 5.10 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. When interrupt requests are sent to the interrupt controller, a control level 1 interrupt,
3. The I bit is then referenced. If the I bit is cleared to 0, the UI bit has no effect.
4. When an interrupt request is accepted, interrupt exception handling starts after execution of the
5. The PC and CCR are saved to the stack area by interrupt exception handling. The PC saved on
6. Next, the I and UI bits in CCR are set to 1. This disables all interrupts except NMI and address
7. A vector address is generated for the accepted interrupt, and execution of the interrupt
interrupt request is sent to the interrupt controller.
according to the control level set in ICR, has priority for selection, and other interrupt requests
are held pending. If a number of interrupt requests with the same control level setting are
generated at the same time, the interrupt request with the highest priority according to the
priority system shown in table 5.4 is selected.
An interrupt request set to interrupt control level 0 is accepted when the I bit is cleared to 0. If
the I bit is set to 1, only NMI and address break interrupts are accepted, and other interrupt
requests are held pending.
An interrupt request set to interrupt control level 1 has priority over an interrupt request set to
interrupt control level 0, and is accepted if the I bit is cleared to 0, or if the I bit is set to 1 and
the UI bit is cleared to 0.
When both the I bit and the UI bit are set to 1, only NMI and address break interrupts are
accepted, and other interrupt requests are held pending.
current instruction has been completed.
the stack shows the address of the first instruction to be executed after returning from the
interrupt handling routine.
break.
handling routine starts at the address indicated by the contents of that vector address.
Rev. 4.00 Jun 06, 2006 page 127 of 1004
Section 5 Interrupt Controller
REJ09B0301-0400