//------------------------------------------------------------------------------
// reverse_vector_tb.sv
// Konstantin Pavlov, pavlovconst@gmail.com
//------------------------------------------------------------------------------

// INFO ------------------------------------------------------------------------
// testbench for reverse_vector module


`timescale 1ns / 1ps

module reverse_vector_tb();

logic clk200;
initial begin
  #0 clk200 = 1;
  forever
    #2.5 clk200 = ~clk200;
end

logic rst;
initial begin
  #10.2 rst = 1;
  #5 rst = 0;
  //#10000;
  forever begin
    #9985 rst = ~rst;
    #5 rst = ~rst;
  end
end

logic nrst;
assign nrst = ~rst;

logic rst_once;
initial begin       // initializing non-X data before PLL starts
  #10.2 rst_once = 1;
  #5 rst_once = 0;
end
initial begin
  #510.2 rst_once = 1;    // PLL starts at 500ns, clock appears, so doing the reset for modules
  #5 rst_once = 0;
end

logic nrst_once;
assign nrst_once = ~rst_once;

logic [31:0] DerivedClocks;
ClkDivider #(
  .WIDTH( 32 )
) CD1 (
  .clk( clk200 ),
  .nrst( nrst_once ),
  .out( DerivedClocks[31:0] )
);

logic [31:0] E_DerivedClocks;
EdgeDetect ED1[31:0] (
  .clk( {32{clk200}} ),
  .nrst( {32{nrst_once}} ),
  .in( DerivedClocks[31:0] ),
  .rising( E_DerivedClocks[31:0] ),
  .falling(  ),
  .both(  )
);

logic [15:0] RandomNumber1;
c_rand RNG1 (
  .clk( clk200 ),
  .rst( rst_once ),
  .reseed( 1'b0 ),
  .seed_val( DerivedClocks[31:0] ),
  .out( RandomNumber1[15:0] )
);

logic start;
initial begin
  #0 start = 1'b0;
  #100.2 start = 1'b1;
  #5 start = 1'b0;
end

// Module under test ==========================================================

// odd width
logic [14:0] reversed1;
reverse_vector #(
  .WIDTH( 15 )         // WIDTH must be >=2
) RV1 (
  .in( RandomNumber1[14:0] ),
  .out( reversed1[14:0] )   // reversed bit order
);

// even width
logic [13:0] reversed2;
reverse_vector #(
  .WIDTH( 14 )         // WIDTH must be >=2
) RV2 (
  .in( reversed1[13:0] ),
  .out( reversed2[13:0] )   // reversed bit order
);

endmodule