Altera ALTDLL Uživatelský manuál stáhnout pdf (Strana 6)

1–2 Chapter 1: About these Megafunctions

Features

ALTDLL and ALTDQ_DQS Megafunctions User Guide © February 2012 Altera Corporation

Features

The ALTDLL and ALTDQ_DQS megafunctions offer the following features:

■ ALTDLL

■ A delay-locked loop (DLL) block to center-align the read strobe with read data.

■ Phase offset control blocks to fine-tune the delay time on the read strobe using

static or dynamic offset.

■ ALTDQ_DQS

■ Supports RLDRAM II memory interface.

■ DDR registers on the input and output paths to read or write to an external

DDR interface.

■ Half-rate registers to enable successful data transfers between the I/O registers

and the core logic.

■ Access to dynamic on-chip termination (OCT) controls to switch between

parallel termination during reads to series termination during writes.

■ Access to I/O delay chains to fine-tune delays on the data or strobe signals

statically or dynamically.

Figure 1–1 shows a high-level overview of how you can connect the ALTDQ_DQS

megafunction with other megafunctions such as ALTPLL, ALTDLL, and ALTIOBUF,

to create a full custom external memory interface. Figure 1–1 shows a 36-bit interface

created with ALTDQ_DQS instantiations, where each instantiation is configured in

the ×9 mode.

Figure 1–1. System-Level View

ALTIOBUF (DQS/DQSN)

ALTIOBUF (BIDIR_DQ)

ALTIOBUF (INPUT_DQ)

ALTIOBUF (OUTPUT_DQ)

ALTDQ_DQS

ALTDLL

ALTPLL

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Altera ALTDLL Uživatelský manuál Strana 6