關於FIFO memory buffer模塊的設計

關於FIFO memory buffer模塊的設計

FIFO memory

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company: 
// Engineer: chensimin
// 
// Create Date: 2018/10/26 13:28:35
// Design Name: 
// Module Name: fifomem
// Project Name: 
// Target Devices: 
// Tool Versions: 
// Description: 
// 
// Dependencies: 
// 
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
// 
//////////////////////////////////////////////////////////////////////////////////



`include      "block_define.v"


module fifomem #(
    parameter  DATASIZE = 8,       //Memory data word width
    parameter  ADDRSIZE = 4 )      //Number of mem address bits       depth = 16
(

    input   [DATASIZE-1 : 0] wdata,
    input   [ADDRSIZE-1 : 0] waddr,
    input                    wclken,
    input                    wfull,
    input                    wclk,

    input   [ADDRSIZE-1 : 0] raddr,
    output  [DATASIZE-1 : 0] rdata
 );


//------------------------------------------------------------------------

`ifdef VENDORRAM

// instantiation of a vendor's dual-port RAM

blk_mem_gen_0 mem (
  .clka(wclk),    // input wire clka
  .ena(wclken),      // input wire ena
  .wea(~wfull),      // input wire [0 : 0] wea
  .addra(waddr),  // input wire [3 : 0] addra
  .dina(wdata),    // input wire [7 : 0] dina
  .clkb(wclk),    // input wire clkb
  .addrb(raddr),  // input wire [3 : 0] addrb
  .doutb(rdata)  // output wire [7 : 0] doutb
);

`else
// RTL Verilog memory model

localparam DEPTH = 1<<ADDRSIZE;
reg [DATASIZE-1 : 0] mem[0 : DEPTH-1];

assign rdata = mem[raddr];

always @(posedge wclk)
    if(wclken && !wfull)
        mem[waddr] <= wdata;

`endif

endmodule

IP 核配置

測試及仿真：

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company: 
// Engineer: chensimin
// 
// Create Date: 2018/10/26 16:34:06
// Design Name: 
// Module Name: testbench
// Project Name: 
// Target Devices: 
// Tool Versions: 
// Description: 
// 
// Dependencies: 
// 
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
// 
//////////////////////////////////////////////////////////////////////////////////


module testbench #(
    parameter  DATASIZE = 8,       //Memory data word width
    parameter  ADDRSIZE = 4  )    //Number of mem address bits       depth = 16


(


    input    wire                       clk,
    input    wire                       rst,

    output   [DATASIZE-1 : 0]           rdata                      

    );


//------------------------------------------------------------

reg [4:0] i = 0;
reg    [DATASIZE-1 : 0]    wdata  = 0;
reg    [ADDRSIZE-1 : 0]    waddr  = 0;
reg                        wclken = 0;
reg    [ADDRSIZE-1 : 0]    raddr = 0;
always @(posedge clk or posedge rst)
begin
    if(rst)
    begin
        i <= 0;
        wdata <= 0;
        waddr <= 0;
        wclken <= 1'b0;
        raddr <= 0;
    end
    else 
    begin
        case(i)
        0:
        begin
            wdata <= 0;
            waddr <= 0;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 0;
        end
        1:
        begin
            wdata <= 1;
            waddr <= 1;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 0;
        end
        2:
        begin
            wdata <= 2;
            waddr <= 2;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 0;
        end
        3:
        begin
            wdata <= 3;
            waddr <= 3;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 0;
        end
        4:
        begin
            wdata <= 4;
            waddr <= 4;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 1; 
        end
        5:
        begin
            wdata <= 5;
            waddr <= 5;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 2;
        end
        6:
        begin
            wdata <= 6;
            waddr <= 6;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 3;
        end
        7:
        begin
            wdata <= 7;
            waddr <= 7;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 4;
        end
        8:
        begin
            wdata <= 8;
            waddr <= 8;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 5;
        end
        9:
        begin
            wdata <= 9;
            waddr <= 9;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 6;
        end
        10:
        begin
            wdata <= 10;
            waddr <= 10;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 7;
        end
        11:
        begin
            wdata <= 11;
            waddr <= 11;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 8;
        end
        12:
        begin
            wdata <= 12;
            waddr <= 12;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 9;
        end
        13:
        begin
            wdata <= 13;
            waddr <= 13;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 10;
        end
        14:
        begin
            wdata <= 14;
            waddr <= 14;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 11;
        end
        15:
        begin
            wdata <= 15;
            waddr <= 15;
            i <= i + 1 ;
            wclken <= 1'b1;
            raddr <= 12;
        end
        16:
        begin
            wdata <= 0;
            waddr <= 0;
            i <= i + 1 ;
            wclken <= 1'b0;
            raddr <= 13;
        end
        17:
        begin
            wdata <= 0;
            waddr <= 0;
            i <= i + 1 ;
            wclken <= 1'b0;
            raddr <= 14;
        end
        18:
        begin
            wdata <= 0;
            waddr <= 0;
            i <= i  ;
            wclken <= 1'b0;
            raddr <= 15;
        end

        endcase
    end
end


//------------------------------------------------------------

wire                       wfull ;
assign wfull = 0;

//------------------------------------------------------------

wire [DATASIZE-1 : 0] rdata;

fifomem #(
    .DATASIZE (8),       //Memory data word width
    .ADDRSIZE (4))      //Number of mem address bits       depth = 16
 U0 (
    .wdata(wdata),
    .waddr(waddr),
    .wclken(wclken),
    .wfull(wfull),
    .wclk(clk),
    .raddr(raddr),
    .rdata(rdata)
 );



endmodule




/*

add_force {/testbench/clk} -radix hex {1 0ns} {0 50000ps} -repeat_every 100000ps
add_force {/testbench/rst} -radix hex {1 0ns} {0 200ns}



*/

仿真波形圖：

從RAM讀出來的數據會比給定的地址晚兩拍。

使用仿順序操做來寫testbench也是極好的。