[HDLBits] Dff16e

Create 16 D flip-flops. It's sometimes useful to only modify parts of a group of flip-flops. The byte-enable inputs control whether each byte of the 16 registers should be written to on that cycle. byteena[1] controls the upper byte d[15:8], while byteena[0] controls the lower byte d[7:0].

resetn is a synchronous, active-low reset.

All DFFs should be triggered by the positive edge of clk.

module top_module (
    input clk,
    input resetn,
    input [1:0] byteena,
    input [15:0] d,
    output [15:0] q
);
    always@(posedge clk) begin
        if(~resetn)
            q<=16'b0;
        else begin
            if(byteena[0])
                q[7:0]<=d[7:0];
            if(byteena[1])
                q[15:8]<=d[15:8];
        end
    end
endmodule