Altera ALTDLL Manual de usuario descargar pdf (Pagina 85)

4–49 Chapter 4: Functional Description

Design Example: Implementing Half-Rate DDR2 Interface in Stratix III

ALTDLL and ALTDQ_DQS Megafunctions User Guide © February 2012 Altera Corporation

Design Example: Implementing Half-Rate DDR2 Interface in Stratix III

Devices

This section describes a design example that uses the DLL and DQ/DQS circuitry

with half-rate DDR2 external memory interface in Stratix III devices. The memory

interface is running at 333.333 MHz with 8-bit bidirectional DQ pins, a 1-bit output

DQ pin, and a 1-bit differential DQS pin.

f The design examples are available next to the ALTDLL and ALTDQ_DQS

Megafunction User Guides on the Documentation: User Guides page of the Altera

website.

Procedure

This example describes the following steps:

■ Instantiate the ALTDLL Megafunction

■ Instantiate the ALTDQ_DQS Megafunction

■ Instantiate the ALTIOBUF Megafunction

■ Simulate the Design

Instantiate the ALTDLL Megafunction

To instantiate the ALTDLL megafunction, perform the following steps:

1. Open the altdll_altdq_dqs_DesignExample_ex2.zip project and extract the

altdll_altdq_dqs_design_ex2.qar file.

2. In the Quartus II software, open the altdll_altdq_dqs_design_ex2.qar file and

restore the archived file into your working directory.

3. On the Tools menu, click MegaWizard Plug-In Manager. Page 1 of the

MegaWizard Plug-In Manager appears.

4. Select Create a new custom megafunction variation.

5. Click Next. Page 2a of the MegaWizard Plug-In Manager appears. Select ALTDLL,

and Verilog HDL , and type the file name as dll_inst.v.

6. On the Parameter Settings tab, on the General page, specify the parameters as

shown in Table 4–24. These parameters configure the general settings for the

ALTDLL instance.

Table 4–24. General Settings (Part 1 of 2)

Settings Value

Currently selected device family Stratix III

Match project/default Turned on

Number of Delay Chains 10

DQS Delay Buffer Mode High

Input Clock Frequency 333 MHz

Turn on jitter reduction Turned off

1 2 ... 80 81 82 83 84 85 86 87 88 89 90 ... 116 117

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