Intel S875WP1-E manual Real-Time Clock, CMOS SRAM, and Battery, Recovering the CMOS

Real-Time Clock, CMOS SRAM, and Battery

The real-time clock provides a time-of-day clock and a multi-century calendar with alarm features. The real-time clock supports 256 bytes of battery-backed CMOS SRAM in two banks that are reserved for BIOS use.

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.

The time, date, and CMOS values can be specified in the BIOS Setup program. The CMOS values can be returned to their defaults by using the BIOS Setup program.

✏NOTE

If the battery and AC power fail, custom defaults, will be loaded into CMOS

RAM at power-on if they defaults have been previously saved.

Recovering the CMOS

In the unlikely event that the CMOS should be corrupt, it can be cleared by using a jumper setting on the server board. To recover the CMOS and return the settings to the default value:

1.Power down the server and unplug all AC power cables.

2.Remove the cover from the chassis.

3.Move the jumper at jumper block J8G1 to cover pins 2 and three. For the location of jumper block J8G1, see the figure below.

J8G1

1 2 3

TP00200

Figure 5. Location of Clear CMOS Jumper

32 Intel Server Board S875WP1-E Product Guide