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CLOCK & POWER MANAGEMENT S3C2410A
7-14
Power_OFF Mode
The block disconnects the internal power. So, there occurs no power consumption due to CPU and the internal logic
except the wake-up logic in this mode. Activating the Power_OFF mode requires two independent power sources.
One of the two power sources supplies the power for the wake-up logic. The other one supplies other internal logics
including CPU, and should be controlled for power on/off. In the Power_OFF mode, the second power supply source
for the CPU and internal logics will be turned off. The wakeup from Power_OFF mode can be issued by the
EINT[15:0] or by RTC alarm interrupt.
Procedure to Enter Power_OFF mode
1. Set the GPIO configuration adequate for Power_OFF mode.
2. Mask all interrupts in the INTMSK register.
Configure the wake-up sources properly including RTC alarm.
The bit of EINTMASK corresponding to the wake-up source has not to be masked in order to let the
corresponding bit of SRCPND or EINTPEND set. Although a wake-up source is issued and the corresponding
bit of EINTMASK is masked, the wake-up will occur and the corresponding bit of SRCPND or EINTPEND will
not be set.
4. Set USB pads as suspend mode. (MISCCR[13:12]=11b)
5. Save some meaning values into GSTATUS3,4 register. These register are preserved during Power_OFF mode.
6. Configure MISCCR[1:0] for the pull-up resisters on the data bus,D[31:0]. If there is an external BUS holder, such
as 74LVCH162245, turn off the pull-up resistors. If not, turn on the pull-up resistors
7. Stop LCD by clearing LCDCON1.ENVID bit.
8. Read rREFRESH and rCLKCON registers in order to fill the TLB.
9. Let SDRAM enter the self-refresh mode by setting the REFRESH[22]=1b.
10. Wait until SDRAM self-refresh is effective.
11. Set MISCCR[19:17]=111b to make SDRAM signals (SCLK0,SCLK1 and SCKE) protected during Power_OFF
mode
12. Set the Power_OFF mode bit in the CLKCON register.