UVM learning - object attribute of UVM phase

UVM Objection

effect

1、 control taskphase Operation and termination of
2、 Synchronize the various component Homonymous task phase

Code example

Example 1

stay Last blog On the basis of driver The code of , Then run the simulation .

class my_driver extends uvm_driver #(my_transaction);

    `uvm_component_utils(my_driver)

    function new(string name = "my_driver", uvm_component parent);
        super.new(name, parent);
    endfunction

    virtual task reset_phase(uvm_phase phase);
        phase.raise_objection(this);
        #100;
        `uvm_info("DRV_RESET_PHASE", "Now driver reset the DUT...", UVM_MEDIUM);
        phase.drop_objection(this);
    endtask

    virtual task configure_phase(uvm_phase phase);
        phase.raise_objection(this);
        #100;
        `uvm_info("DRV_CONFIGURE_PHASE", "Now driver config the DUT...", UVM_MEDIUM);
        phase.drop_objection(this);
    endtask

    virtual task run_phase(uvm_phase phase);
        # 3000;
        forever begin
            seq_item_port.get_next_item(req);
            `uvm_info("DRV_RUN_PHASE", req.sprint(), UVM_MEDIUM)
            #100;
            seq_item_port.item_done();
        end
    endtask

endclass

reset_phase Not in the middle raise and drop objection, Run the simulation , As can be seen from the printed information ,reset_phase The statement in is not executed .

stay reset_phase Medium plus raise and drop objection after ,reset phase Normal execution of the statement .

There are no time statements that consume simulation time phase Can be executed normally , Part of the above code comments is as follows , It can also be executed normally .

virtual task reset_phase(uvm_phase phase);
        // phase.raise_objection(this);
        // #100;
        `uvm_info("DRV_RESET_PHASE", "Now driver reset the DUT...", UVM_MEDIUM);
        // phase.drop_objection(this);
    endtask

Be careful

1、Objection about task phase It makes sense , control task phase Operation and termination of .
2、 You must execute statements that consume simulation time raise objection
3、 stay task phase At the end drop objection.
4、 In a component One of the task phase in raise and drop objection It will affect others component Of the same name task phase.
5、 The suggestion is in every task phase Zhongdu raise and drop objection once .

Usage principle

1、raise and drop objection Use in pairs .
2、 Try to task phase Use raise objection and drop objection.
3、 Do not use in infinite loops raise objection and drop objection.
4、 Every phase Try to use it only once .
5、raise objection Before the time statement that consumes simulation time .