10
Floppy Controller
In the Setup program, the floppy interface can be configured for the following floppy
drive capacities and sizes:
•
=
360 KB, 5.25-inch
•
=
1.2 MB, 5.25-inch
•
=
720 KB, 3.5-inch
•
=
1.2 MB, 3.5-inch (driver required)
•
=
1.25/1.44 MB, 3.5-inch
Keyboard and Mouse Interface
PS/2 keyboard and mouse connectors are located on the back panel. The 5 V lines
to these connectors are protected with a PolySwitch circuit that, like a self-healing
fuse, re-establishes the connection after an over-current condition is removed.
The keyboard controller contains the AMI Megakey keyboard and mouse controller
code, which provides the keyboard and mouse control functions, and supports
password protection for power on/reset. A power on/reset password can be
specified in Setup.
The keyboard controller also supports the hot-key sequence <Ctrl><Alt><Del> for a
software reset. This key sequence resets the computer’s software by jumping to the
beginning of the BIOS code and running the Power-On Self Test (POST).
Real-time Clock, CMOS SRAM, and Battery
The clock provides a time-of-day clock and a multicentury calendar with alarm
features and century rollover.
The time, date, and CMOS values can be specified in the Setup program. The
CMOS values can be returned to their defaults by using the Setup program.
An external coin-cell battery 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 3.3-V 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 V applied.
IDE Support
The motherboard has two independent bus-mastering PCI IDE interfaces. These
interfaces support PIO Mode 3, PIO Mode 4, ATAPI devices (e.g., CD-ROM), and
DMA mode transfers. The BIOS supports logical block addressing (LBA) and
cylinder head sector (CHS) translation modes. The BIOS automatically detects the
IDE device transfer rate and translation mode.
