Fujitsu F2MC-8L F202RA Hardware Manual page 252

CHAPTER 10 EXTERNAL INTERRUPT CIRCUIT 1 (EDGE)
Table 10.4-2 Explanation of Functions of Each Bit in External Interrupt Control Register 2 (EIC2)
Bit name
bit7
to Unused bits
bit4
EIR2:
bit3 External interrupt
request flag bit 2
SL21, SL20:
bit2
Edge polarity selection
bit1
bits 2
EIE2:
bit0 Interrupt request
enable bit 2
236
• Bit value is undefined when being read.
• Written value does not affect other operations.
• When a signal with an edge or edges corresponding to edge polarity
selected by edge polarity selection bits 2 (SL21, SL20) is input to the
INT12 external interrupt pin, this bit is set to "1".
• When this bit and interrupt request enable bit 2 (EIE2) are "1", the
interrupt request is output.
• Writing "0" clears this bit, and writing "1" does not affect this bit (no
change).
• 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 INT12
external interrupt pin.
• When these bits provide a value of "00
performed and interrupt requests are not generated.
• These bits may specify "01
edge, or "11 ", both edges to be detected.
B
Note:
If edge is selected while edge detection is OFF, edge detection may be
performed unconditionally. Always clear EIR2 bit after selecting an edge.
This bit enables or disables interrupt request outputs to the CPU. When this
bit and external interrupt request flag bit 2 (EIR2) are "1", the interrupt
request is output.
Notes:
• When using the external interrupt pin, write "0" for bit6 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 external
interrupt pin can be read directly from the port data register (PDR3).
Function
", edge detection is not
B
", indicating a rising edge, "10
B
", a falling
B