M16C62_M Datasheet, PDF (481/615 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

Key-Input Interrupt
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
2.13.2 Operation of Key-Input Interrupt
The following is an operation of key-input interrupt. Figure 2.13.3 shows an example of a circuit that uses
the key-input interrupt, Figure 2.13.4 shows an example of operation of key-input interrupt, and Figure
2.13.5 shows the setting procedure of key-input interrupt.
Operation (1) Set the direction register of the ports to be changed to key-input interrupt pins to input, and set
the pull-up function.
(2) Setting the key-input interrupt control register and setting the interrupt enable flag makes the
interrupt-enabled state ready.
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(3) If a falling edge is input to either KI0 through KI3, the key-input interrupt request bit goes to “1”.
P100
P101
P102
P103
P104 / KI0
P105 / KI1
P106 / KI2
P107 / KI3
VREF
I/O port
Figure 2.13.3. Example of circuit using the key-input interrupt
(1) Enter to stop mode
(2) Cancel stop mode
(3) Key scan
(4) Enter to stop mode
Key matrix scan
P100 output
P101 output
P102 output
P103 output
P104 to P107
input
Key input
Key input
interrupt processing
Key OFF
Key ON
Key OFF
Key ON
Figure 2.13.4. Example of operation of key-input interrupt
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