Interrupt Sources; External Interrupts - Hitachi H8/3022 Hardware Manual

5.3 Interrupt Sources

The interrupt sources include external interrupts (NMI, IRQ
internal interrupts.

5.3.1 External Interrupts

There are five external interrupts: NMI, and IRQ
IRQ , can be used to exit software standby mode.
1
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 , IRQ , IRQ , IRQ
5 4 1
IRQ , IRQ , IRQ
. The IRQ
4 1 0
• ISCR settings can select whether an interrupt is requested by the low level of the input at pins
IRQ , IRQ , IRQ
5 4
• IER settings can enable or disable the IRQ
Interrupt priority levels can be assigned by three bits in IPRA (IPRA7, IPRA6, and IPRA4).
• The status of IRQ
be cleared to 0 by software.
Figure 5-2 shows a block diagram of interrupts IRQ
IRQn input
Note: n = 5, 4, 1 and 0
Figure 5-2 Block Diagram of Interrupts IRQ
90
Interrupts: These interrupts are requested by input signals at pins IRQ
0
, IRQ , IRQ
5 4
, IRQ
, or by the falling edge.
1 0
, IRQ , IRQ , IRQ
5 4 1
IRQnSC
Edge/level
sense circuit
5
, IRQ , IRQ
5 4
, IRQ interrupts have the following features.
1 0
, IRQ , IRQ , IRQ
5 4 1
interrupt requests is indicated in ISR. The ISR flags can
0
, IRQ , IRQ
5 4
IRQnF
S
R
Clear signal
, IRQ , IRQ and IRQ
4 1
, and IRQ . Of these, NMI, IRQ
1 0
interrupts.
0
, IRQ .
1 0
IRQnE
Q
, IRQ , IRQ , and IRQ
5 4 1
) and 25
0
,
0
,
5
IRQn interrupt
request
0