Interrupt Sources; External Interrupts - Hitachi H8/3006 Hardware Manual

5.3

Interrupt Sources

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.
Interrupts: These interrupts are requested by input signals at pins IRQ
IRQ to 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
to 0 by software.
Figure 5-2 shows a block diagram of interrupts IRQ
IRQn
input
Note: n = 5 to 0
Figure 5-2 Block Diagram of Interrupts IRQ
to IRQ interrupt requests is indicated in ISR. The ISR flags can be cleared
0 5
IRQnSC
Edge/level
sense circuit
to IRQ
0
to IRQ . Of these, NMI, IRQ
0 5
to IRQ interrupts. Interrupt priority levels can be
0 5
to IRQ .
0 5
IRQnF
S Q
R
Clear signal
) and 36 internal interrupts.
5
, IRQ , and
0 1
to IRQ
0
IRQnE
IRQn interrupt
request
to IRQ
0 5
.
5
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