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Preliminary Data Sheet E1339E20 (Ver. 2.0)

5

Interfaces

Figure Block Diagram AMB Interfaces shows the AMB and all of its interfaces. They consist of two FB-DIMM links,

one DDR2 channel and an SMBus interface. Each FB-DIMM link connects the AMB to a host memory controller or

an adjacent FB-DIMM. The DDR2 channel supports direct connection to the DDR2 SDRAMs on an FB-DIMM.

Memory Interface

NB FBD

in Link

SB FBD

out Link

SB FBD

in Link

NB FBD

out Link

SMB

AMB

Block Diagram AMB Interfaces

Interface Topology

The FB-DIMM channel uses a daisy-chain topology to provide expansion from a single DIMM per channel to up to 8

DIMMs per channel. The host sends data on the southbound link to the first DIMM where it is received and redriven

to the second DIMM. On the southbound data path each DIMM receives the data and again re-drives the data to the

next DIMM until the last DIMM receives the data. The last DIMM in the chain initiates the transmission of data in the

direction on the host (a.k.a. northbound). On the northbound data path each DIMM receives the data and re-drives

the data to the next DIMM until the host is reached.

AMB

Host

Southbound

n/c

n/c

Nourthbound

AMB

AMB

AMB

Block Diagram FB-DIMM Channel Southbound and Northbound Paths