Product Description
23
1.7
Real-Time Clock Subsystem
A coin-cell lithium 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 5 V 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 shows the location of the battery.
