I’m from Norway, but I live in Bangkok, Thailand. Before I started VHDLwhiz, I worked as an FPGA engineer in the defense industry. I earned my master’s degree in informatics at the University of Oslo.
Similar Posts
What is VHDL?
In short, VHDL is a computer language used for designing digital circuits. I use the term “computer language” to distinguish VHDL from other, more common programming languages like Java or C++. But is VHDL a programming language? Yes, it is. It’s a programming language that is of no use when it comes to creating computer…
Interactive testbench using Tcl
An interactive testbench is a simulator setup where input to the device under test (DUT) is provided by an operator while the testbench is running. Most often, this would mean you entering commands in the simulator console to provide the DUT with stimulus. While you should always create a self-checking testbench, an interactive testbench can…
Should I learn VHDL if Verilog is becoming more popular?
Which HDL is the most popular, and should I learn VHDL or Verilog? That’s a question I often get asked, and it’s understandable. People want to future-proof their learning by betting on the winning horse. But which one is it, and does it matter?
How to make an AXI FIFO in block RAM using the ready/valid handshake
I was a little annoyed by the peculiarities of the AXI interface the first time I had to create logic to interface an AXI module. Instead of the regular busy/valid, full/valid, or empty/valid control signals, the AXI interface uses two control signals named “ready” and “valid”. My frustration soon changed to awe. The AXI interface…
Formal verification in VHDL using PSL
When designing VHDL for safety-critical FPGA applications, it’s not enough to write testbenches at best-effort. You have to present proof that the module works as intended and without undesirable side-effects. Formal verification techniques can help you map a requirement to a test, proving that your VHDL module conforms to the specification. It’s an instrumental tool…
How to create your first VHDL program: Hello World!
When learning a new programming language, I always like to start by learning how to print. When you master outputting “Hello World!”, you know that you’ve got the environment working. It also shows you the basic skeleton of the language, the bare minimum code required to produce any output. You might be thinking: but VHDL…
First of all, thank you so very much!
These are by far the most comprehensible tutorials I have come across like ever!
Brilliant work.
So here my two cents out of gratitude:
Basic VHDL Quiz – part 4
Which statement is not true?
Answer 3 : The return statement cannot be omitted.
-> Correct
So the return statement CAN be omitted???
“Unlike in most other programming languages, the return keyword is mandatory in functions in VHDL.”
Confused by double negation. Me or you 😉
Good catch! I’ve changed the answer now. I was trying to make you think, but in the process I confused myself too 🙂
“The return-keyword cannot be used in a procedure”. I believe that this is incorrect, e.g.
https://web.archive.org/web/20200629023040/http://vhdl.renerta.com:80/source/vhd00060.htm
It is true, of course, that you cannot return a value with it, that’s the only (?) difference between procedures and functions. But, as in other languages, you can use “return” as control flow statement to “force an exit”.
You are right! I missed the possibility of using return statements in procedures without returning a value. According to the Renata link you posted, functions must return a value, while procedures can have return statements, but then without a return value.
I am changing this question.