UVM virtual sequencer type cast fail from m_sequencer to p_sequencer

[reedzhu]

We encounter a simulation error as following when porting OVM to UVM:

In our testbench we use a parameter virtual sequencer which includes several sequencers, and a parameter virtual sequence which is the base class of various sub virtual sequencers.

We use `uvm_declare_p_sequencer(pcie_virtual_sequencer #(IF_PARAMS)) in the base virtual sequence(pcie_virtual_seq_base) to declear p_sequencer. But when simulation starts there is an error reported as following:

UVM_FATAL uvm_test_top.env.virtual_sequencer@@<unknown> [DCLPSQ] xxx::pcie_virtual_seq_base.m_set_p_sequencer uvm_test_top.env.virtual_sequencer.<unknown> Error casting p_sequencer, please verify that this sequence/sequence item is intended to execute on this type of sequencer

It seems the member object m_sequencer of pcie_virtual_seq_base can’t be converted to the parameter virtual sequencer pcie_virtual_sequencer.

The code is OK in OVM version. And I changed some items for UVM:

1. replace `uvm_sequencer_utils by `uvm_component_utils

2. remove `uvm_update_sequence_lib

3. replace set_config_string("*", "default_sequence".... by uvm_config_db#(uvm_object_wrapper)(..

In test case, I create a sub-sequence driverd from pcie_virtual_seq_base and use req.start() to launch tese in run_phase.

could anyone give me some advise? Thanks!

Edited May 3, 2011 by reedzhu

[uwes]

hi,

you can check in the GUI the types of m_sequencer and p_sequencer and see if there is a mismatch in the parameter set. apart from this you would need to provide more details about your sequencer types/instances etc.

/uwe