6402 datasheet(33/250 Pages) INTEL

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Intel® 6400/6402 Advanced Memory Buffer Datasheet

DDR Interface

DCALCSR until the start bit is cleared. After the start bit is cleared, firmware waits a

period of time based on DRAM command timing specifications before issuing a new

command through the DCALCSR.

3.8.1.1

OCD EMRS Commands

FB DIMM DRAM timing is set up to work with OCD default calibration. Using the

DCALCSR and DCALADDR registers, EMRS OCD default and OCD exit commands can be

sent to the DRAMs.

Sending OCD EMRS drive(0), drive(1), or adjust DRAM commands may have

implementation dependent outcomes and should not be used in normal operation.

3.8.1.2

MRS Command Example

The following example shows how to send out an MRS command:

1. Write a value of 0x02320000 to the DCALADDR csr. This will configure the address/

bank bus for an MRS command with burst length 4, CAS latency 3, and write

recovery 2.

2. Write a value of 0x80000003 to the DCALCSR. This selects the (E)MRS command

mode and initiates the FSM that will issue the command.

3. Poll the DCALCSR until bit 31 is cleared to zero by hardware. This indicates that the

FSM has completed the selected operation.

3.8.2

DQS Failure CSR

The DQSFAIL CSR allows the AMB to calibrate properly even when one or more DQS

signals are missing, either through PCB or component failure. DQSFAIL is a 36 bit

DQS signal to be excluded from the automatic DDR bus calibration. Hardware will also

detect missing DQS signals and automatically exclude them from calibration.

6402 Datasheet(PDF) 33 Page - Intel Corporation