IO port ‘sys_clk’ is driving multiple buffers. This will lead to unplaceable/unroutable situation. The buffers connected are:     video_clock_inst/inst/clkin1_ibufg {IBUF}     adc_pll_inst/inst/clkin1_ibufg {IBUF}-FPGA常见问题社区-FPGA CPLD-ChipDebug