module top ( input clki, output [3:0] led ); (* keep *) wire led_unused; wire clk; BUFGCTRL clk_gb ( .I0(clki), .CE0(1'b1), .CE1(1'b0), .S0(1'b1), .S1(1'b0), .IGNORE0(1'b0), .IGNORE1(1'b0), .O(clk) ); attosoc soc(.clk(clk), .led({led_unused, led})); endmodule