Altera ALTDLL - Manual (Page 13)

2–7 Chapter 2: Getting Started
Design Example: Implementing Read Paths Using Stratix III Devices
ALTDLL and ALTDQ_DQS Megafunctions User Guide © February 2012 Altera Corporation
8. On the DLL Offset Controls/Optional Ports page, specify the parameters as
shown in Table 2–4 .
9. Click Finish.
10. Click Finish. The ALTDLL instance is generated.
11. Click OK to close the Symbol window.
12. Place the instance on the Block Editor.
Generate the ALTDQ_DQS Megafunction
To generate the ALTDQ_DQS megafunction, perform the following steps:
1. Double-click anywhere on the Block Editor window. The Symbol window appears.
2. Click MegaWizard Plug-In Manager. Page 1 of the MegaWizard Plug-In Manager
appears.
3. Select Create a new custom megafunction variation.
4. 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_input_path.v.
5. On the Parameter Settings page, specify the parameters as shown in Table 2–5 .
These parameters configure the general settings for the ALTDQ_DQS instance.
DQS Delay Buffer Mode Low
Refer to Stratix III Device Datasheet: DC and
Switching Characteristics of Stratix III Devices
chapter in the Stratix III Device Handbook, and
pick a DLL mode that supports 150 MHz and
find the DLL setting.
Input Clock Frequency 150 MHz
Turn on jitter reduction Turned off.
Table 2–4. ALTDLL Parameter Settings/DLL Offset Controls/Optional Ports Settings
Settings Value
DLL Phase Offset Control A
Instantiate dll_offset_ctrl block
Turned off.
The design is intended to run slow, so you do
not need to select this parameter. However, if
the read timing is unbalanced, you can
fine-tune the DQS phase shift using this
parameter.
DLL Phase Offset Control B
Instantiate dll_offset_ctrl block
Turned off.
Optional Ports
Create a dll_aload port
Turned off.
Optional Ports
Create a dll_dqsupdate port
Turned off.
Table 2–3. ALTDLL GeneraL Settings
Settings Value