HD6432633 Datasheet, PDF (1056/1453 Pages) Renesas Technology Corp – Series of Microcomputers (MCUs: microcomputer units)

(1) Exiting Software Standby Mode with an Interrupt
When an NMI or IRQ0 to IRQ7 interrupt request signal is input, clock oscillation starts, and
after the elapse of the time set in bits STS2 to STS0 in SBYCR, stable clocks are supplied to
the entire chip, software standby mode is exited, and interrupt exception handling is started.
When exiting software standby mode with an IRQ0 to IRQ7 interrupt, set the corresponding
enable bit to 1 and ensure that no interrupt with a higher priority than interrupts IRQ0 to IRQ7
is generated. Software standby mode cannot be exited if the interrupt has been masked on the
CPU side or has been designated as a DTC activation source.
(2) Exiting Software Standby Mode by RES or MRES Pins
When the RES pin or MRES pin is driven low, clock oscillation is started. At the same time as
clock oscillation starts, clocks are supplied to the entire chip. Note that the RES pin or MRES
pin must be held low until clock oscillation stabilizes. When the RES pin or MRES pin goes
high, the CPU begins reset exception handling.
(3) Exiting Software Standby Mode by STBY Pin
When the STBY pin is driven low, a transition is made to hardware standby mode.
24.6.3 Setting Oscillation Stabilization Time after Clearing Software Standby Mode
Bits STS2 to STS0 in SBYCR should be set as described below.
Using a Crystal Oscillator: Set bits STS2 to STS0 so that the standby time is at least 8 ms (the
oscillation stabilization time).
Table 24-5 shows the standby times for different operating frequencies and settings of bits STS2
to STS0.
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