Subversion Repositories eco32

//

// fms.v -- FM synthesizer

//

// NOTE: This is a fake module for now.

//       It allows writing directly to the DAC.

//

`timescale 1ns/10ps

`default_nettype none

module fms(clk, rst,

           stb, we, addr,

           data_in, data_out,

           ack,

           next, sample_l, sample_r);

    // internal interface

    input clk;

    input rst;

    input stb;

    input we;

    input [11:2] addr;

    input [31:0] data_in;

    output [31:0] data_out;

    output ack;

    // DAC controller interface

    input next;

    output [15:0] sample_l;

    output [15:0] sample_r;

  reg [31:0] value;

  reg value_needed;

  always @(posedge clk) begin

    if (rst) begin

      value[31:0] <= 32'h0;

      value_needed <= 0;

    end else begin

      if (stb & we & ~|addr[11:2]) begin

        value[31:0] <= data_in[31:0];

        value_needed <= 0;

      end else begin

        if (next) begin

          value_needed <= 1;

        end

      end

    end

  end

  assign data_out[31:0] = { 31'h0, value_needed };

  assign ack = stb;

  assign sample_l[15:0] = value[31:16];

  assign sample_r[15:0] = value[15:0];

endmodule