1-12
Chapter 1: Product introduction
To erase the RTC RAM:
1. Turn OFF the computer and unplug the power cord.
2. Move the jumper cap from pins 1-2 (default) to pins 2-3. Keep the cap on pins 2-3
for about 5-10 seconds, then move the cap back to pins 1-2.
3. Plug the power cord and turn ON the computer.
4. Hold down the <
Del> key during the boot process and enter BIOS setup to re-
enter data.
Except when clearing the RTC RAM, never remove the cap on CLRTC jumper default
position. Removing the cap will cause system boot failure!
• If the steps above do not help, remove the onboard battery and move the jumper
again to clear the CMOS RTC RAM data. After clearing the CMOS, reinstall the
battery.
• You do not need to clear the RTC when the system hangs due to overclocking. For
system failure due to overclocking, use the CPU Parameter Recall (C.P.R.) feature.
Shut down and reboot the system, then the BIOS automatically resets parameter
settings to default values.
2. USB device wake-up (3-pin USBPWF)
Set these jumpers to +5V to wake up the computer from S1 sleep mode (CPU stopped,
DRAM refreshed, system running in low power mode) using the connected USB
devices. Set to +5VSB to wake up from S3 and S4 sleep modes (no power to CPU,
DRAM in slow refresh, power supply in reduced power mode).
• The USB device wake-up feature requires a power supply that can provide 500mA on
the +5VSB lead for each USB port; otherwise, the system would not power up.
• The total current consumed must NOT exceed the power supply capability (+5VSB)
whether under normal condition or in sleep mode.
A55BM-A/USB3
A55BM-A/USB3 USB device wake up
21
2 3
+5V
(Default)
+5VSB
USBPWF