SH7670 Datasheet, PDF (418/1292 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7670 Series

Section 11 Power-Down Modes
11.3.3 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 11.1.
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 STBY bit in STBCR 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
STBY bit
LSI state
Program
execution
NMI
exception
handling
Exception
service routine
Software
standby mode
Oscillation
settling time
NMI exception
handling
Figure 11.1 NMI Timing in Software Standby Mode (Application Example)
Rev. 1.00 Nov. 14, 2007 Page 392 of 1262
REJ09B0437-0100