External Memory Interface Handbook Volume 2: Design Guidelines

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ID 683385
Date 5/08/2017
Public
Document Table of Contents

7.3.3.2.1. Memory Initialization Options for DDR2

Memory Initialization Options—DDR2

Address and command parity

Enables address/command parity checking. This is required for Registered DIMM.

Mode Register 0

Burst length

Specifies the burst length.

Read burst type

Specifies accesses within a given burst in sequential or interleaved order.

Specify sequential ordering for use with the Intel memory controller. Specify interleaved ordering only for use with an interleaved-capable custom controller, when the Generate PHY only parameter is enabled on the PHY Settings tab.

DLL precharge power down

Determines whether the DLL in the memory device is in slow exit mode or in fast exit mode during precharge power down. For more information, refer to memory vendor data sheet.

Memory CAS latency setting

Determines the number of clock cycles between the READ command and the availability of the first bit of output data at the memory device. For more information, refer to memory vendor data sheet speed bin table.

Set this parameter according to the target memory speed grade and memory clock frequency.

Mode Register 1

Output drive strength setting

Determines the output driver impedance setting at the memory device.

To obtain the optimum signal integrity performance, select the optimum setting based on the board simulation results.

Memory additive CAS latency setting

Determines the posted CAS additive latency of the memory device.

Enable this feature to improve command and bus efficiency, and increase system bandwidth. For more information, refer to the Optimizing the Controller chapter.

Memory on-die termination (ODT) setting

Determines the on-die termination resistance at the memory device.

To obtain the optimum signal integrity performance, select the optimum setting based on the board simulation results.

Mode Register 2

SRT Enable

Determines the selfrefresh temperature (SRT). Select 1x refresh rate for normal temperature (0-85C)or select 2x refresh rate for high‑temperature (>85C).

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