# Sequencer seems to generate seq items during startup

**URL:** <https://verificationacademy.com/forums/t/sequencer-seems-to-generate-seq-items-during-startup/28979>\
**Category:** OVM\
**Tags:** OVM\
**Created:** [December 2, 2013, 5:07pm UTC](https://verificationacademy.com/forums/t/sequencer-seems-to-generate-seq-items-during-startup/28979 "2013-12-02T17:07:42Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![frodus](https://verificationacademy.com/forums/letter_avatar_proxy/v4/letter/f/e95f7d/32.png) [@frodus](https://verificationacademy.com/forums/u/frodus)\
**Post date:** [December 2, 2013, 5:07pm UTC](https://verificationacademy.com/forums/t/sequencer-seems-to-generate-seq-items-during-startup/28979/1 "2013-12-02T17:07:42Z")

</div>

Hi,

I’m currently trying to implement a very simple reset agent but for some reasons the implementation seem to generate a couple of sequences at the beginning of the simulation which I can’t explain.

The implementation of the sequencer is as followed:

```auto
class reset_sequencer extends ovm_sequencer #(reset_seq_item);
  // OVM automation macro for sequencers
  `ovm_sequencer_utils(reset_sequencer)
  // Constructor
  function new (string name="simple_sequencer", ovm_component parent);
    super.new(name, parent);
    `ovm_update_sequence_lib_and_item(reset_seq)
  endfunction : new
endclass

```

The Implementation of the driver code is:

```auto
class reset_driver extends ovm_driver #(reset_seq_item);
   // Resgister the reset_agent with the factory
   `ovm_component_utils(reset_driver)

   typedef virtual reset_if t_if;
   virtual reset_if virtual_if;
   
   // define local parameter
   parameter HI=1'b1; // Shorthand bit high
   parameter LO=1'b0; // Shorthand bit low
   
   reg useTRST = 1; // use TRST for resetting RESET
   
   function new (string name, ovm_component parent);
      super.new(name, parent);
   endfunction // new

   function void build();
      ovm_object tmp;
      vintf #(t_if) v;

      super.build();
      if(!get_config_object("virtual_reset_interface", tmp, 0)) begin
         print_config_settings();
         ovm_report_error("build", "no virtual interface available");
      end
      else begin
         if(!$cast(v, tmp)) begin
            ovm_report_error("build", "virtual interface is incorrect type");
         end
         else begin
            virtual_if = v.m_vif;
         end
      end 
   endfunction

   task run();
      pull_reset();
      forever begin
         seq_item_port.get_next_item(req);
         req.print();
         pull_reset();
         seq_item_port.item_done();
      end
      $display("Reset Driver run task completed. %m", $time);
      
   endtask // run
   
   // initialize RESET access
   task pull_reset();
      $display("System reset activated, reseting device. %m", $time);
      virtual_if.RESET_N = LO;
      #5ns; 
      virtual_if.RESET_N = HI;
      #5ns; 
   endtask // reset_init

endclass

```

If I start my simulation I do get a random amount of “req” which leads to the following output:

```auto
# ----------------------------------------------------------------------
# Name Type Size Value
# ----------------------------------------------------------------------
# req reset_seq_item - req@759
# reset_active_level integral 1 'h0
# depth int 32 'd4
# parent sequence string 83 ovm_test_top.env.re+
# sequencer string 38 ovm_test_top.env.re+
# ----------------------------------------------------------------------
# System reset activated, reseting device. jtag_pkg.reset_driver.pull_reset 10000
# ----------------------------------------------------------------------
# Name Type Size Value
# ----------------------------------------------------------------------
# req reset_seq_item - req@1231
# reset_active_level integral 1 'h0
# depth int 32 'd4
# parent sequence string 83 ovm_test_top.env.re+
# sequencer string 38 ovm_test_top.env.re+
# ----------------------------------------------------------------------
# System reset activated, reseting device. jtag_pkg.reset_driver.pull_reset 21000
# ----------------------------------------------------------------------
# Name Type Size Value
# ----------------------------------------------------------------------
# req reset_seq_item - req@1239
# reset_active_level integral 1 'h0
# depth int 32 'd4
# parent sequence string 83 ovm_test_top.env.re+
# sequencer string 38 ovm_test_top.env.re+
# ----------------------------------------------------------------------
# System reset activated, reseting device. jtag_pkg.reset_driver.pull_reset 32000
# ----------------------------------------------------------------------
# Name Type Size Value
# ----------------------------------------------------------------------
# req reset_seq_item - req@1247
# reset_active_level integral 1 'h0
# depth int 32 'd4
# parent sequence string 83 ovm_test_top.env.re+
# sequencer string 38 ovm_test_top.env.re+
# ----------------------------------------------------------------------
# System reset activated, reseting device. jtag_pkg.reset_driver.pull_reset 43000
# ----------------------------------------------------------------------
# Name Type Size Value
# ----------------------------------------------------------------------
# req reset_seq_item - req@1255
# reset_active_level integral 1 'h0
# depth int 32 'd4
# parent sequence string 83 ovm_test_top.env.re+
# sequencer string 38 ovm_test_top.env.re+
# ----------------------------------------------------------------------
# System reset activated, reseting device. jtag_pkg.reset_driver.pull_reset 54000
# ----------------------------------------------------------------------

```

I’m using Questa 6.4c (legacy project) and OVM 2.0.1.

Any hint or tip how to debug this would really be appreciated.

Thanks,

Frodus

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<div class="post-metadata">

**Author:** ![frodus](https://verificationacademy.com/forums/letter_avatar_proxy/v4/letter/f/e95f7d/32.png) [@frodus](https://verificationacademy.com/forums/u/frodus)\
**Post date:** [December 3, 2013, 9:24am UTC](https://verificationacademy.com/forums/t/sequencer-seems-to-generate-seq-items-during-startup/28979/2 "2013-12-03T09:24:19Z")

</div>

Solved please close

---

<div class="post-metadata">

**Author:** ![dave\_59](https://verificationacademy.com/forums/user_avatar/verificationacademy.com/dave_59/32/4499_2.png) [@dave\_59](https://verificationacademy.com/forums/u/dave_59)\
**Post date:** [December 3, 2013, 3:23pm UTC](https://verificationacademy.com/forums/t/sequencer-seems-to-generate-seq-items-during-startup/28979/3 "2013-12-03T15:23:50Z")

</div>

_In reply to [frodus](https://verificationacademy.com/forums/t/sequencer-seems-to-generate-seq-items-during-startup/28979/2):_

Frodus, can you share what the problem was? One of the reasons the sequence library was deprecated in the UVM was that people were not always aware how extra default sequences got started when they were explicitly started them as well. We recommend not using the sequence library at all and just using the `ovm_component_utils or `ovm\_object\_utils macros.