When you implement the DDR3 SDRAM Controller with UniPHY in a MAX® 10 device and add pin location assignments to the DQSn pins in the QSF file, you may get following fitter error.
Error (165011): altmemphy pin placement was unsuccessful
Error (13130): The assigned location PIN <pin_number> for DQSn pin mem_dqs_n[*] is not a legal location
As DQSn is a pseudo differential pin of DQS, a pin location assignment for DQSn is not needed. The pin location assignment on the DQS pin is sufficient.
To work around this error, remove the pin location assignment for the DQSn pins in the Assignment Editor or the QSF file.