Section 22 Power-Down Modes
Rev. 5.00 May 29, 2006 page 574 of 698
REJ09B0146-0500
22.3.2
Software Standby Mode
Transition to Software Standby Mode
To enter standby mode, set the STBY bit to 1 in STBCR, then execute the SLEEP instruction. The
chip moves from the program execution state to software standby mode. In software standby
mode, power consumption is greatly reduced by halting not only the CPU, but the clock and on-
chip supporting modules as well. The clock output from the CKIO pin also halts. CPU and cache
register contents are held, but some on-chip supporting modules are initialized. Table 22.3 lists the
states of registers in software standby mode.
Table 22.3
Register States in Software Standby Mode
Module
Registers Initialized
Registers Retaining Data
Interrupt controller (INTC)
—
All registers
On-chip clock pulse generator
(CPG)
—
All registers
User Break controller (UBC)
—
All registers
Bus state controller (BSC)
—
All registers
Timer unit (TMU)
TSTR register
Registers other than TSTR
Realtime clock (RTC)
—
All registers
A/D converter (ADC)
All registers
—
D/A converter (DAC)
—
All registers
The procedure for moving to software standby mode is as follows:
1. Clear the TME bit in the WDT's timer control register (WTCSR) to 0 to stop the WDT. Set the
WDT's timer counter (WTCNT) and the CKS2 to CKS0 bits of the WTCSR register to
appropriate values to secure the specified oscillation settling time.
2. After the STBY bit in the STBCR register is set to 1, a SLEEP instruction is executed.
3. Software standby mode is entered and the clocks within the chip are halted. The STATUS1 pin
output goes low and the STATUS0 pin output goes high.
Canceling Software Standby Mode
Standby mode is canceled by an interrupt (NMI, IRQ*
1
, IRL*
1
, or on-chip supporting module)*
2
or
a reset.
Summary of Contents for SH7706 Series
Page 8: ...Rev 5 00 May 29 2006 page viii of xlviii ...
Page 160: ...Section 5 Cache Rev 5 00 May 29 2006 page 112 of 698 REJ09B0146 0500 ...
Page 370: ...Section 11 Watchdog Timer WDT Rev 5 00 May 29 2006 page 322 of 698 REJ09B0146 0500 ...
Page 554: ...Section 17 Pin Function Controller PFC Rev 5 00 May 29 2006 page 506 of 698 REJ09B0146 0500 ...
Page 576: ...Section 18 I O Ports Rev 5 00 May 29 2006 page 528 of 698 REJ09B0146 0500 ...
Page 746: ...Index Rev 5 00 May 29 2006 page 698 of 698 REJ09B0146 0500 ...
Page 749: ...SH7706 Group Hardware Manual ...