OVM sequencer :

Sequencer generates stimulus data and passes it to the driver. All sequencers should be derived from the ovm_sequence base class directly or indirectly. Sequencer have a TLM port which is connected to the driver. ovm_sequence base call is parameterized for request and respose item types.

So to create a sequencer to you need to :

• Derive a sequencer from the ovm_sequencer base class and specify the request and response type parameters
• Use `ovm_sequencer_utils and `ovm_update_sequence_lib_and_item to indicate the generated data item type and field desired automation

Connecting the Driver and Sequencer :

The driver and the sequencer are connected via TLM, with the driver’s seq_item_port connected
to the sequencer’s seq_item_export. elow). The sequencer produces data items to provide via the export. The driver consumes data items through its seq_item_port, and optionally provides responses. The component that contains the instances of the driver and sequencer makes the connection between them

Example :

OVM sequencer example :

// OVM sequencer example 
class mem_master_sequencer extends ovm_sequencer # (mem_transfer);

    protected virtual mem_if m_if;

    protected int master_id;

    `ovm_object_utils_begin (mem_master_sequencer)
        `ovm_field_int (master_id, OVM_ALL_ON)
    `ovm_object_utils_end

    `ovm_declare_sequence_lib

    // constructor
    function new (string name = "mem_master_sequencer", ovm_component parent = null) ;
        super.new (name, parent);
        `ovm_update_sequence_lib_and_item(mem_transfer)
    endfunction : new

    function void assign_vi (virtual interface mem_if m_if);
        this.m_if = m_if;
    endfunction : assign_vi

endclass : mem_master_sequencer

This Articles is written/submitted by puneet (Puneet Aggarwal). You can also contribute to Asicguru.com. Click here to start