Digital Equipment AlphaServer 1200, Руководство по обслуживанию

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System Overview 1-35
Monitor
The I
2
C bus monitors the state of system conditions scanned by the PC logic. There
are two registers the PC logic writes data to:
•
One records the state of the fans and power supplies and is latched when there is
a fault.
•
The other causes an interrupt on the I
2
C bus when a CPU or system fan fails, an
over-temperature condition exists, or power supplied to the system exhibits an
over-current condition.
The interrupt received by the I
2
C bus controller on PCI 0 and passed on to the IOD 0
chip set alerts the system of imminent power shutdown. The controller has 30
seconds to read the two registers and store the information in the EEPROM on the
motherboard. The SRM console command show power reads these registers.
Fault Display
The OCP display is written through the I
2
C bus.
Error State
Error state is stored for power, fan, and over-temperature conditions on the I
2
C bus.
Configuration Tracking
Each CPU and each logical section of the system motherboard, (the PCI bridge, the
PCI backplane, the Power Control logic, the Remote Console monitor, and the
system motherboard itself) has an EEPROM that contains information about the
module that can be written and read over the I
2
C bus. All EEPROMs contain the
following information:
•
Module type
•
Module serial number
•
Hardware revision for the logical block
•
Firmware revision