Description
When you use the DDR3 SDRAM controller with UniPHY and follow the FPGA wiki page (Intel communities) Measuring_Channel_Signal_Integrity to calculate ISI parameters in the Board Settings tab of the DDR3 IP GUI, you may get a negative number. You will get the above error message if the negative number is entered into the GUI.
Resolution
To avoid the error message, enter zero if you calculate a negative number for ISI parameters.