ID:186193 GXB receiver channel "<name>" has the SLPBK port connected and the associated GXB transmitter channel "<name>" has the SRLPBK port connected. The SLPBK port and the SRLPBK port must not be driven high at the same time

CAUSE: Serial loopback and reverse-serial loopback cannot be enabled at the same time. Therefore, the SLPBK and SRLPBK ports must not be driven high at the same time. Only one of these ports (or none) can be driven high at a given point in time. Additionally, when serial loopback is enabled on the specified gigabit transceiver block (GXB) receiver channel (SLPBK is driven high), the VODCTRL port should enable a 800mV or greater Voltage Output Differential (VOD) control setting (assuming 100 Ohms termination). When reverse-serial loopback is enabled in the specified GXB transmitter channel (SRLPBK is driven high), the VODCTRL port should enable a 400mV VOD setting (assuming 100 Ohms termination).

ACTION: Use the described settings for successful toggling between serial and reverse-serial loopback functionality. If you use the MegaWizard Plug-In Manager to instantiate the ALTGXB megafunction, the port names are rx_slpbk, tx_srlpbk, and tx_vodctrl; however, because the ALTGXB MegaWizard Plug-In Manager is being deprecated, Altera recommends using ALTGX MegaWizard Plug-In Manager instead.