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10.5 External Interrupt Circuit Interrupts
10.5 External Interrupt Circuit Interrupts
As an interrupt source of the external interrupt circuit, the detection of the specified
edge of a signal input into the external interrupt pin is available.
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Interrupts when the External Interrupt Circuit is Operating
If the specified edge of the external interrupt input is detected, "1" is set to the corresponding
external interrupt request flag bit (EIC1: EIR0 to EIR1/EIC2: EIR2 to EIR3). At this time, if the
corresponding interrupt request enable bit is set (EIC1: EIE0 to EIE1=1/EIC2: EIE2 to EIE3=1),
an interrupt request (IRQ0, IRQ1) to CPU is issued.
The following table lists the correspondence of the interrupt requests (IRQ0 to IRQ1).
If no external interrupt is used to return from the stop mode, set "00" to the edge polarity bits
and "0" to the interrupt enable bit.
Note:
To allow interrupts (EIE0 to EIE2=1) after releasing a reset, clear (EIR0 to EIR2=0) the
external interrupt request flag bit at the same time.
It is not possible to return from interrupt processing if the external interrupt request flag bit is
"1" and the interrupt request enable bit is set. The external interrupt request flag bit in
interrupt processing routines must be cleared.
The release of the stop mode by an interrupt is possible only in the external interrupt circuit.
If the interrupt request enable bit is changed from prohibition to permission (0 --> 1), an interrupt
occurs immediately.
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Register and Vector Table Related to Interrupts of the External Interrupt Circuit
For interrupt operations, see Section 3.4.2 "Interrupt Processing".
Interrupt request (INT)
Interrupt request to CPU
INT0
IRQ0
INT1
INT2
IRQ1
INT3
Table 10.5-1 Register and Vector Table Related to Interrupts of the External Interrupt
Circuit
Interrupt
name
Interrupt level setting register
Vector table address
Register
Bit to be set
Upper
Lower
IRQ0
ILR1 (007B
H
)
L01 (bit 1)
L00 (bit 0)
FFFA
H
FFFB
H
IRQ1
ILR1 (007B
H
)
L11 (bit 3)
L10 (bit 2)
FFF8
H
FFF9
H