HD6433937 Datasheet, PDF (93/521 Pages) Hitachi Semiconductor – Hardware Manual

3.4.2 Notes on Rewriting Port Mode Registers
When a port mode register is rewritten to switch the functions of external interrupt pins, the
following points should be observed.
When an external interrupt pin function is switched by rewriting the port mode register that
controls pins IRQ₄ to IRQ₁, WKP₇ to WKP₀, the interrupt request flag may be set to 1 at the time
the pin function is switched, even if no valid interrupt is input at the pin. Be sure to clear the
interrupt request flag to 0 after switching pin functions. Similarly, when the pin function is
switched by rewriting the port mode register that controls IRQ₀, the interrupt request flag may be
set to 1 at the time the pin function is switched, even if no valid interrupt is input. Therefore, be
sure to clear the interrupt request flag to 0 after switching the pin function. Table 3-5 shows the
conditions under which interrupt request flags are set to 1 in this way.
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