SH7055S Datasheet, PDF (895/1002 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7000 Series

24.4.3 Software Standby Mode Application Example
This example describes a transition to software standby mode on the falling edge of the NMI
signal, and cancellation on the rising edge of the NMI signal. The timing is shown in figure 24.3.
When the NMI pin is changed from high to low level while the NMI edge select bit (NMIE) in
ICR is set to 0 (falling edge detection), the NMI interrupt is accepted. When the NMIE bit is set to
1 (rising edge detection) by the NMI exception service routine, the software standby bit (SSBY) in
SBYCR is set to 1, and a SLEEP instruction is executed, software standby mode is entered.
Thereafter, software standby mode is canceled when the NMI pin is changed from low to high
level.
Oscillator
CK
NMI pin
NMIE bit
SSBY bit
SH7055 Program
state execution
NMI
exception
processing
Exception
service routine
Software
standby mode
Oscillation
settling time
NMI exception
processing
Figure 24.3 Software Standby Mode NMI Timing (Application Example)
Rev.2.0, 07/03, page 857 of 960