Intel DQ77MK, User Manual

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Intel Desktop Board DQ77MK Technical Product Specification
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1.6 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 3.3 VSB applied via the power supply 5V STBY rail.
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 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. Figure 1 on page 15 shows the location of the battery.
1.7 Legacy I/O Controller
The I/O controller provides the following features:
•
One serial port
•
Serial IRQ interface compatible with serialized IRQ support for PCI systems
• Intelligent power management, including a programmable wake-up event interface
•
Conventional PCI bus power management support
The BIOS Setup program provides configuration options for the I/O controller.