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Table 9.2
I/O-1/IRQ and I/O-2/IRQ Pin States
Operating Mode
Normal operation
Sleep mode
Note: When sleep mode is entered or canceled, the output from the I/O ports will collide with the
IRQ input. To avoid this, set DDR to 0 to use the pins as I/O input ports before executing a
SLEEP instruction.
These pins become interrupt input pins in sleep mode regardless of the DDR value, and the falling
edge of the logical OR of these signals is handled as an external interrupt request signal to the
CPU. Therefore, either one of these pins, or both can be used as interrupt input.
An input pull-up MOS is connected to each of I/O-1/IRQ and I/O-2/IRQ pins to avoid an
erroneous interrupt request when the input is at high-impedance. The input pull-up MOS's are
always switched on, even in sleep mode. To reduce the input pull-up MOS current, input a high
level to the I/O-1/IRQ and I/O-2/IRQ pins in sleep mode, except when requesting an interrupt. If
only one of the pins is used, the one that is not used must be left open.
DDR Value
0 (Initial Value)
Input port
IRQ input pin
1
Output port
Must not be set*
101
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