When using GFP v2.1 core, the core might stop functioning in the device after running for about two hours.
It might seem like the core has lost synchronization and remains in HUNT state. At this point, resetting the core will not help.
This problem occurs in the hardware and not in simulation.
This problem occurs because the timeout counter has not been properly disabled. The timeout counter is used for Hardware Evaluation of the GFP core. When GFP core is generated with FULL (Purchased) license, the timeout counter is supposed to be disabled, but it is not and the core stops functioning after about two hours.
If you are using GFP v2.1, be sure to re-generate the core using GFP v2.1 Rev1. This will be available in IP Update #3 scheduled for September 2008. If you need an immediate work-around, open a WebCase with Xilinx Technical Support at: