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[/] [tv80/] [trunk/] [env/] [env_io.v] - Blame information for rev 53

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1 2 ghutchis 
 
2 
module env_io (/*AUTOARG*/
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  // Outputs
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  DI,
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  // Inputs
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  clk, iorq_n, rd_n, wr_n, addr, DO
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  );
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  input clk;
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  input iorq_n;
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  input rd_n;
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  input wr_n;
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  input [7:0] addr;
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  input [7:0] DO;
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  inout [7:0] DI;
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  reg [7:0]    io_data;
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  reg [7:0]    str_buf [0:255];
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  reg          io_cs;
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  integer      buf_ptr, i;
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  reg [7:0]    timeout_ctl;
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  reg [15:0]   cur_timeout;
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  reg [15:0]   max_timeout;
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  reg [7:0]    int_countdown;
28 37 ghutchis 
  reg [7:0]    checksum;
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  reg [7:0]    ior_value;  // increment-on-read value
30 2 ghutchis 
 
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  assign       DI = (!iorq_n & !rd_n & io_cs) ? io_data : {8{1'bz}};
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  initial
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    begin
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      io_cs = 0;
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      buf_ptr = 0;
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      cur_timeout = 0;
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      max_timeout = 10000;
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      timeout_ctl = 1;
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      int_countdown = 0;
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    end
42 37 ghutchis 
 
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  always @*
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    begin
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      if (!iorq_n & !rd_n)
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        begin
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          io_cs = (addr[7:5] == 3'b100);
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          case (addr)
50 53 ghutchis 
            8'h82 : io_data = timeout_ctl;
51 37 ghutchis 
            8'h83 : io_data = max_timeout[7:0];
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            8'h84 : io_data = max_timeout[15:8];
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            8'h90 : io_data = int_countdown;
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            8'h91 : io_data = checksum;
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            8'h93 : io_data = ior_value;
57 41 ghutchis 
            8'h94 : io_data = {$random};
58 37 ghutchis 
            default : io_data = 8'hzz;
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          endcase // case(addr)
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        end // if (!iorq_n & !rd_n)
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    end // always @ *
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63 2 ghutchis 
  always @(posedge clk)
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    begin
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      if (!iorq_n & !wr_n)
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        case (addr)
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          8'h80 :
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            begin
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              case (DO)
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                1 : tb_top.test_pass;
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                2 : tb_top.test_fail;
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                3 : tb_top.dumpon;
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                4 : tb_top.dumpoff;
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                default :
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                  begin
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                    $display ("%t: ERROR   : Unknown I/O command %x", $time, DO);
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                  end
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              endcase // case(DO)
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            end // case: :...
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          8'h81 :
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            begin
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              str_buf[buf_ptr] = DO;
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              buf_ptr = buf_ptr + 1;
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              //$display ("%t: DEBUG   : Detected write of character %x", $time, DO);
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              if (DO == 8'h0A)
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                begin
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                  $write ("%t: PROGRAM : ", $time);
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                  for (i=0; i<buf_ptr; i=i+1)
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                    $write ("%s", str_buf[i]);
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                  buf_ptr = 0;
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                end
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            end // case: 8'h81
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          8'h82 :
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            begin
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              timeout_ctl = DO;
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            end
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          8'h83 : max_timeout[7:0] = DO;
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          8'h84 : max_timeout[15:8] = DO;
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          8'h90 : int_countdown = DO;
111 37 ghutchis 
          8'h91 : checksum = DO;
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          8'h92 : checksum = checksum + DO;
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          8'h93 : ior_value = DO;
114 2 ghutchis 
        endcase // case(addr)
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    end // always @ (posedge clk)
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  always @(posedge clk)
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    begin
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      if (timeout_ctl[1])
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        cur_timeout = 0;
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      else if (timeout_ctl[0])
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        cur_timeout = cur_timeout + 1;
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      if (cur_timeout >= max_timeout)
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        begin
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          $display ("%t: ERROR   : Reached timeout %d cycles", $time, max_timeout);
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          tb_top.test_fail;
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        end
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    end // always @ (posedge clk)
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  always @(posedge clk)
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    begin
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      if (int_countdown == 1)
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        begin
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          tb_top.int_n  <= #1 1'b0;
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          int_countdown = 0;
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        end
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      else if (int_countdown > 1)
139 31 ghutchis 
        begin
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          int_countdown = int_countdown - 1;
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          tb_top.int_n  <= #1 1'b1;
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        end
143 2 ghutchis 
    end
144 
 
145 
endmodule // env_io

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