uart1.v

这个是基于NIOS II的FPGA平台的一个CF卡的接口模块

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// synthesis translate_off
`timescale 1ns / 100ps
// synthesis translate_on
module uart1_log_module (
                          // inputs:
                           clk,
                           data,
                           strobe,
                           valid
                        );

  input            clk;
  input   [  7: 0] data;
  input            strobe;
  input            valid;


//synthesis translate_off
//////////////// SIMULATION-ONLY CONTENTS
   reg [31:0] text_handle; // for $fopen
   initial text_handle = $fopen ("C:/designs/cf_tests/to_nios_forum/std_cf_2c35/std_2C35_sim/uart1_log_module.txt");

   always @(posedge clk) begin
      if (valid && strobe) begin
	 // Send \n (linefeed) instead of \r (^M, Carriage Return)...
         $fwrite (text_handle, "%s", ((data == 8'hd) ? 8'ha : data));
	 // non-standard; poorly documented; required to get real data stream.
	 $fflush (text_handle);
      end
   end // clk


//////////////// END SIMULATION-ONLY CONTENTS

//synthesis translate_on


endmodule


module uart1_tx (
                  // inputs:
                   baud_divisor,
                   begintransfer,
                   clk,
                   clk_en,
                   do_force_break,
                   reset_n,
                   status_wr_strobe,
                   tx_data,
                   tx_wr_strobe,

                  // outputs:
                   tx_overrun,
                   tx_ready,
                   tx_shift_empty,
                   txd
                );

  output           tx_overrun;
  output           tx_ready;
  output           tx_shift_empty;
  output           txd;
  input   [  9: 0] baud_divisor;
  input            begintransfer;
  input            clk;
  input            clk_en;
  input            do_force_break;
  input            reset_n;
  input            status_wr_strobe;
  input   [  7: 0] tx_data;
  input            tx_wr_strobe;

  reg              baud_clk_en;
  reg     [  9: 0] baud_rate_counter;
  wire             baud_rate_counter_is_zero;
  reg              do_load_shifter;
  wire             do_shift;
  reg              pre_txd;
  wire             shift_done;
  wire    [  9: 0] tx_load_val;
  reg              tx_overrun;
  reg              tx_ready;
  reg              tx_shift_empty;
  wire             tx_shift_reg_out;
  wire    [  9: 0] tx_shift_register_contents;
  wire             tx_wr_strobe_onset;
  reg              txd;
  wire    [  9: 0] unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_in;
  reg     [  9: 0] unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_out;
  assign tx_wr_strobe_onset = tx_wr_strobe && begintransfer;
  assign tx_load_val = {{1 {1'b1}},
    tx_data,
    1'b0};

  assign shift_done = ~(|tx_shift_register_contents);
  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          do_load_shifter <= 0;
      else if (clk_en)
          do_load_shifter <= (~tx_ready) && shift_done;
    end


  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          tx_ready <= 1'b1;
      else if (clk_en)
          if (tx_wr_strobe_onset)
              tx_ready <= 0;
          else if (do_load_shifter)
              tx_ready <= -1;
    end


  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          tx_overrun <= 0;
      else if (clk_en)
          if (status_wr_strobe)
              tx_overrun <= 0;
          else if (~tx_ready && tx_wr_strobe_onset)
              tx_overrun <= -1;
    end


  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          tx_shift_empty <= 1'b1;
      else if (clk_en)
          tx_shift_empty <= tx_ready && shift_done;
    end


  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          baud_rate_counter <= 0;
      else if (clk_en)
          if (baud_rate_counter_is_zero || do_load_shifter)
              baud_rate_counter <= baud_divisor;
          else 
            baud_rate_counter <= baud_rate_counter - 1;
    end


  assign baud_rate_counter_is_zero = baud_rate_counter == 0;
  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          baud_clk_en <= 0;
      else if (clk_en)
          baud_clk_en <= baud_rate_counter_is_zero;
    end


  assign do_shift = baud_clk_en  && 
    (~shift_done) && 
    (~do_load_shifter);

  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          pre_txd <= 1;
      else if (~shift_done)
          pre_txd <= tx_shift_reg_out;
    end


  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          txd <= 1;
      else if (clk_en)
          txd <= pre_txd & ~do_force_break;
    end


  //_reg, which is an e_register
  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_out <= 0;
      else if (clk_en)
          unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_out <= unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_in;
    end


  assign unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_in = (do_load_shifter)? tx_load_val :
    (do_shift)? {1'b0,
    unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_out[9 : 1]} :
    unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_out;

  assign tx_shift_register_contents = unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_out;
  assign tx_shift_reg_out = unxshiftxtx_shift_register_contentsxtx_shift_reg_outxx5_out[0];


endmodule


module uart1_rx_stimulus_source_character_source_rom_module (
                                                              // inputs:
                                                               clk,
                                                               incr_addr,
                                                               reset_n,

                                                              // outputs:
                                                               new_rom,
                                                               q,
                                                               safe
                                                            );

  parameter POLL_RATE = 100;


  output           new_rom;
  output  [  7: 0] q;
  output           safe;
  input            clk;
  input            incr_addr;
  input            reset_n;

  reg     [ 10: 0] address;
  reg              d1_pre;
  reg              d2_pre;
  reg              d3_pre;
  reg              d4_pre;
  reg              d5_pre;
  reg              d6_pre;
  reg              d7_pre;
  reg              d8_pre;
  reg              d9_pre;
  reg     [  7: 0] mem_array [1023: 0];
  reg     [ 31: 0] mutex [  1: 0];
  reg              new_rom;
  reg              pre;
  wire    [  7: 0] q;
  wire             safe;

//synthesis translate_off
//////////////// SIMULATION-ONLY CONTENTS
  assign q = mem_array[address];
  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
        begin
          d1_pre <= 0;
          d2_pre <= 0;
          d3_pre <= 0;
          d4_pre <= 0;
          d5_pre <= 0;
          d6_pre <= 0;
          d7_pre <= 0;
          d8_pre <= 0;
          d9_pre <= 0;
          new_rom <= 0;
        end
      else if (1)
        begin
          d1_pre <= pre;
          d2_pre <= d1_pre;
          d3_pre <= d2_pre;
          d4_pre <= d3_pre;
          d5_pre <= d4_pre;
          d6_pre <= d5_pre;
          d7_pre <= d6_pre;
          d8_pre <= d7_pre;
          d9_pre <= d8_pre;
          new_rom <= d9_pre;
        end
    end


   reg        safe_delay;
   reg [31:0] poll_count;
   reg [31:0] mutex_handle;
   wire       interactive = 1'b0 ; // '
   assign     safe = (address < mutex[1]);

   initial poll_count = POLL_RATE;

   always @(posedge clk or negedge reset_n) begin
      if (reset_n !== 1) begin
         safe_delay <= 0;
      end else begin
         safe_delay <= safe;
      end
   end // safe_delay

   always @(posedge clk or negedge reset_n) begin
      if (reset_n !== 1) begin  // dont worry about null _stream.dat file
         address <= 0;
         mem_array[0] <= 0;
         mutex[0] <= 0;
         mutex[1] <= 0;
         pre <= 0;
      end else begin            // deal with the non-reset case
         pre <= 0;
         if (incr_addr && safe) address <= address + 1;
         if (mutex[0] && !safe && safe_delay) begin
            // and blast the mutex after falling edge of safe if interactive
            if (interactive) begin
               mutex_handle = $fopen ("C:/designs/cf_tests/to_nios_forum/std_cf_2c35/std_2C35_sim/uart1_input_data_mutex.dat");
               $fdisplay (mutex_handle, "0");
               $fclose (mutex_handle);
               // $display ($stime, "\t%m:\n\t\tMutex cleared!");
            end else begin
               // sleep until next reset, do not bash mutex.
               wait (!reset_n);
            end
         end // OK to bash mutex.
         if (poll_count < POLL_RATE) begin // wait
            poll_count = poll_count + 1;
         end else begin         // do the interesting stuff.
            poll_count = 0;
            $readmemh ("C:/designs/cf_tests/to_nios_forum/std_cf_2c35/std_2C35_sim/uart1_input_data_mutex.dat", mutex);
            if (mutex[0] && !safe) begin
            // read stream into mem_array after current characters are gone!
               // save mutex[0] value to compare to address (generates 'safe')
               mutex[1] <= mutex[0];
               // $display ($stime, "\t%m:\n\t\tMutex hit: Trying to read %d bytes...", mutex[0]);
               $readmemh("C:/designs/cf_tests/to_nios_forum/std_cf_2c35/std_2C35_sim/uart1_input_data_stream.dat", mem_array);
               // bash address and send pulse outside to send the char:
               address <= 0;
               pre <= -1;
            end // else mutex miss...
         end // poll_count
      end // reset
   end // posedge clk


//////////////// END SIMULATION-ONLY CONTENTS

//synthesis translate_on


endmodule


module uart1_rx_stimulus_source (
                                  // inputs:
                                   baud_divisor,
                                   clk,
                                   clk_en,
                                   reset_n,
                                   rx_char_ready,
                                   rxd,