Converting VHDL to Verilog

Today I’d like to share a VHDL and Verilog tool.

Many novices have encountered a problem when learning FPGA for the first time: learning Verilog or VHDL?

Many beginners finally choose Verilog because:

VHDL is more rigorous and difficult to learn; Verilog is relatively free and easy to master quickly;

There are more and more Verilog and less VHDL. I feel that this is definitely a trend. Many IC design companies in China, Verilog has become the mainstream design language.

Verilog code runs fast and simulation performance is good, so netlist uses Verilog and VHDL package, but it is hard to write.

Most IP vendors use Verilog HDL for IP cores, and there are many mature Verilog designs available.

However, the current situation is as follows:

Not all the designs that can be found use Verilog. There are always some codes and IP cores many years ago designed in VHDL, but they are still in use.

Now many FPGA design software and simulation software support hybrid design, that is to say, some modules in your design can use Verilog design, and some modules can use VHDL design

As like as two peas, VHDL and Verilog are very fixed and simple. For those who have experience in programming, they will not be entangled in Verilog and VHDL. The two languages are completely interlinked. If they are a superficial reform, they are exactly the same. So Verilog and VHDL syntax can certainly be converted to each other.

But if you only know Verilog, but you get the design of VHDL, don’t worry. Now I will teach you how to convert Verilog and VHDL to each other.

Take the following VHDL code as an example and convert it to Verilog,

Converting VHDL to Verilog

We use the following widget to convert VHDL to Verilog

Converting VHDL to Verilog

Step 1: select the conversion mode, which can be VHDL – > “Verilog”, or Verilog to VHDL

Step 2: select the VHDL file to be converted and the path to generate Verilog file after conversion

Step 3: click the switch button to switch in a few seconds.

Here is the effect of the conversion:

Converting VHDL to Verilog

The converted format is not very beautiful, looking very comfortable! Even the complex state machine can be transformed clearly!

Which is better, VHDL or Verilog

These two languages are both hardware description languages for digital electronic system design. First of all, it should be clear that VHDL and Verilog are not developed for hardware design, but are currently used by us to design hardware. HDL is the abbreviation of hardware description language, and its Chinese name is “hardware description language”. In other words, HDL is not “hardware design language”. It is this word that determines that the vast majority of circuit designs must follow the RTL pattern to write code, rather than write HDL code that only conforms to syntax at will. Both languages are already IEEE standards. Which is better than VHDL vs Verilog?

common ground:

Now let’s take a look at what the two have in common:

1. It can represent the behavior and structure of circuit formally and abstractly;

2. Support the description of level and scope in logic design;

3. It can use high-level language to simplify the circuit behavior and structure, and has circuit simulation and verification mechanism to ensure the correctness of the design;

4. Support the comprehensive conversion of circuit description from high level to low level;

5. Hardware description has nothing to do with implementation process;

6. It is convenient for document management;

7. Easy to understand and design reuse


Each has its own characteristics. Verilog HDL has been launched for 20 years. It has a wide range of design groups and more mature resources than VHDL. A bigger advantage of Verilog is that it is very easy to master. It is a C-like language. As long as you have the programming foundation of C language, you can master this design technology in a relatively short time. The VHDL design is relatively difficult, which is similar to Ada language. This is because VHDL is not very intuitive and needs Ada Programming Foundation. It is generally believed that more than half a year’s professional training is required to master it.

The current version of Verilog HDL and VHDL differ in the coverage of behavioral level abstract modeling. It is generally believed that Verilog is slightly worse than VHDL in system level abstraction, but much better in gate level switch circuit description.

Verilog code runs fast and performs well in simulation, so Verilog is used in netlist. VHDL language is more rigorous, some grammatical errors can be found in the parsing stage, while Verilog and C are more free in similar language styles. Verilog is suitable for algorithm level, RTL level, logic level and gate level, while VHDL is suitable for super large system level design. Verilog is more flexible and efficient. Can achieve the same function with less code. And it has system functions that VHDL doesn’t have. VHDL is slightly higher in abstraction than Verilog, and has some functions that Verilog does not have, such as defining module ports as multi-dimensional array types, not specifying the specific encoding mode of state machine, etc.


What kind of hardware description language is used in digital logic design? At present, in the field of high-level digital system design in the United States, the application rate of Verilog and VHDL is 80% and 20%; Japan, Taiwan and the United States are almost the same; while in Europe, VHDL develops better. Many IC design companies in China adopt Verilog.

VHDL was developed by the U.S. military organization and became the standard in 1987, while Verilog became the standard only in 1995. Verilog was converted from the private property of a company. Why does Verilog become an IEEE standard?

I think it must have its unique advantages, Verilog has stronger vitality. Moreover, it is easy to get started, and many IC manufacturers accept Verilog HDL code as back-end chips. If we focus on the design of integrated circuits, we suggest learning Verilog HDL. VHDL emphasizes the synthesis of combinational logic, which is widely used in Colleges and universities.

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