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
How to generate random numbers in VHDL
VHDL has a built-in pseudo-random generator, but it can only generate floating-point numbers between 0 and 1. Fortunately, you can derive from this any other kind of random data format you should need. Continue reading this article to find out how to produce real or integer values of any range, as well as random std_logic_vector…
How to create a Tcl-driven testbench for a VHDL code lock module
Most VHDL simulators use the Tool Command Language (Tcl) as their scripting language. When you type a command in the console of the simulator, you are using Tcl. Furthermore, you can create scripts with Tcl that run in the simulator and interact with your VHDL code. In this article, we will create a self-checking testbench…
Basic VHDL quiz – Part 2
Test your coding skills with this VHDL quiz after completing tutorials 6-11 from the Basic VHDL Tutorial series!
How to install a VHDL simulator and editor for free
Although VHDL and FPGA tools are often very expensive, it is easy to access state-of-the-art software for free if you are a student. There are several simulators, editors, and IDEs for working with VHDL. This article shows you how to install two of the most popular programs used by VHDL engineers. VHDL simulator Siemens EDA’s…
How to use an impure function in VHDL
An impure function can read or write any signal within its scope, also those that are not on the parameter list. We say that the function has side effects. What we mean by “side effects” is that it is not guaranteed that the function will return the same value every time it is called with…
How to create a ring buffer FIFO in VHDL
Circular buffers are popular constructs for creating queues in sequential programming languages, but they can also be implemented in hardware. In this article, we will create a ring buffer in VHDL to implement a FIFO in block RAM. There are many design decisions you will have to make when implementing a FIFO. What kind of…
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.