26-1
Seiko Epson Corporation
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
26.
Appendix
Appendix A
Power Saving
Current consumption will vary dramatically, depending on CPU operating mode, operation clock
frequency, peripheral circuits being operated, and V
D1
regulator operating mode. Listed below are the
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
Current
consumption
V
D1
OSC1
IOSC/
OSC3/
EXOSC
RTCA
CPU
Current consumption
listed in electrical
characteristics
Standby
↑
Low
High
↓
Economy
OFF
OFF
OFF
SLEEP
I
SLP1-2
Clock counting
ON
ON
SLEEP with OSC1SLPC
I
SLP3-4
Low-speed processing
OSC1 RUN
I
RUN4
–
5
Peripheral circuit operations
Normal
ON
SLEEP or HALT
I
HALT4-5
High-speed processing
IOSC/OSC3/EXOSC
RUN
I
RUN1
–
3, 6-7
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 sh
own 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
SLP
that is listed in
“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.
Summary of Contents for S1C31D50
Page 461: ...25 1 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 25 Package TQFP12 48PIN ...
Page 462: ...25 2 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 QFP13 64PIN ...
Page 463: ...25 3 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 TQFP14 80PIN ...
Page 464: ...25 4 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 QFP15 100PIN ...