Why do the clock frequencies in the ALTLVDS_TX megafunction different than those I enter in MegaWizard Plug-In Manager?

Description

Due to a problem in the Quartus® II software versions 10.0 and later, megafunctions generated with the ALTLVDS_TX MegaWizard™ Plug-In Manager may include clock frequencies that do not match what you enter for the What is the output data rate? parameter. This problem only affect Windows 64-bit operating systems.

To confirm that the Nominal VCO frequency for the ALTLVDS_TX PLL matches your data rate, follow these steps:

1. In the Compilation Report, expand Fitter
2. Expand Resource Section
3. Check the PLL Summary

To work around this problem, perform the following steps:

1. Close the Quartus II software.
2. Append %QUARTUS_ROOTDIR%\bin64 to the User environment variable PATH.
3. Restart the Quartus II software to use ALTLVDS_TX MegaWizard Plug-In Manager.

This problem is fixed beginning with the Quartus II software version 11.0.

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