M38045F2HKP datasheet(279/387 Pages) RENESAS

279 / 387 page

2-155

APPLICATION

2.12 Standby function

Rev.1.00 Jan 14, 2005

REJ09B0212-0100Z

3804 Group (Spec.H)

sRestoration by interrupt request

In the wait mode, the occurrence of an interrupt request releases the wait mode and supply of the

internal clock

φ to the CPU is started. At the same time, the interrupt request used for restoration

is accepted, so the interrupt processing routine is executed.

However, when using an interrupt request for restoration from the wait mode, in order to enable the

selected interrupt, you must execute the STP instruction after setting the following conditions.

[Necessary register setting]

➀ Interrupt disable flag I = “0” (interrupt enabled)

➁ Interrupt request bit of interrupt source to be used for restoration = “0” (no interrupt request issued)

➂ Interrupt enable bit of interrupt source to be used for restoration = “1” (interrupts enabled)

For more details concerning interrupts, refer to “2.2 Interrupts”.

(3)

Notes on wait mode

sClock restoration

If the wait mode is released by a reset when XCIN is set as the system clock and XIN oscillation is

stopped during execution of the WIT instruction, XCIN oscillation stops, XIN oscillations starts, and

XIN is set as the system clock.

In the above case, the RESET pin should be held at “L” until the oscillation is stabilized.

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