Intel Desktop Board DH55PJ Product Guide
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PCI Express WAKE# Signal Wake-up Support
When the WAKE# signal on a PCI Express bus add-in card is asserted, the computer
wakes from an ACPI S1, S3, S4, or S5 state.
Wake from PS/2 Devices
PS/2 device activity can wake the computer from an ACPI S1, S3, S4, or S5 state.
When the computer is in the S4 state, any key can be used to wake the computer
provided a supported operating system is installed. When the computer is in the S5
state, the only PS/2 activity that will wake the computer is either the Alt-Print Screen
key combination or the “Power” key that is available on some keyboards. The BIOS
can be used to select between either of the key combinations.
Wake from Serial Port
Serial port activity wakes the computer from an ACPI S1 or S3 state.
Speaker
A piezoelectric speaker is mounted on the Desktop Board. The speaker provides
audible error code (beep code) information during the Power-On Self-Test (POST).
Refer to Appendix A for a description of the board’s beep codes.
Real-Time Clock Subsystem
A coin-cell battery (CR2032) powers the real-time clock and CMOS memory. When
the computer is not plugged into a wall socket, the battery has an estimated life of
three years. When the computer is plugged in, the standby current from the power
supply extends the life of the battery.
The clock is accurate to
±
13 minutes/year at 25 ºC with standby power applied by the
power supply.
NOTE
If the battery and AC power fail, date and time values will be reset and the user will be
notified during the POST.
When the battery voltage drops below a certain level, the BIOS Setup program
settings stored in CMOS RAM (for example, the date and time) might not be accurate.
Replace the battery with an equivalent one. Go to page 52 for instructions on how to
replace the battery.
