Subversion Repositories 1g_ethernet_dpi

//------------------------------------------------------------------------------
// File       : tri_mode_ethernet_mac_0_example_design_resets.v
// Author     : Xilinx Inc.
// -----------------------------------------------------------------------------
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// -----------------------------------------------------------------------------
// Description:  This block generates fully synchronous resets for each clock domain
`timescale 1 ps/1 ps
 
module tri_mode_ethernet_mac_0_example_design_resets
   (
   // clocks
   input          s_axi_aclk,
   input          gtx_clk,
 
   // asynchronous resets
   input          glbl_rst,
   input          reset_error,
   input          rx_reset,
   input          tx_reset,
 
   input          dcm_locked,
 
   // synchronous reset outputs
 
   output         glbl_rst_intn,
 
   output   reg   gtx_resetn = 0,
 
   output   reg   s_axi_resetn = 0,
   output         phy_resetn,
   output   reg   chk_resetn = 0
   );
 
// define internal signals
    reg           s_axi_pre_resetn = 0;
    wire          s_axi_reset_int;
 
    reg           gtx_pre_resetn = 0;
    wire          gtx_clk_reset_int;
 
    reg           chk_pre_resetn = 0;
    wire          chk_reset_int;
    wire          dcm_locked_sync;
    reg           phy_resetn_int;
    reg  [5:0]    phy_reset_count;
 
  //----------------------------------------------------------------------------
  // Synchronise the async dcm_locked into the gtx_clk clock domain
  //----------------------------------------------------------------------------
  tri_mode_ethernet_mac_0_sync_block dcm_sync (
     .clk              (gtx_clk),
     .data_in          (dcm_locked),
     .data_out         (dcm_locked_sync)
  );
 
 
  //----------------------------------------------------------------------------
  // Generate resets required for the fifo side signals etc
  //----------------------------------------------------------------------------
  // in each case the async reset is first captured and then synchronised
 
  //---------------
  // global reset
   tri_mode_ethernet_mac_0_reset_sync glbl_reset_gen (
      .clk              (gtx_clk),
      .enable           (dcm_locked_sync),
      .reset_in         (glbl_rst),
      .reset_out        (glbl_rst_int)
   );
 
   assign glbl_rst_intn = !glbl_rst_int;
 
 
 
  //---------------
  // AXI-Lite reset
   tri_mode_ethernet_mac_0_reset_sync axi_lite_reset_gen (
      .clk              (s_axi_aclk),
      .enable           (phy_resetn_int),
      .reset_in         (glbl_rst),
      .reset_out        (s_axi_reset_int)
   );
 
   // Create fully synchronous reset in the s_axi clock domain.
   always @(posedge s_axi_aclk)
   begin
     if (s_axi_reset_int) begin
       s_axi_pre_resetn <= 0;
       s_axi_resetn     <= 0;
     end
     else begin
       s_axi_pre_resetn <= 1;
       s_axi_resetn     <= s_axi_pre_resetn;
     end
   end
 
  //---------------
 
  // gtx_clk reset
 
   tri_mode_ethernet_mac_0_reset_sync gtx_reset_gen (
 
      .clk              (gtx_clk),
 
      .enable           (dcm_locked_sync),
      .reset_in         (glbl_rst || rx_reset || tx_reset),
 
      .reset_out        (gtx_clk_reset_int)
 
   );
 
 
   // Create fully synchronous reset in the gtx_clk domain.
   always @(posedge gtx_clk)
   begin
     if (gtx_clk_reset_int) begin
       gtx_pre_resetn  <= 0;
       gtx_resetn      <= 0;
     end
     else begin
       gtx_pre_resetn  <= 1;
       gtx_resetn      <= gtx_pre_resetn;
     end
   end
 
  //---------------
  // data check reset
   tri_mode_ethernet_mac_0_reset_sync chk_reset_gen (
 
      .clk              (gtx_clk),
 
      .enable           (dcm_locked_sync),
      .reset_in         (glbl_rst || reset_error),
      .reset_out        (chk_reset_int)
   );
 
 
   // Create fully synchronous reset in the gtx_clk domain.
   always @(posedge gtx_clk)
 
   begin
     if (chk_reset_int) begin
       chk_pre_resetn  <= 0;
       chk_resetn      <= 0;
     end
     else begin
       chk_pre_resetn  <= 1;
       chk_resetn      <= chk_pre_resetn;
     end
   end
 
 
   //---------------
   // PHY reset
   // the phy reset output (active low) needs to be held for at least 10x25MHZ cycles
   // this is derived using the 125MHz available and a 6 bit counter
   always @(posedge gtx_clk)
   begin
      if (glbl_rst_int) begin
         phy_resetn_int <= 0;
         phy_reset_count <= 0;
      end
      else begin
         if (!(&phy_reset_count)) begin
            phy_reset_count <= phy_reset_count + 1;
         end
         else begin
            phy_resetn_int <= 1;
         end
      end
   end
 
   assign phy_resetn = phy_resetn_int;
 
endmodule