Handling input to output delay in Monitor sampling

UVM
,
3

In reply to uvmsd:

Using 2 analysis ports (one for input, one for output), it will be no problem. But you need to create different port using `uvm_analysis_imp_decl macro, then you will have 2 different write method to handle input/output trans.


`uvm_analysis_imp_decl(_input)
`uvm_analysis_imp_decl(_output)
class scoreboard extended uvm_socreboard;
   uvm_analysis_imp_input#(spi_seq_item , scoreboard) input_export_m;
   uvm_analysis_imp_output#(spi_seq_item , scoreboard) output_export_m;

   ...

   function void write_input(spi_seq_item trans);
     // Collect input trans
   endfunction : write_input

  function void write_output(spi_seq_item trans);
     // Collect output trans
   endfunction : write_output
endclass

However, if you want to handle 1 transaction including input and output data. There will have the way, all you need to do is saving the transaction until you have enough information.
For example:


class monitor extends uvm_monitor;
  spi_seq_item items[$];
  virtual task run_phase(uvm_phase phase);
    super.run_phase(phase);
    fork
      forever begin
        @( spi_vif.spi_cb);   
        if ( spi_vif.reset == 1) begin
          spi_seq_item seq_item_collected = new;
          seq_item_collected.mosi_in = spi_vif.mosi_in;
          items.push_back(seq_item_collected);
        end  // if reset   
      end //forever
      forever begin
        @( spi_vif.spi_cb);   
        if ( spi_vif.reset == 1) begin
          @( spi_vif.spi_cb);
          if(items.size() > 0) begin
            spi_seq_item seq_item_collected = items.pop_front();
            seq_item_collected.sr = (spi_vif.spi_cb.sr); 
            //TLM fifo   
            trans_collected_port.write(seq_item_collected);
          end
          else begin
            `uvm_error("MON", "Unexpected output without input")
          end
        end  // if reset   
      end //forever
    join
  endtask : run_phase

Idea: Save the transaction to a queue when you collect input, restore the transaction from the queue to collect output.