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CP6930-1 User Guide
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ENV: Using default environment
Any changes of the environment can be cleared using the ‘clear_env’ script (provided that ‘clear_env’ itself was not
changed):
=> run clear_env
4.4
IPMI Firmware
The PPC communicates with the Peripheral Manager (PM) using the Keyboard Controller Style (KCS) interface. The boot-
loader is able to communicate with the PM, e.g. for POST error logging purposes and fault resilient purposes.
The memory subsystem of the PM consists of an integrated flash memory to hold the PM operation code and integrated RAM
for data. The field replaceable unit (FRU) inventory information is stored in the nonvolatile memory on an EEPROM con-
nected via a local I2C interface to the PM microcontroller. It is possible to store up to 4 Kbytes within the FRU inventory
information. Communication over IPMB bus to the ShMC ensures that ‘post-mortem’ logging information is available even if
the main processor becomes disabled.
The PM provides several I2C bus connections. Two are used as the redundant IPMB bus connections to the backplane, one
for the Board Sensors and one is for local EEPROM storage.
If an IPMB bus fault or PM failure occurs, IPMB isolators are used to switch and isolate the backplane/system IPMB bus from
the faulted Hub Board. If possible, the PM activates the redundant IPMB bus to re-establish system management communi-
cation to report the fault.
The onboard DC voltage, current, and temperature sensors are monitored by the PM microcontroller continuously. The PM
will log an event into the ShMC’s System Event Log (SEL) if any of the thresholds are exceeded.
To increase the reliability of the Hub board management subsystem, an external watchdog supervisor for the PM is imple-
mented. The PM strobes the external watchdog at two-second intervals to ensure continuity of operation of the board’s
management subsystem. If the PM ceases to strobe the watchdog supervisor for more than six seconds, the watchdog iso-
lates the PM from the IPMBs and resets the PM. The watchdog supervisor does not reset the payload power and the restart of
the PM will not affect the payload. The external watchdog supervisor is not configurable and must not be confused with the
IPMI v1.5 watchdog timer commands.
This external watchdog of the PM is implemented in a second microcontroller. This Firmware Upgrade Manager (FUM) is
responsible for monitoring the PM and for managing the PM fail safe firmware upgrade process. The FUM keeps two PM
Firmware code images in two external SEEPROM memories. If a failure occurs during firmware upgrade, the FUM will auto-
matically rollback to the last known working PM firmware image.
