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10.4 Registers of External Interrupt Circuit 1
Table 10.4-1 Functions of Bits of External Interrupt Control Register 1 (EIC1)
Bit name
Function
bit7
EIR1: External
interrupt request flag
bit 1
When a signal with an edge or edges corresponding to edge
polarity selected by edge polarity selection bits (SL11, SL10) is
input to INT11 external interrupt pin, this bit is set to 1.
When this bit and interrupt request enable bit 1 (EIE1) are 1, the
interrupt request is output.
Writing 0 clears this bit; writing 1 does not affect this bit (no
change).
bit6
bit5
SL11, SL10: Edge
polarity selection
bits 1
These bits are used to select the polarity of an edge or edges of a
signal pulse that triggers an interrupt when the signal is input to
INT11 external interrupt pin.
When these bits provide a value of "00B," edge detection is not
performed and interrupt requests are not generated.
These bits may specify "01B", indicating a rising edge, "10B", a
falling edge, or "11B", both edges to be detected.
Note:
If an edge is selected while edge detection is OFF, edge detection
may be performed unconditionally. Always clear the EIR0 bit after
selecting an edge
bit4
EIE1: Interrupt
request enable bit 1
This bit enables or disables interrupt request outputs to CPU. When
this bit and external interrupt request flag bit 1 (EIR1) are 1, the
interrupt request is output.
Tips:
When using the external interrupt pin, write 0 for bit 5 of the port
data direction register (DDR3) so that the pin serves inputs only.
Regardless of the interrupt request enable bit state, the state of
the external interrupt pin can be read directly from the port data
register (PDR3).
bit3
EIR0: External
interrupt request flag
bit 0
When a signal with an edge or edges corresponding to edge
polarity selected by edge polarity selection bits (SL01, SL00) is
input to INT10 external interrupt pin, this bit is set to 1.
When this bit and interrupt request enable bit 0 (EIE0) are 1, the
interrupt request is output.
Writing 0 clears this bit, and writing 1 does not affect this bit.
bit2
bit1
SL01, SL00: Edge
polarity selection
bits 0
These bits are used to select the polarity of an edge or edges of a
signal pulse that triggers an interrupt when the signal is input to
the INT10 external interrupt pin.
When these bits provide a value of "00B", edge detection is not
performed and interrupt requests are not generated.
These bits may specify "01B", indicating a rising edge, "10B", a
falling edge, or "11B", both edges to be detected.
Note:
If edge is selected when edge detection is OFF, edge detection
may be performed unconditionally. Always clear the EIR0 bit after
selecting an edge.