NEC Intel Xeon E5-2420 N8101-571F User Manual

Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 Product Families

143

Datasheet Volume One

This chapter describes the processor signals. They are arranged in functional groups 

according to their associated interface or category.

DDR{0/1/2/3}_BA[2:0]

Bank Address. Defines the bank which is the destination for the 

current Activate, Read, Write, or Precharge command.

DDR{0/1/2/3}_CAS_N

Column Address Strobe.

DDR{0/1/2/3}_CKE[5:0]

Clock Enable.

DDR{0/1/2/3}_CLK_DN[3:0]
DDR{0/1/2/3}_CLK_DP[3:0]

Differential clocks to the DIMM. All command and control signals 

are valid on the rising edge of clock.

DDR{0/1/2/3}_CS_N[9:0]

Chip Select. Each signal selects one rank as the target of the 

command and address.

DDR{0/1/2/3}_DQ[63:00]

Data Bus. DDR3 Data bits.

DDR{0/1/2/3}_DQS_DP[17:00]
DDR{0/1/2/3}_DQS_DN[17:00]

Data strobes. Differential pair, Data/ECC Strobe. Differential 

strobes latch data/ECC for each DRAM. Different numbers of 

strobes are used depending on whether the connected DRAMs are 

x4,x8. Driven with edges in center of data, receive edges are 

aligned with data edges.

DDR{0/1/2/3}_ECC[7:0]

Check bits. An error correction code is driven along with data on 

these lines for DIMMs that support that capability

DDR{0/1/2/3}_MA[15:00]

Memory Address. Selects the Row address for Reads and writes, 

and the column address for activates. Also used to set values for 

DRAM configuration registers. 

DDR{0/1/2/3}_MA_PAR

Odd parity across Address and Command.

DDR{0/1/2/3}_ODT[5:0]

On Die Termination. Enables DRAM on die termination during Data 

Write or Data Read transactions.

DDR{0/1/2/3}_PAR_ERR_N

Parity Error detected by Registered DIMM (one for each channel).

DDR{0/1/2/3}_RAS_N

Row Address Strobe.

DDR{0/1/2/3}_WE_N

Write Enable.