Figure 24.3 Software Standby Mode Application Example - Renesas H8S Series Hardware Manual

Figure 24.3 shows an example in which a transition is made to software standby mode at the
falling edge of the NMI pin, and software standby mode is cleared at the rising edge of the NMI
pin.
In this example, an NMI interrupt is accepted with the NMIEG bit in SYSCR cleared to 0 (falling
edge specification), then the NMIEG bit is set to 1 (rising edge specification), the SSBY bit is set
to 1, and a SLEEP instruction is executed, causing a transition to software standby mode.
Software standby mode is then cleared at the rising edge of the NMI pin.
Oscillator
φ
NMI
NMIEG
SSBY

Figure 24.3 Software Standby Mode Application Example

NMI exception Software standby mode
handling (power-down mode)
NMIEG = 1
SSBY = 1
SLEEP instruction
Section 24 Power-Down Modes
NMI exception
Oscillation
handling
stabilization
time t
OSC2
Rev. 3.00 Jul. 14, 2005 Page 873 of 986
REJ09B0098-0300