Operating Description Of Interrupt Pin Selection Circuit - Fujitsu F2MC-8FX Hardware Manual

19.5

Operating Description of Interrupt Pin Selection Circuit

The interrupt pins are selected by setting WICR (interrupt pin selection circuit control
register).
Operation of Interrupt Pin Selection Circuit
The WICR (interrupt pin selection circuit control register) setting is used to select the input pins to be
inputted to INT00 of the external interrupt circuit (channel 0). Shown below is the setup procedure for the
interrupt pin selection circuit and external interrupt circuit (channel 0), which must be followed when
selecting the TRG0 pin as an interrupt pin.
1) Write "0" to the corresponding bit in the port direction register (DDR) to set the pin as an input.
2) Select the TRG0 pin as an interrupt input pin in WICR (interrupt pin selection circuit control register).
(Write "01
of the external interrupt circuit, the operation of the external interrupt circuit is disabled.)
3) Enable the operation of INT00 of the external interrupt circuit (channel 0).
(Set the SL01 and SL00 bits of the EIC00 register to any value other than "00
circuit to select the valid edge. Also write "1" to the EIE0 bit to enable interrupts).
4) The subsequent interrupt operation is the same as for the external interrupt circuit.
• When a reset is released, WICR (interrupt pin selection circuit control register) is initialized to "40
and the INT00 bit is selected as the only available interrupt pin. Update the value of this register before
enabling the operation of the external interrupt circuit, when using any pins other than the INT00 pin as
external interrupt pins.
Note:
If more than one interrupt pin are selected in WICR (interrupt pin selection circuit control register)
simultaneously, an input to INT00 (channel 0) of the external interrupt circuit is treated as "H" if any
of the selected input signals is "H". (It becomes "OR" of the signals inputted to the selected pins.)
" to the WICR register. At this point, after writing "0" in the EIE0 bit of the EIC00 register
H
CHAPTER 19 INTERRUPT PIN SELECTION CIRCUIT
" in the external interrupt
B
H
325
"