APPENDIX B POWER SAVING
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
AP-B-3
3. Resuming by a peripheral or a debug interrupt (issuing an ICD forced break)
The CPU resumes operating by occurrence of a cause of interrupt in a peripheral whose interrupt is enabled.
If the IE flag in the CPU has been set to 0, the CPU does not accept the interrupt request and starts executing
the instructions that follow the halt instruction. If the IE flag has been set to 1, the CPU executes the interrupt
handler.
Battery backup mode
• Turning the system power (LV
DD
, HV
DD
, AV
DD
, PLLV
DD
) off
If the system uses separated the system power and RTCV
DD
power sources, it is possible to operate only the
RTCV
DD
system circuits (RTC, OSC1, and BBRAM) with the system power turned off to reduce current
consumption. Turning the system power off reduces leakage current that cannot be reduced in SLEEP mode.
The #STBY and WAKEUP pins that have been provided in the RTC module are used for controlling this
function. Refer to the “Real-Time Clock (RTC)” chapter for more information on the control.
Note: The battery backup mode can help reduce current consumption when many parts are used in the
external circuit or if the HV
DD
/AV
DD
system circuits will be deactivated for a relatively long time.
Depending on the system configuration, the SLEEP mode may be efficient for saving power. Take
these conditions into consideration at the system design stage.