UVM e Verification Tutorial using Specman
Aviral Mittal


1. Introduction/Preface:

This Tutorial is a very simple explanation of the UVM methodology, taking Specman 'e' as an example language.
The concepts presented here, can easily be ported into System Verilog.
The object here is to explain why this UVM UVM di :), not have a discussion over System Verilog Vs Specman 'e'.


Issues addressed by UVM/OVM.
The rapidly growing complexity of SoCs and subsystems pose a substantial verification challenge. Conventional
way of writing testbenches, which is also termed as directed test writing approach is proving to be inadequate
to be able to find bugs in these complex systems. "Constrained Random" Stimulus generation is understood
to be able to address this issue. It is understood that using constrained random stimulus, it’s easier to find bugs with
less efforts. This is the primary way of generating stimulus in UVM/OVM methodology.
UVM/OVM methodology provides a standard infrastructure to develop a reuseable testbench.It is understood that an
UVM/OVM compliant test environment can easily be ported across various projects.
There are two aspects of the UVM/OVM testbench, one is the development of the testbench/test environment
itself, and the other being its use. The 'ease of use' refers to the later. Developing the test environment is certainly
a complex task. Once developed, it is understood, that using it is not only easy, but also it does not require the
test writer to have detailed knowledge of the test environment, the DUT or even the protocols the DUT uses.

To fully appreciate the need of UVM/OVM type of methodology,
it is recommended that the reader gets familiar with the AHB protocol specification.
A copy of AHB protocol spec can be found Here.
This tutorial uses AHB as an example Interface to explain how  to develop a UVM compliant test bench.



What we have learnt so far?
UVM/OVM is just a collection of 'rules', which define a standard way of coding a complex testbench!

Ah! one more thingi: Use UVM/OVM only for complex verification testbenches.
Write a UVM/OVM testbench for a counter, and you will immediately try to hunt down the UVM/OVM inventor for sure :).

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