OVM/UVM : A Practical Tutorial Using System Verilog

-Aviral Mittal

Note: UVM source code for this tutorial is available. Click here and fill your details, to receive Source Code download link.


M(B)illion Dollar Question:
Why? why OVM/UVM

One may argue, what is the need of OVM/UVM? why OVM/UVM Exists?
Traditionally, test benches were written using VHDL or Verilog. The concept was simple, drive inputs to DUT,
Observe Outputs, check if Outputs are as expected. However, this model could not keep pace with the

growing complexity of systems and growing complexity of SoC integration.

1.       The key question is: How and when would an engineer may declare that verification is complete?

2.       The other problem is Re-use? How do we re-use testbenches?

3.       And last and certainly not the least BUGS? Is your Verification Env good enough to catch bugs?

4.       Has all the possible combination of inputs been created by the verification?


Tutorial Organization:
The tutorial starts with concise theory, followed by some practicals. If you are smart enough with the
theory part, keep on clicking 'Next' at bottom, till you see practicals.
The tutorial makes references to AHB protocol. Its important for the reader to understand AHB protocol.
A copy of the AHB protocol spec can be found here
. It is recommended that the user makes himself familiar
with the AHB protocol, to be able to make most out of this tutorial.

Tutorial Objective:
The objective of this tutorial is to let the user be able to write his/her UVM compliant test-benches
as soon as possible. The tutorial wont deal with what Object Oriented programming is, it wont
deal with the theory of UVM. It will just let the user understand the structure of UVM compliant
test-benches (or test environments) and what all is needed to be able to write compile and simulate
a UVM compliant test bench.

Introduction:

OVM/UVM is a systematic and standardized way to write Test Bench or Test Environments for IPs, Subsystems etc.
The VLSI Industry has 2 principal languages to write advanced test benches and test environments.
One is Specman ‘e’ and the other is SystemVerilog.
Though Specman ‘e’ was the first language invented specifically for verification,
SystemVerilog arrived late, and it did take concepts from Specman ‘e’.

To be able to understand OVM/UVM concepts, its important to understand the following

1.       Concept of Constrained Random verification

2.       Concept of Interfaces

3.       Concept of Transaction level Modelling (TLM)






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KeyWords: OVM, UVM, SystemVerilog, Constrained Random Verification, Transaction Level Modelling.