A Verilog module is a building block that defines a design or testbench component, by defining the building block’s ports and internal behaviour. Higher-level modules can embed lower-level modules to create hierarchical designs. Different Verilog modules communicate with each other through Verilog port. Together, the many Verilog modules communicate and model dataflow of a larger, … Read more
Verilog always block is a procedural statement that starts an activity flow. It is essentially an infinite loop. However, when combined with a Verilog event expression, it can be used to model combinational and sequential logic.
Verilog generate statement is a powerful construct for writing configurable, synthesizable RTL. It can be used to create multiple instantiations of modules and code, or conditionally instantiate blocks of code. However, many Verilog programmers often have questions about how to use Verilog generate effectively. In this article, I will review the usage of three forms … Read more
SystemVerilog struct (ure) and union are very similar to their C programming counterparts, so you may already have a good idea of how they work. But have you tried using them in your RTL design? When used effectively, they can simplify your code and save a lot of typing. Recently, I tried incorporating SystemVerilog struct … Read more
In Clock Domain Crossing (CDC) Design – Part 2, I discussed potential problems with passing multiple signals across a clock domain, and one effective and safe way to do so. That circuit, however, does hot handle the case when the destination side logic cannot accept data and needs to back-pressure the source side. The two … Read more
In Clock Domain Crossing (CDC) Techniques – Part 1, I briefly discussed metastability and two methods to safely synchronize a single bit. While those techniques are commonly used, in many applications we need to synchronize multiple control or data bits, like an encoded state or a data bus. Synchronizing multiple bits brings a host of … Read more
Thank you for all your interest in my last post on Dual-Clock Asynchronous FIFO in SystemVerilog! I decided to continue the theme of clock domain crossing (CDC) design techniques, and look at several other methods for passing control signals and data between asynchronous clock domains. This is perfect timing because I’m just about to create … Read more
Apology for the lack of updates, but I have been on a rather long vacation to Asia and am slowly getting back into the rhythm of work and blogging. One of my first tasks after returning to work was to check over the RTL of an asynchronous FIFO in Verilog. What better way to relearn … Read more