Technical data

MSC Features and Functions
113
MSC Features and Functions
The MSC has the following basic features and functions:
• Issues a reset signal at power-on.
• A front panel-mounted keyswitch provides a soft power-off to standby condition.
• A front panel-mounted push-button system reset switch.
• A front panel-mounted push-button non-maskable interrupt (NMI) switch.
• Monitors ambient incoming air temperature into the system and adjusts fan speed
accordingly (two speeds). A soft power-off of the system results when ambient
temperature becomes too high for safe operation.
• LED display of ambient over-temperature conditions.
• NVRAM for storing configuration information (1024 x 8 bits).
• Monitors fan rotation and automatically increases to high speed fan operation when
a fan fails. Signals an impending shutdown when a single critical fan fails, or two or
more non-critical fans fail.
• LED display of high fan speed and possible fan tray failure (fan high-speed LED).
• LED display of power supply operation. AC OK LED indicates AC voltage applied
to system. DC OK indicates all power supply DC voltages (+12 V, +5 V, +3.45 V),
and remote DC voltages (3.3 V, 2.4 V, 1.6 V) are present with no error conditions in
the system. The DC OK LED does not indicate regulation or accuracy of the DC
voltages present.
• Provides a 100-Kbps bidirectional communication path between the MSC,
mid-plane, and Hub ASIC IO space on each Node board in the system. This
communication path allows the MSC to receive system status messages from all
Node boards in a system, and to provide status messages from the MSC and all
Node boards in a system. This communication path is referred to as the I2C
interface.