Description
When you instantiate the Stratix® IV GX transceiver in PCI Express (PIPE) x4 and x8 configurations for Gen2 data rate, the ALTGX MegaWizard® Plug-in Manager provides the rateswitch input port that is four bits and eight bits wide, respectively.
Altera has identified that asserting the rateswitch[0] port performs the rateswitch function when you simulate the above configurations. The remaining bits of the rateswitch port (rateswitch[7:1] for PCI Express (PIPE) x8 configuration and rateswitch[3:1] for PCI Express (PIPE) x4 configuration) are not functional.
Workaround: Altera recommends that you connect all the bits except rateswitch[0] to zero.