Cocotb verification in python can turbo-charge chip development!

Cocotb, a new tool to test and verify chip designs, has been in the news.

Cocotb is a COroutine-based COsimulation TestBench environment for verifying VHDL and SystemVerilog RTL using python. Using open source, it will allow HDL code to bind with python code using VPI or VHPI implementation of the simulator.

We can get full access to DUT VHDL ports, and internal signals from python. For those unaware, a hardware description language (HDL) is used to describe structure and behavior of electronic circuits, to design ASICs and program FPGAs.

Verification ensures that implementation fulfils technical requirements and specifications. HDL testbenches script stimulus and verify outputs. They make use of software-like language features, which are not synthesizable. HDLs have been extended with features to support verification. They are still not as powerful and flexible as general-purpose programming languages.

Pradeep Salla manages the Verification team at SiemensEDA India. He said that when the SystemVerilog-based methodologies like OVM, and then UVM came up, these were adopted very quickly in India. You will find a lot of UVM experts in India. Now, some companies are seeing if they can incorporate python to write high-level tests. Hence, there is some exploration of Cocotb, which enables a python interface to UVM.

Europeans were using VHDL testbenches, and were reluctant to adopt SystemVerilog-based methodology, as there was a rampup that was needed by the engineers. As much as possible. they stuck to the traditional directed testbenches. Newer extensions, such as Cocotb and Open Source VHDL Verification Methodology (OSVVM) came up to reduce the rampup to newer methodologies from VHDL, and a path to advanced verification methodologies.

Philipp Wagner, Director, The FOSSi Foundation, stated that if you are migrating to Cocotb 2.0, first, upgrade to the latest Cocotb 1.x. Then, upgrade to Cocotb 2.0 (or current master version). You need to fix all the remaining issues. Verification is software! Cocotb 2.0 is around the corner. Cocotb is not just verification in python. It can turbo-charge chip development.