Subversion Repositories cdc_ufifo

module graycntr (gray, clk, inc, rst_n, gnext);

parameter lpm_width = 4;

output [lpm_width-1:0] gray;

output [lpm_width-1:0] gnext;

input clk, inc, rst_n;

reg [lpm_width-1:0] gnext, gray, bnext, bin;

integer i;

always @(posedge clk or negedge rst_n)

    if (!rst_n)

        gray <= 0;

    else if (inc)

        gray <= gnext;

always @(gray or inc) begin

    for (i=0; i<lpm_width; i=i+1)

        bin[i] = ^(gray>>i);

    bnext = bin+1'b1;

    gnext = (bnext>>1) ^ bnext;

end

endmodule