xsync_fpge_v2/source/src/zutils/zsimple_pll.v

module zsimple_pll (
    input clk,   //!clock input
    input rst_n, //!asynchronous reset input, low active

    input              insignal,             //!输入信号
    input  wire [31:0] trigger_eage_type,
    input  wire [31:0] freq_detect_bias,     //! 频率偏差计数
    input  wire [31:0] freq_division,
    input  wire [31:0] freq_multiplication,
    input  wire        polarity_ctrl,
    input  wire        cfg_change,
    output wire        outsignal
);

  //
  //
  //insignal
  //      ----->
  //            insignal_trigger_sig
  //                             ------->
  //                                    insignal_division
  //                                                -------->
  //                                                       insignal_multiplication



  wire insignal_rising_edge;  //! 输入信号上升沿
  wire insignal_falling_edge;  //! 输入信号下降沿
  reg  insignal_trigger_sig;  //! 触发信号
  wire module_reset;  //! 模块内部复位信号

  reg  insignal_division;  //! 输入信号分频后的信号
  reg  insignal_multiplication;  //! 输入信号倍频后的信号
  reg  insignal_pluse_width_modulation;  //! 输入信号脉宽调制后的信号


  zutils_edge_detecter edge_detecter (
      .clk                   (clk),
      .rst_n                 (rst_n),
      .in_signal             (insignal),
      .in_signal_rising_edge (insignal_rising_edge),
      .in_signal_falling_edge(insignal_falling_edge)
  );


  always @(*) begin
    case (trigger_eage_type)
      0:       insignal_trigger_sig <= insignal_rising_edge;
      1:       insignal_trigger_sig <= insignal_falling_edge;
      2:       insignal_trigger_sig <= insignal_rising_edge | insignal_falling_edge;
      default: insignal_trigger_sig <= insignal_rising_edge;
    endcase
  end

  // assign insignal_trigger_sig = trigger_eage_type ? insignal_rising_edge : insignal_falling_edge;
  assign module_reset = !rst_n || cfg_change;

  // 分频
  reg [31:0] insignal_division_cnt;
  always @(posedge clk or posedge module_reset) begin
    if (module_reset) begin
      insignal_division_cnt <= 0;
      insignal_division     <= 0;
    end else begin
      if (insignal_trigger_sig) begin
        if (insignal_division_cnt >= freq_division) begin
          insignal_division_cnt <= 0;
          insignal_division     <= 1;
        end else begin
          insignal_division_cnt <= insignal_division_cnt + 1;
        end
      end else begin
        insignal_division <= 0;
      end
    end
  end


  wire [31:0] insignal_multiplication_freq_cnt;
  wire        pluse_width_cnt_lock;

  zutils_freq_detector_v2 freq_detector (
      .clk                 (clk),
      .rst_n               (rst_n),
      .freq_detect_bias    (freq_detect_bias),
      .pluse_input         (insignal_division),
      .pluse_width_cnt     (insignal_multiplication_freq_cnt),
      .pluse_width_cnt_lock(pluse_width_cnt_lock)
  );


  reg [31:0] multiplication_cnt;
  reg [31:0] multiplication_state;
  reg [31:0] gen_pluse_cnt;

  always @(posedge clk or posedge module_reset) begin
    if (module_reset || !pluse_width_cnt_lock) begin
      multiplication_cnt      <= 0;
      multiplication_state    <= 0;
      gen_pluse_cnt           <= 0;
      insignal_multiplication <= insignal_division;
    end else begin
      case (multiplication_state)
        0: begin
          gen_pluse_cnt           <= 0;
          multiplication_cnt      <= 0;
          insignal_multiplication <= insignal_division;

          if (pluse_width_cnt_lock) begin
            multiplication_state <= 1;
          end
        end
        1: begin
          if (insignal_division) begin
            multiplication_state    <= 2;
            gen_pluse_cnt           <= 0;
            insignal_multiplication <= 1;
            multiplication_cnt      <= 0;
          end
        end
        2: begin
          if (multiplication_cnt < insignal_multiplication_freq_cnt >> 1) begin
            multiplication_cnt      <= multiplication_cnt + freq_multiplication + 1;
            insignal_multiplication <= 1;
          end else if ((multiplication_cnt + freq_multiplication + 2) >= insignal_multiplication_freq_cnt) begin
            gen_pluse_cnt           <= gen_pluse_cnt + 1;
            multiplication_cnt      <= 0;
            insignal_multiplication <= 1;
            gen_pluse_cnt           <= gen_pluse_cnt + 1;
          end else begin
            if (gen_pluse_cnt >= freq_multiplication) begin
              multiplication_state    <= 1;
              insignal_multiplication <= 0;
              multiplication_cnt      <= 0;
            end else begin
              multiplication_cnt      <= multiplication_cnt + freq_multiplication + 1;
              insignal_multiplication <= 0;
            end
          end
        end
        default: begin
          multiplication_state <= 0;
        end
      endcase
    end
  end


  assign outsignal = insignal_multiplication ^ polarity_ctrl;
endmodule