module top ( input clk, output [3:0] led ); (* keep *) wire led_unused; wire gclk; clk_wiz_v3_6 pll(.CLK_IN1(clk), .CLK_OUT1(gclk)); //assign gclk = clk; attosoc soc(.clk(gclk), .led({led_unused, led})); endmodule