SH7727 Datasheet, PDF(317/1109 Page) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

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SH7727 Datasheet, PDF (317/1109 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

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Section 9 Power-Down Modes and Software Reset

9.4.2 Canceling Standby Mode

Standby mode is canceled by an interrupt (NMI, IRQ, IRL, on-chip supporting module interrupt or

PINT) or a reset.

Canceling with an Interrupt: The on-chip WDT can be used for hot starts. When the chip detects

an NMI, IRL, IRQ, PINT*1, or on-chip supporting module (except the interval timer)*2 interrupt,

the clock will be supplied to the entire chip and standby mode canceled after the time set in the

WDTâs timer control/status register has elapsed. The STATUS1 and STATUS0 pins both go low.

Interrupt exception handling then begins and a code corresponding to the interrupt source is set in

the INTEVT and INTEVT2 registers. After branching to the interrupt processing routine occurs,

clear the STBY bit in the STBCR register. The WTCNT stops automatically. If the STBY bit is

not cleared, WTCNT continues operation and transits to the standby mode*3 when it reaches Hâ80.

This function prevents the data from being destroyed due to a rising voltage under an unstable

power supply. Interrupts are accepted during standby mode even when the BL bit in the SR

register is 1. If necessary, save SPC and SSR in the stack before executing the SLEEP instruction.

Immediately after an interrupt is detected, the phase of the clock output of the CKIO and CKIO2

pin may be unstable, until the standby mode is canceled. The canceling condition is that the

interrupt request level (IRQ, IRL, or on-chip supporting module interrupt) is higher than the mask

level in the I3 to I0 bits in the SR register.

Notes: 1. When the RTC is being used, standby mode can be canceled using IRL3 to IRL0, IRQ4

to IRQ0 or PINT0 to PINT5.

2. Standby mode can be canceled with an RTC or TMU (only when running on the RTC

clock) interrupt.

3. Use a power-on reset to cancel standby mode.

Operation is not guaranteed in the case of a manual reset or interrupt input.

Rev. 5.00 Dec 12, 2005 page 245 of 1034

REJ09B0254-0500

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