Interrupt Sources; External Interrupts - Hitachi H8/3048 Hardware Manual

5.3 Interrupt Sources

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The interrupt sources include external interrupts (NMI, IRQ

5.3.1 External Interrupts

There are seven external interrupts: NMI, and IRQ
IRQ can be used to exit software standby mode.
2
NMI: NMI is the highest-priority interrupt and is always accepted, regardless of the states of the
I and UI bits in CCR. The NMIEG bit in SYSCR selects whether an interrupt is requested by the
rising or falling edge of the input at the NMI pin. NMI interrupt exception handling has vector
number 7.
IRQ to IRQ Interrupts: These interrupts are requested by input signals at pins IRQ
0 5
The IRQ to IRQ interrupts have the following features.
0 5
• ISCR settings can select whether an interrupt is requested by the low level of the input at pins
IRQ to IRQ , or by the falling edge.
0 5
• IER settings can enable or disable the IRQ
assigned by four bits in IPRA (IPRA7 to IPRA4).
• The status of IRQ
cleared to 0 by software.
Figure 5-2 shows a block diagram of interrupts IRQ
IRQn
input
Note: n = 5 to 0
to IRQ interrupt requests is indicated in ISR. The ISR flags can be
0 5
IRQnSC
Edge/level
sense circuit
Figure 5-2 Block Diagram of Interrupts IRQ
to IRQ ) and 30 internal interrupts.
0 5
to IRQ . Of these, NMI, IRQ
0 5
to IRQ interrupts. Interrupt priority levels can be
0 5
to IRQ .
0 5
IRQnE
IRQnF
S Q
R
Clear signal
to IRQ
0
95
, IRQ , and
0 1
to IRQ .
0 5
IRQn interrupt
request
5