module explicit();
reg clk,d,rst,pre;
wire q;
// Here q_bar is not connected
// We can connect ports in any order
dff u0 (
.q (q),
.d (d),
.clk (clk),
.q_bar (),
.rst (rst),
.pre (pre)
);
endmodule
// D fli-flop
module dff (q, q_bar, clk, d, rst, pre);
input clk, d, rst, pre;
output q, q_bar;
reg q;
assign q_bar = ~q;
always @ (posedge clk)
if (rst == 1'b1) begin
q <= 0;
end else if (pre == 1'b1) begin
q <= 1;
end else begin
q <= d;
end
endmodule
