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2.1.4. V
Regulator Voltage Mode
D1
The V
regulator supports two voltage modes, mode0 and mode1.
D1
When the IC runs with a low-speed clock, setting the V
consumption.
When the voltage mode is switched, the system clock source automatically stops operating and it
resumes operating after the voltage has stabilized. Table 2.1.4.1 shows the stop period of the system
clock.
Table 2.1.4.1 System Clock Stop Period After Switching Voltage Mode
System clock
IOSC
OSC1
Procedure to switch from mode0 to mode1
1. Set the MODEN bits of the peripheral circuits to 0.
2. Write 0x0096 to the SYSPROT.PROT[15:0] bits.
3. Switch the system clock to a low-speed clock
4. Stop OSC3 and EXOSC.
5. Configure the following PWGACTL register bits.
Set the PWGACTL.REGSEL bit to 0.
-
Set the PWGACTL.REGDIS bit to 1.
-
Set the PWGACTL.REGMODE[1:0] bits to 0x2.
-
6. Configure the following PWGACTL register bits after the system clock supply has resumed.
Set the PWGACTL.REGDIS bit to 0.
-
Set the PWGACTL.REGMODE[1:0] bits to 0x0.
-
7. Write a value other than 0x0096 to the SYSPROT.PROT[15:0] bits.
Procedure to switch from mode1 to mode0
1. Set the MODEN bits of the peripheral circuits to 0.
2. Write 0x0096 to the SYSPROT.PROT[15:0] bits.
3. Configure the following PWGACTL register bits.
Set the PWGACTL.REGSEL bit to 1.
-
Set the PWGACTL.REGMODE[1:0] bits to 0x2.
-
4. Set the PWGACTL.REGMODE[1:0] bits to 0x0after the system clock supply has resumed.
5. Switch the system clock to a high-speed clock.
6. Write a value other than 0x0096 to the SYSPROT.PROT[15:0] bits.
Notes:
After the voltage mode has been switched, correct the RTC, as the RTC operating clock
•
is also stopped for the period set using the CLGOSC1.OSC1WT[1:0] bits.
Always use the IC in mode0 when V
•
If you use two voltage mode, set mode1 before sleep or halt mode.
•
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
regulator into mode1 reduces power
D1
Stop period
4,096 cycles
Number of cycles set using the CLGOSC1.OSC1WT[1:0] bits
is 3.6 V or higher.
DD
Seiko Epson Corporation
(Stop using peripheral circuits)
(Remove system protection)
(OSC1, IOSC 1.8 MHz or 0.9 MHz).
(Switch to mode1)
(Discharge)
(Set to normal mode)
(Stop discharging)
(Set to automatic mode)
(Set system protection)
(Stop using peripheral circuits)
(Remove system protection)
(Switch to mode0)
(Set to normal mode)
(Set to automatic mode)
(Set system protection)
2-3
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