Altera ALTDLL Manual de usuario descargar pdf (Pagina 87)

4–51 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

Instantiate the ALTDQ_DQS Megafunction

To instantiate the ALTDQ_DQS megafunction, perform the following steps:

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

MegaWizard Plug-In Manager appears.

2. Select Create a new custom megafunction variation.

3. Click Next. Page 2a of the MegaWizard Plug-In Manager appears. Select

ALTDQ_DQS, and Verilog HDL, and type the file name as dq_dqs_inst.v.

4. On the Parameter Settings page of the ALTDQ_DQS parameter editor, specify the

parameters as shown in Table 4–26.

5. In the Advanced Options tab of the ALTDQ_DQS parameter editor, on the DQS

IN page, specify the parameters as shown in Table 4–27. These parameters

configure the DQS input path of the ALTDQ_DQS instance.

Table 4–26. Parameter Settings

Parameter Value

RLDRAM II Mode NONE

Data mask pin group NONE

Q valid signal group NONE

Number of bidirectional DQ 8

Number of input DQ 0

Number of output DQ 1

Number of stages in dqs_delay_chain 2

DQS Input Frequency 333 MHz

Use half-rate components Turned on

Use Dynamic OCT Turned off

Add memory interface specific fitter grouping assignments Turned off

Table 4–27. Advanced Options (DQS IN) (Part 1 of 2)

Parameter Sub-options Value

Enable DQS Input Path — Turned on

Enable Dynamic Delay Chain — Not selected

Enable dqs_delay_chain —Selected

Advanced delay chain options Select dynamically using

configuration registers

Turned off

DQS delay chain ‘delayctrlin’ port

source

DLL

DQS Delay Buffer Mode HIGH

DQS Phase Shift 9000..

Enable DQS offset Control Turned off

Enable DQS delay chain latches Turned off

Enable DQS busout delay chain — Turned on

Enable DQS enable block — Turned on

Enable DQS enable control block — Turned on

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