// Random Bitstream Generator
//
// Version 1a, 22 Nov 03
//
// Ken Kundert
//
// Downloaded from The Designer's Guide (www.designers-guide.org).
// Post any questions on www.designers-guide.org/Forum.

`include "disciplines.vams"

module bitStream (out);
    output out;
    electrical out;
    parameter real start = 0.0;
    parameter real period = 1.0;
    integer x;

    analog begin
	@(timer(start, period))
	    x = ($random >= 0) ? 1 : 0;
	V(out) <+ transition( x, 0.0, period/100.0 );
    end
endmodule


// This version support a seed parameter

module bitStream2 (out);
    output out;
    electrical out;
    parameter real start = 0.0;
    parameter real period = 1.0;
    parameter integer seed = 0;
    integer x, y;

    analog begin
	@(initial_step)
	    y = seed;
	@(timer(start, period))
	    x = ($random(y) >= 0) ? 1 : 0;
	V(out) <+ transition( x, 0.0, period/100.0 );
    end
endmodule