Try   HackMD

/* D 触发器(D Flip-Flop) Verilog */

module DFF (
input wire clk,
input wire rst_n, // 低电平复位
input wire d,
output reg q
);
always @(posedge clk or negedge rst_n) begin
if (!rst_n)
q <= 0;
else
q <= d;
end
endmodule