R8C/1A Group, R8C/1B Group
12. Interrupts
Rev.1.30
Dec 08, 2006
Page 96 of 315
REJ09B0252-0130
12.3
Key Input Interrupt
A key input interrupt request is generated by one of the input edges of pins K10 to K13. The key input interrupt can
be used as a key-on wake-up function to exit wait or stop mode.
The KIiEN (i = 0 to 3) bit in the KIEN register can select whether or not the pins are used as KIi input. The KIiPL
bit in the KIEN register can select the input polarity.
When “L” is input to the KIi pin, which sets the KIiPL bit to 0 (falling edge), input to the other pins K10 to K13 is
not detected as interrupts. Also, when “H” is input to the KIi pin, which sets the KIiPL bit to 1 (rising edge), input
to the other pins K10 to K13 is not detected as interrupts.
Figure 12.17 shows a Block Diagram of Key Input Interrupt.
Figure 12.17
Block Diagram of Key Input Interrupt
KI3
Pull-up
transistor
KI2
Pull-up
transistor
KI3PL = 0
KI3PL = 1
PD1_3 bit
KI3EN bit
PU02 bit in PUR0 register
PD1_3 bit in PD1 register
KUPIC register
Interrupt control
circuit
Key input interrupt
request
KI2PL = 0
KI2PL = 1
PD1_2 bit
KI2EN bit
KI1
Pull-up
transistor
KI1PL = 0
KI1PL = 1
PD1_1 bit
KI1EN bit
KI0
Pull-up
transistor
KI0PL = 0
KI0PL = 1
PD1_0 bit
KI0EN bit
KI0EN, KI1EN, KI2EN, KI3EN,
KI0PL, KI1PL, KI2PL, KI3PL: Bits in KIEN register
PD1_0, PD1_1, PD1_2, PD1_3: Bits in PD1 register
