FYI fpgas are not ‘programmed’. VHDL, Verilog, etc. are Hardware Design Languages, not programming languages. Its a whole different paradigm for design, is not just a program

@Adrian
A7 is correct. They refer to a “Programming File” in a sense that you are transferring a configuration file, not that you have written a program. The use of the word programming refers solely to the actual act of transferring the file from a PC to the physical FPGA or external flash, etc.

Also, the Nexys2 is not an FPGA, but a development board for the Xilinx Spartan 3E series of FPGAs. You can get the board with different versions of the FPGA.

So what is firmware but not a program that configures hardware through flashing it into the hardware’s memory( or in this case, circuit pathways)?

@A7 so you are saying Field Programmable Gate Arrays are not programmed?

@Charlie
If you’re just looking for fractal art, there’s always XaoS:
http://wmi.math.u-szeged.hu/xaos/doku.php

correction: “There ARE no instructions..”

@A7

“the fact that HDLs and programming languages look alike, cause this confusion on what is ‘program’ and what is not.”

I think the confusion is all yours. The article has nothing to do with the difference between “programs and designs”, it just happens to have a (extremely minor) error in terminology in the description. You were asinine and pedantic in pointing it out (and then ‘schooling’ us on the difference), and I followed suit by being asinine and pedantic towards your comment. Only charlie, Aaediwen, zeno, and noah have really added anything related to the article.

Thats kind of sad, no? Perhaps I should calm down. But it gets pretty tiring that almost every article on hackaday is picked apart for tiny errors in editing and the experts (not hacking experts, but rather editing experts) come out of the woodwork to give their two cents. On this article, I was part of the problem, but only so I could say – STOP IT. Stop with the crap editing comments. Stop turning this place into editoraday, no one wants to read it.

When doing VHDL etc. you are most definitely programming in the sense that you are defining a scheme of instructions for how the hardware should react to different input. The code is compiled and transferred to the FPGA (probably in the form of another type of program). Whether or not the stuff that the FPGA is running is code, when you are defining it you are programming.

Hi! Thanks for the interest in my project.

FPGAs are “programmable hardware”, the FPGA chip used used is roughly equivalent to half a million basic logic gates, with a few goodies like small RAM blocks and hardware multipliers. At hadrware reset reset the FPGA more-or-less ‘wires’ these gates based on a configuration held in flash.

With a flash update you can change the FPGA from maybe acting like a AVR compatible processor, to a 200MHz logic analyser, and then maybe an old school PDP or Cray computer.

It’s not simulated nor emulated, it’s actual digital logic doing what digital logic does. For example in my project I had to build the VGA display – controlling the hsync/vsync signals and when the colour bytes get squirted up the cable, and also build a memory controller to access the page-mode RAM chip (e.g. set address wait 80ns, read the byte and change low order bit, wait 20ns, read next byte…)

VHDL is very much like bit-banging I/O but worse. You need to know what is going on every cycle, and how long things need to take, and all you have to work with is the present system state and where you want to be ready for the flip-flops latching at the start of the next clock cycle. It changes your appreciation for how things really work!

And yes, there is an FPGA equivalent of assembler. Rather than using high level components like counters and registers you can use the basic logic blocks (mostly 16 bit look-up tables and flipflops) and choose where they are and how they are wired. Very tedious, but can be much faster and more efficient than using high level constructs!

Mike