Description
You may encounter this error message in the Quartus® Prime software, if you are using Cyclone® IV devices and your output pin uses the LVDS_E_3R I/O standard and is located on a CLKOUT pin.
Resolution
There is no plan to modify the Quartus Prime software to fix this issue.
You should not assign an output pin with the LVDS_E_3R I/O standard to a CLKOUT pin when using Cyclone IV devices.
