Subversion Repositories ddr3_synthesizable_bfm

/*

Multibits Shift Register

2010-2011 sclai <laikos@yahoo.com>

This library is free software; you can redistribute it and/or modify it

 under the terms of the GNU Lesser General Public License as published by

 the Free Software Foundation; either version 2.1 of the License,

 or (at your option) any later version.

 This library is distributed in the hope that it will be useful, but

 WITHOUT ANY WARRANTY; without even the implied warranty of

 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public

 License along with this library; if not, write to the Free Software

 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307

 USA

*/

module ddr3_sr4 #(

parameter PIPE_LEN=7

)(

input wire        clk,

input wire [3:0] shift_in,

output wire[3:0] shift_out

);

//register to hold value

reg [PIPE_LEN-1:0] d0;

reg [PIPE_LEN-1:0] d1;

reg [PIPE_LEN-1:0] d2;

reg [PIPE_LEN-1:0] d3;

always @(posedge clk)

begin

  d3  <={shift_in[ 3],d3[PIPE_LEN-1:1]};

  d2  <={shift_in[ 2],d2[PIPE_LEN-1:1]};

  d1  <={shift_in[ 1],d1[PIPE_LEN-1:1]};

  d0  <={shift_in[ 0],d0[PIPE_LEN-1:1]};

end

assign shift_out={d3[0],d2[0],d1[0],d0[0]};

endmodule