s3c2410a Samsung Semiconductor, Inc., s3c2410a Datasheet - Page 232

• Manufacturer Part Number: s3c2410a
• Description: 16/32-bit Risc Arm Microprocessor
• Manufacturer: Samsung Semiconductor, Inc.

CLOCK & POWER MANAGEMENT
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.
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
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
12. Set the Power_OFF mode bit in the CLKCON register.
7-14
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.
as 74LVCH162245, turn off the pull-up resistors. If not, turn on the pull-up resistors
mode
S3C2410A