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Keyboard and Mouse
The keyboard/mouse controller is PS/2-compatible. The system may be
locked automatically if there is no keyboard or mouse activity for a
predefined length of time, if specified through the SCU. Once the inactivity
(lockout) timer has expired, the keyboard or mouse does not respond until
the previously stored password is entered.
Server Management
Server Management features are implemented using three microcontrollers
and one PLD:
•
Motherboard Management Controller (BMC)
•
Front Panel Controller (FPC)
•
Processor Board Controller (PBC)
•
Distributed Integrated Server Management Interface Controller
(DISMIC)
BMC—The BMC is an 8051-compatible microcontroller located on the
motherboard. The BMC monitors motherboard power supply and SCSI
termination voltages using an external Analog to Digital Converter (ADC);
the BMC checks the status of the fan failure indicators. The BMC also
monitors system temperature sensors on the intelligent management bus.
When any monitored parameter is outside defined thresholds, the BMC
generates a system management interrupt (SMI). The BMC also provides
general-purpose I/O (GPIO) functions and acts as the primary
communications gateway to the FPC, PBC, and DISMIC by providing
support routines for IMB and ISA communications
An EEPROM associated with the secondary motherboard temperature
sensor contains the values for the chassis ID, motherboard ID, power state,
and motherboard temperature during power-off conditions. The BMC
manages these values via IMB.
FPC—The FPC, located on the motherboard, manages system power on/off
control, system reset, and front panel NMI buttons, along with an external
IMB interface. The +5V standby power supply powers the device so that it
retains power even when system power is off. The FPC controls main
power to the motherboard and is responsible for monitoring all sources of
power control both on and off the motherboard, including the Front Panel,
Server Monitor Mechanism, PIIX4, and RTC power control signals. The
FPC also detects chassis intrusion by monitoring an external switch and
remembers the last power state if AC power is unterrupted.
20
Chapter 1 - Motherboard Description
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