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CHAPTER 11 EXTERNAL INTERRUPT CIRCUIT 2 (LEVEL)
Table 11.4-2 Functions of the Bits of the External Interrupt 2 Control Register (EIE2)
Bit name Function
bit7
to
bit0
IE27 to IE20:
External interrupt
input enable bits
• These bits enable or disable the interrupt inputs to external
interrupt pins INT20
to INT27.
• When one of these bits is set to "1", the corresponding external
interrupt pin functions as an external interrupt input pin and
accepts external interrupt inputs.
• When the bit is set to "0", the corresponding pin functions as a
general-purpose port, but does not accept external interrupt
inputs.
Notes:
• When using a pin as an external interrupt pin, write "0" in the
port 0 data direction register (DDR0) in the bit corresponding to
the pin so that the pin serves inputs only.
• Regardless of the external interrupt input enable bit state, the
state of the external interrupt pin can be read directly from the
port 0 data register (PDR0). For pins INT20
to INT23,
furthermore, write "0" into A/D enable register (ADEN) in the
bits corresponding to the pins to use the pins for external
interrupt inputs.