User guide

Chapter 5: Functional Description—ALTMEMPHY 5–7

Block Description

December 2010 Altera Corporation External Memory Interface Handbook Volume 3

Section II. DDR3 SDRAM Controller with ALTMEMPHY IP User Guide

1 The mimic path in Arria II GX, Stratix III and Stratix IV devices is similar to

Figure 5–3. The only difference is that the

mem_clk[0]

pin is generated by DDIO

mem_clk_n[0]

is generated by signal splitter.

DDR3 SDRAM With Leveling

The calibration process for the DDR3 SDRAM PHY (with leveling) assumes an

interface in an unbuffered DIMM format, where the clock uses a fly-by termination,

refer to Figure 5–4.

With fly-by termination, each DDR3 SDRAM device on the DIMM sees the CK/CKn

edges at different times. Therefore, the sequencer must adjust the clock to launch the

DQS/DQSn and DQ signals so that it is appropriately aligned to the CK/CKn signals

on each device.

The DDR3 SDRAM leveling sequencer during calibration writes to the following

locations:

Figure 5–3. Mimic Path

mem_clk[0]

datain

ddiodatain

outclk

ALTPLL

mem_clk_2x

measure_clk

mimic_data_in

measure_clk

alt_mem_phy_mimic

combout

Figure 5–4. DDR3 SDRAM Unbuffered Module Clock Topology

DQS/DQ

DQS/DQDQS/DQ

DQS/DQ

CK/CK#

DQS/DQ DQS/DQ