Real-Time Clock, Cmos Sram, And Battery; Intel 82802Ab 4 Mbit Fwh - Intel D850MVSE Specification

Intel Desktop Board D850MD/D850MV Technical Product Specification
1.8.3.2 SCSI Hard Drive Activity LED Connector
The SCSI hard drive activity LED connector is a 1 x 2–pin connector that allows an add-in
SCSI controller to use the same LED as the onboard IDE controller. For proper operation, this
connector should be wired to the LED output of the add-in SCSI controller. The LED indicates
when data is being read from, or written to, both the add-in SCSI controller and the IDE controller.
For information about
The location of the SCSI hard drive activity LED connector
The signal names of the SCSI hard drive activity LED connector

1.8.4 Real-Time Clock, CMOS SRAM, and Battery

The real-time clock provides a time-of-day clock and a multicentury 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, if previously saved, will be loaded into CMOS
RAM at power-on.
For information about
Proper date access in systems with D850MD and D850MV boards

1.8.5 Intel 82802AB 4 Mbit FWH

The FWH provides the following:
System BIOS program
System security and manageability logic that enable protection for storing and updating of
platform information
30
Refer to
Figure 17, page 70
Table 42, page 69
Refer to
Section 1.3, page 18