One question that I’ve debated many times over the years is whether it’s OK to use variables for registers in VHDL. It’s safe to say that newbies are more likely to do it than experienced VHDL designers. But is there any merit to that, or is it just a matter of preference?
In this blog post, I will try to shed some light on the issue so that you can make an informed decision about using this design practice.
Many people turn to me for advice regarding their FPGA projects. Often, my answer is not what they expected: have you considered using a microcontroller instead of an FPGA?
I’m running VHDLwhiz, the website dedicated to FPGA design using VHDL. My life revolves around FPGAs, and I’m the biggest proponent of VHDL there is. Why would I say such a thing?
It’s because, for some tasks, an FPGA is overkill.
FPGA engineers are in high demand throughout the world’s defense industry. Military technology has extreme requirements for reliability and efficiency, things that can be provided by an FPGA.
As an FPGA developer, you will always be working for companies with particular needs, because FPGA development is expensive and difficult. The arms industry has both the need and the money, and therefore employs a lot of FPGA designers.
Based on my master’s thesis,
Tcl is the programming language that goes hand in hand with VHDL. You may choose to learn Verilog instead of VHDL, but you will be exposed to Tcl no matter which HDL you decide to use. That is because most FPGA related programs, such as simulators and synthesis tools, use Tcl in their command shells.
Having a standardized scripting language for software tools is actually very clever. It enables you to transfer your scripting skills from one tool to the next.
As most hardware engineers, I started off my computer science career by learning a sequential programming language. The first language I learned at the University of Oslo was Java. While it’s not considered to be the most exciting language today, at the time, Java was at the pinnacle of its popularity.
The engineers who built Java were trying to solve a number of issues which earlier languages were lacking in one blow. Perhaps a wise decision to do a fresh start instead of continuing down the C path and creating C+++.
