
10. Interrupts
10.8
NMI Interrupt
The NMI interrupt occurs when a signal applied to the P8_5/NMI pin changes from high level (“H”) to low level
(“L”). The NMI interrupt is non-maskable. Although the P8_5/NMI pin is used as the NMI interrupt input pin, the
P8_5 bit in the P8 register indicates input level for this pin. When the NMI interrupt is not used, connect the NMI
pin to VCC via a resistor (pull-up).
10.9
Key Input Interrupt
Key input interrupt request is generated when any of the signals applied to pins P10_4 to P10_7 in input mode is at
the falling edge. The key input interrupt can also be used as key-on wake-up function to exit wait or stop mode. To
use the key input interrupt, do not use pins P10_4 to P10_7 as A/D input ports.
Figure 10.14 shows a block diagram
of the key input interrupt. When an “L” signal is applied to one of these pins in input mode, signals applied to the
rest of the pins are not detected as an interrupt request signal.
When the PSC_7 bit in the PSC register is set to 1 (key input interrupt disabled), no key input interrupt occurs
regardless of interrupt control register settings. When the PSC_7 bit is set to 1, input to ports are disabled even if
the Port Pi Direction Register is set for input.
Figure 10.14
Key Input Interrupt
Key input
interrupt
request
P10_7/KI3
PU31 bit
PD10_7 bit
Pull-up
transistor
Pull-up
transistor
Pull-up
transistor
Pull-up
transistor
PD10_7 bit
PD10_6 bit
PD10_5 bit
PD10_4 bit
P10_6/KI2
P10_5/KI1
P10_4/KI0
Interrupt control
circuit
KUPIC register
PSC_7 bit
PU31: Bit in the PUR3 register
PD10_4 to PD10_7: Bits in the PD10 register
PSC_7: Bit in the PSC register