Section 5
Interrupt Controller
Rev. 1.00 Mar. 12, 2008 Page 93 of 1178
REJ09B0403-0100
Table 5.6
Operations and Control Signal Functions in Each Interrupt Control Mode
Interrupt
Setting
Interrupt Acceptance Control
3-Level Control
Default Priority
Control Mode
INTM1
INTM0
I
UI
ICR
Determination
T (Trace)
0 0
0
O IM —
PR
O
—
1
1
O IM IM
PR
O
—
[Legend]
O:
Interrupt operation control performed
IM:
Used as an interrupt mask bit
PR: Sets
priority
—: Not
used
5.6.1
Interrupt Control Mode 0
In interrupt control mode 0, interrupts other than NMI are masked by ICR and the I bit of the CCR
in the CPU. Figure 5.4 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
interrupt request is sent to the interrupt controller.
2. According to the interrupt control level specified in ICR, the interrupt controller accepts 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.
3. If the I bit in CCR is set to 1, only NMI and address break interrupt requests are accepted by
the interrupt controller, and other interrupt requests are held pending. If the I bit is cleared to 0,
any interrupt request is accepted. KIN, WUE, and EVENTI interrupts are enabled or disabled
by the I bit.
4. When the CPU accepts an interrupt request, it starts interrupt exception handling after
execution of the current instruction has been completed.
5. The PC and CCR are saved to the stack area by interrupt exception handling. The PC saved on
the stack shows the address of the first instruction to be executed after returning from the
interrupt handling routine.
6. Next, the I bit in CCR is set to 1. This masks all interrupts except for NMI and address break
interrupts.
Summary of Contents for H8S Family
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Page 70: ...Section 1 Overview Rev 1 00 Mar 12 2008 Page 22 of 1178 REJ09B0403 0100...
Page 108: ...Section 2 CPU Rev 1 00 Mar 12 2008 Page 60 of 1178 REJ09B0403 0100...
Page 116: ...Section 3 MCU Operating Modes Rev 1 00 Mar 12 2008 Page 68 of 1178 REJ09B0403 0100...
Page 152: ...Section 5 Interrupt Controller Rev 1 00 Mar 12 2008 Page 104 of 1178 REJ09B0403 0100...
Page 206: ...Section 6 Bus Controller BSC Rev 1 00 Mar 12 2008 Page 158 of 1178 REJ09B0403 0100...
Page 420: ...Section 9 14 Bit PWM Timer PWMX Rev 1 00 Mar 12 2008 Page 372 of 1178 REJ09B0403 0100...
Page 476: ...Section 12 Watchdog Timer WDT Rev 1 00 Mar 12 2008 Page 428 of 1178 REJ09B0403 0100...
Page 552: ...Section 14 CRC Operation Circuit CRC Rev 1 00 Mar 12 2008 Page 504 of 1178 REJ09B0403 0100...
Page 712: ...Section 18 I2 C Bus Interface IIC Rev 1 00 Mar 12 2008 Page 664 of 1178 REJ09B0403 0100...
Page 804: ...Section 19 LPC Interface LPC Rev 1 00 Mar 12 2008 Page 756 of 1178 REJ09B0403 0100...
Page 838: ...Section 20 Ethernet Controller EtherC Rev 1 00 Mar 12 2008 Page 790 of 1178 REJ09B0403 0100...
Page 964: ...Section 24 RAM Rev 1 00 Mar 12 2008 Page 916 of 1178 REJ09B0403 0100...
Page 1066: ...Section 25 Flash Memory Rev 1 00 Mar 12 2008 Page 1018 of 1178 REJ09B0403 0100...
Page 1098: ...Section 26 Boundary Scan JTAG Rev 1 00 Mar 12 2008 Page 1050 of 1178 REJ09B0403 0100...
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