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aTCA-80302PA/PD
3.3 Shelf FRU SEEPROM
2 Shelf FRU SEEPROMS are located on the Backplane. The hardware address for
these SEEPROMs is 0xA4.
The SEEPROMs are the repository of the shelf specific information capabilities of
the system and other user configurable options. The SEEPROMs contain the list of
which slots are connected together, how the update channels are routed, how many
slots are in the system, what the maximum power is to each slot, serial number of
the shelf, backplane topology, etc. The Shelf Manager uses this information to
provide functions such as electronic keying, controlling the power state of the
system, etc.
The Shelf allows for 2 methods to access the chassis FRU data:
• An I2C connection from each Shelf Manager directly to the SEEPROMs on the
backplane.
• SEEPROMs on the backplane exposed as a FRU of the Fan Tray.
3.4 Logic Ground
Figure 3: Logic Ground
The ATCA backplane provides a mechanism to connect Logic Ground and Shelf
Ground. The backplane fixing screw (arrow) is isolated by a plastic washer. To
connect Logic Ground and Shelf Ground remove the screw, remove the plastic
washer and re-install the screw.
The default factory assembly isolates Logic Ground from Shelf Ground.
