information. Event generation over IPMB-L bus to reach the AMC Carrier that forward it to the ShMc
ensure that ‘post-mortem’ logging information is available even if the power of the AMC is disabled.
The onboard DC voltages, currents, and temperature are monitored by the MMC microcontroller
device. The MMC will send an event to the Carrier AMC if any of the thresholds are exceeded.
To increase the reliability of the SBC management subsystem, an external watchdog
supervisor only for the MMC is implemented. The MMC must strobes the external watchdog at two-
second intervals to ensure continuity of operation of the board’s management subsystem. If the
MMC ceases to strobe the watchdog supervisor, the watchdog isolates the MMC from the IPMBs and
resets the MMC. The watchdog supervisor does not reset the payload power and the restart of the
MMC will not affect the payload and will restore the previous Module Hot Swap state. The watchdog
timeout expires after six seconds if strobes are not generated. 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 MMC is implemented in a second microcontroller. This microcontroller
is responsible to monitor the MMC and to manage MMC fail safe firmware upgrade process. The
name of this second microcontroller is the Firmware Upgrade Manager (FWUM). The FWUM can
handle two Firmware code that are stored in two external SEPROM memories. If a failure occurs
during firmware upgrade, the FWUM will automatically rollback to the redundant MMC firmware
image.
2.3.1
Sensor Data Record (SDR)
Every sensor on the baseboard is associated with a Sensor Data Record (SDR). Sensor Data Records
contain information about the sensors identification such as sensor type, sensor name, sensor unit.
SDR also contain the configuration of a specific sensor such as threshold/hystheresis, event
generation capabilities that specifies sensor behaviour. Some field of the sensor SDR are
configurable through IPMI v1.5 command and are set to built-in initial value. Finally one field wich
is the sensor owner must reflect the module addresses that allow the AMC Carrier to identify the
owner of the SDR when it is scaned from the module management controller and merged within the
AMC Carrier Device SDR repository.
From IPMI prespective, the
SBC
management controller is set up as a satellite management
controller (SMC). It does support sensor devices, and use the IPMI static sensor population feature
of IPMI v1.5 to merge the hot swaped AMC sensor with the
SBC
sensors population. The usual
way the AMC Carrier is informed about an AMC insertion is through the AMC Module Hot Swap sensor
and a radial presence line on the AMC connector. All SDRs can be queried using Device SDR
commands to the firmware. Module sensors that have been implemented are listed below.
2-6
AM4520 User’s Guide
