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Section 33 Power-Down Modes
Page 1810 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
33.3.3 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 33.1.
When the NMI pin is changed from high to low level while the NMI edge select bit (NMIE) in the
interrupt control register 0 (ICR0) 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 STBY and DEEP bits in STBCR1 are set to 1 and 0 respectively, 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.
CK
NMI pin
NMIE bit
STBY bit
LSI state
Oscillator
Program
execution
NMI
exception
handling
NMI exception
handling
Exception
service routine
Software
standby mode
Oscillation
settling time
Figure 33.1 NMI Timing in Software Standby Mode (Application Example)