Tcl error: ERROR: Argument <clk_object> is a collection with more than one object. Specify a collection with one object. while executing "get_clock_info -period [get_clocks [lindex $fclk_setting_name 0]] - Tcl error: ERROR: Argument <clk_object> is a collection with more than one object. Specify a collection with one object. while executing "get_clock_info -period [get_clocks [lindex $fclk_setting_name 0]] Description For Intel® Arria® 10 and Intel® Cyclone® 10 GX devices, when using LVDS SERDES Intel FPGA IP with External PLL configuration in Intel® Quartus® Prime Pro Edition software, you may find the below error during timing analysis while executing “Report RSKM.” Tcl error: ERROR: Argument is a collection with more than one object. Specify a collection with one object. while executing "get_clock_info -period get_clocks [index $fclk_setting_name 0]] Resolution To avoid this error, add the below command in the sdc file. derive_pll_clocks -create_base_clocks This information has been added to the LVDS SERDES Intel® FPGA IP User Guide: Intel® Arria® 10 and Intel® Cyclone® 10 GX Devices chapter Timing Analysis when Using PLL Core Clocks Custom Fields values: ['novalue'] Troubleshooting 1507828377 , 14010754927 False ['novalue'] ['FPGA Dev Tools Quartus® Prime Software Pro'] No plan to fix 19.3 ['Arria® 10 FPGAs and SoCs', 'Cyclone® 10 GX FPGA'] ['novalue'] ['novalue'] ['novalue']