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26. Appendix
Appendix A
Current consumption will vary dramatically, depending on CPU operating mode, operation clock
frequency, peripheral circuits being operated, and V
control methods for saving power.
A.1 Operating Status Configuration Examples for Power Saving
Table A.1.1 lists typical examples of operating status configuration with consideration given to power
saving.
Table A.1.1 Typical Operating Status Configuration Examples
Operating status
configuration
Standby
Clock counting
Low-speed processing
Peripheral circuit operations
High-speed processing
If the current consumption order by the operating status configuration shown in Table A.1.1 is different
from one that is listed in "Electrical Characteristics," check the settings shown below.
PWGACTL.REGMODE[1:0] bits of the power generator
If the PWGACTL.REGMODE[1:0] bits of the power generator are 0x2 (normal mode) when the CPU
enters SLEEP mode, current consumption in SLEEP mode will be larger than I
"Electrical Characteristics." Set the PWGACTL.REGMODE[1:0] bits to 0x3 (economy mode) or 0x0
(automatic mode) before placing the CPU into SLEEP mode.
CLGOSC.IOSCSLPC/OSC1SLPC/OSC3SLPC/EXOSCSLPC bits of the clock generator
Setting the CLGOSC.IOSCSLPC, OSC1SLPC, OSC3SLPC, or EXOSCSLPC bit of the clock generator to
0 disables the oscillator circuit stop control when the CPU enters SLEEP mode. To stop the
oscillator circuits
during SLEEP mode, set these bits to 1.
MODEN bits of the peripheral circuits
Setting the MODEN bit of each peripheral circuit to 1 starts supplying the operating clock enabling
the peripheral circuit to operate. To reduce current consumption, set the MODEN bits of
unnecessary peripheral circuits to 0. Note that the real-time clock has no MODEN bit, therefore,
current consumption does not vary if it is counting or idle.
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
Power Saving
Current
V
OSC1
D1
consumption
OFF
↑
Economy
Low
ON
Normal
High
↓
Seiko Epson Corporation
regulator operating mode. Listed below are the
D1
IOSC/
OSC3/
RTCA
CPU
EXOSC
OFF
SLEEP
SLEEP with OSC1SLPC
OFF
OSC1 RUN
ON
SLEEP or HALT
ON
IOSC/OSC3/EXOSC
RUN
Current consumption
listed in electrical
characteristics
I
SLP1-2
I
SLP3-4
I
RUN4–5
I
HALT4-5
I
RUN1–3, 6-7
that is listed in
SLP
26-1
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