# Pastebin tWjLMbE4
ERROR:Pack:2908 - The I/O component "crg_ddram_clock_n" has an illegal
   IOSTANDARD value.  The IOB component is configured to use single-ended
   signaling and can not use differential IOSTANDARD value DIFF_SSTL18_II.  Two
   ways to rectify this issue are: 1) Change the IOSTANDARD value to a
   single-ended standard. 2) Correct the I/O connectivity by instantiating a
   differential I/O buffer.
ERROR:Pack:2908 - The I/O component "crg_ddram_clock_p" has an illegal
   IOSTANDARD value.  The IOB component is configured to use single-ended
   signaling and can not use differential IOSTANDARD value DIFF_SSTL18_II.  Two
   ways to rectify this issue are: 1) Change the IOSTANDARD value to a
   single-ended standard. 2) Correct the I/O connectivity by instantiating a
   differential I/O buffer.