Connecting monitor and scoreboard in UVM

Question

I am constructing the UVM testbench to verify a simple design. I have learnt that scoreboard will usually be outside the agent. I want my scoreboard to be inside the agent as I have only one agent in the system. Now, in my agent, I am trying to connect monitor and scoreboard. I want to know if there is a way to connect without using fifo.

Here are my code snippets

class my_monitor extends uvm_monitor;
  `uvm_component_utils(my_monitor)
  uvm_analysis_port #(input_seq_item) ap_port;
  input_seq_item mon_item;
  ....
endclass

class my_scoreboard extends uvm_scoreboard;
  `uvm_component_utils(my_scoreboard)
  uvm_analysis_export #(input_seq_item) ap_port_sb;
  ...
endclass

class agent extends uvm_agent;
  `uvm_component_utils(agent)
  sequencer sqr;
  my_driver drv;
  my_sequence seq;
  my_monitor mon;
  my_scoreboard sb;
  ...
    function void connect_phase(uvm_phase phase);
    super.connect_phase(phase);
    drv.seq_item_port.connect(sqr.seq_item_export);
    mon.ap_port.connect(sb.ap_port_sb);
  endfunction
  ...
endclass

I am getting the following error

# KERNEL: UVM_INFO @ 0: reporter [RNTST] Running test test...
# KERNEL: UVM_ERROR @ 0: uvm_test_top.env.sb.ap_port_sb [Connection Error] connection count of 0 does not meet required minimum of 1
# KERNEL: UVM_FATAL @ 0: reporter [BUILDERR] stopping due to build errors
# KERNEL: UVM_INFO /home/build/vlib1/vlib/uvm-1.2/src/base/uvm_report_server.svh(855) @ 0: reporter [UVM/REPORT/SERVER] 

Can anyone help me with this?

Thanks in advance

Answer 1

The problem is you left your scoreboard analysis export hanging, but it needs to be connected to an imp port. If you're familiar with SystemC, an imp port doesn't have a direct equivalent. An import basically is a termination point of a TLM analysis connection. The imp port then forwards the calls to the component that instantiates it.

Change your code to uvm_analysis_imp #(...) and declare a write(input_seq_item ite) function for it to call and everything should work.