Testbenches Architecture

File structure of a project

Tip

In testbenches/ip/base/ you can find a test bench base design.

Project files for test benches

  • library — common files that are used in many projects

    • drivers — drivers and APIs used for controlling IPs as well as VIPs; these modules can use register map files, VIPs and other APIs

    • regmaps — register map files created for simulations based on the HDL IP register maps along with a couple of utility files; these are macro functions that are used to access a specific IP’s register’s field in a given variable that is passed to these functions

    • utilities — common scripts, modules and macros that are used for testbench design and environment creation

    • vip — ADI verification IPs (VIP) and additional auxiliary classes which are vendor specific

  • scripts — used for creating and running the testbenches

  • testbenches

    • cfgs — projects might have various parameters that can only be set during project creation, these parameters are set in one of these configuration files and can be passed to the simulation environment; they might also contain parameters that aid in building various block designs

    • tests — main simulation files, they control and monitor the DUT(s)

    • waves — waveforms for various configuration options (only used in GUI mode)

    • Makefile — lists the required System Verilog files, Tcl scripts, libraries used, and configuration-test_program combinations (if it’s the case, otherwise all configurations run one and the same default test program)

    • system_project.tcl — creates the project, the base block design based on the test_harness_system_bd and sets up a couple of definitions for the environment and test program

    • system_bd.tcl — adds the DUT(s) to the block design with the configuration files (even if no configuration parameter is used, a configuration file must exist)

    • system_tb.sv — connects the block design with the test program

Creating a new testbench

  • Create the Makefile and list all of the currently known dependencies

  • Create the system_project.tcl script and add the currently known simulation dependencies there as well

  • Create at least one configuration file (it can be left empty)

  • Create the system_bd.tcl script, which creates the block design (consider using Verification IPs as these are created to make testing easier and facilitates faster testbench bring-up as well as less bugs in general)

  • Create the system_tb.sv file that connects the testbench with the block design

  • Consider creating classes that encapsulate the variables and functions, so it can be used in other testbenches

  • Create the test_program.sv to run the simulation

  • Update the Makefile and system_project.tcl with the new dependencies if needed.

Adding a new configuration to a test bench

Note

Simple, all of the configurations are compatible with all of the test programs.

Requirements:

  • New configuration doesn’t change the connections between the block design and the test program.

  • Test program can be used with the new configuration without modifications.

Process:

  • Create a new configuration in cfg folder.

  • Check if the Makefile automatically includes the newly created configuration, otherwise add it to the list manually.

  • If a new parameter needs to be added, make sure all of the other configuration files are updated with the new parameter name and a new value as well

  • Test the configuration with the existing test program.

Adding a new test program to a test bench

Note

Simple, all of the configurations are compatible with all of the test programs.

Requirements:

  • Connections between the block design and the test program don’t change.

  • All of the existing configurations must be compatible with the new test program.

Process:

  • Create a new test program in tests folder.

  • Check if the Makefile automatically includes the newly created configuration, otherwise add it to the list manually.

  • Test the program with the existing configurations.

Creating a modified block design in the same project folder

Warning

Advanced, not all configurations are compatible with the test programs.

Requirements:

  • New configuration file(s) must be created for the new block design.

Process:

  • Create a new parameter that tells the system_bd.tcl what to build.

    • this parameter must be included in all of the existing and new configuration files;

    • if the design already has multiple variations of the block design, update the existing parameter with the new value which corresponds to the new block design

  • Modify the system_bd.tcl script to use the created parameter to create the old or new block design.

  • In system_tb.sv use the parameter to connect the new block design with a new test program.

  • Create the new test program.

  • In the Makefile, modify the TESTS list to not be automatically generated and add the test program:config options to the list that you want to run.

  • In the system_project.tcl add a switch that chooses between the test programs based on the parameter.

  • Write and test the new test program.