Simple FPGA recommendations... - Page 1
Forum section: electronics / general

author: alank2
author_rank: Super Contributor
timestamp: November 01, 2013, 03:25:18 pm
content: Hi Everyone,I'm very fascinated by the FPGA and what it can do. I've been working with AVR's and have a good handle on them, but that is mostly what I've done so far. Can anyone recommend a basic FPGA that is what someone starting out with FPGA's would get acquainted to easily. My first plan would be to download the datasheet(s) and see if I can understand them!Thanks,Alan

author: Kohanbash
author_rank: Regular Contributor
timestamp: November 01, 2013, 03:34:10 pm
content: Quote from: alank2 on November 01, 2013, 03:25:18 pmHiI am not going to recommend a specific board (there are many other recommendations in this blog site. But once you choose an FPGA manufacturer you can start playing with the development tools and learning the basics.Don't get disheartened if you dont understand the datasheets. There is a lot of stuff in them and there are thousands of pages of documentation for each FPGA.Cheers!

author: nctnico
author_rank: Super Contributor
timestamp: November 01, 2013, 04:11:35 pm
content: I'd start with CPLDs. These are simpler, need only 1 supply voltage and are available in PLCC and QFP packages. Personally I like Xilinx' XC9500 series for small projects. If I need memory in a project I simply attach an SRAM to the CPLD.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 01, 2013, 04:33:05 pm
content: Quote from: nctnico on November 01, 2013, 04:11:35 pmI'd disagree - simple device means more effort to get it to do what you want once you start adding functionality. Once you get to devices with more than 64/72 macrocells, small FPGAs are often cheaper.With an FPGA it will just do it as there is plenty of space, as well as useful stuff like dual-port RAMs.I like the Lattice XO2. as it has onboard config memory, core voltage reg and (not very accurate) oscillator. Lattice do some vary cheap basic breakout boards with onboard programmers, so probably the cheapest entry route.Probably the only FPGA family that can do a LED blinky with nothing but power connected! Also a low pin count version (QFN32).One advantage of CPLDs is the compile time is a lot faster.

author: Dongulus
author_rank: Regular Contributor
timestamp: November 01, 2013, 05:09:02 pm
content: Before you get in to FPGAs, you should understand what's ahead for you. Designing with programmable logic is conceptually very different from microcontrollers. As such, there is a steep learning curve involved. To start, you might have seek out an overview of some basic hardware building blocks (NOT, AND, OR, XOR, flip-flops). When you design with programmable logic, you don't always have to be thinking about each individual logic gate that will be used, but there are many traps for those who don't have an understanding of the hardware underlying the design. This leads me to hardware description languages. You will need to look into either of two HDLs: Verilog or VHDL. Search the forums, there certainly already exists threads discussing the advantages and disadvantages of both. These languages picky and a bit awkward and don't work as you would expect if you are approaching it from say, C.I strongly suggest that you look at one of either the two big companies that have been in the programmable logic game for a while: Xilinx or Altera. I would recommend either theDE0 Dev Boardwhich uses the Altera Cyclone III 3C16 for theDigilent Nexys 2which uses the Xilinx Spartan-3. I haven't personally used Altera, but most everyone I hear swears by their development software, but again, you can probably find another thread that discusses the difference. Each of these dev boards have lots of peripherals already installed so you don't need to wire something on a breadboard. This is especially valuable for learning with FPGAs because you can invest more time into understanding design concepts rather than worrying about wiring components correctly (though both boards have expansion headers if you want to eventually use them. At first you will have to suffer through boring basic dummy circuits that involve toggling LEDs with switches, but soon you will step up to more advanced and interesting designs.

author: nctnico
author_rank: Super Contributor
timestamp: November 01, 2013, 05:51:31 pm
content: Quote from: mikeselectricstuff on November 01, 2013, 04:33:05 pmI wouldn't stare myself blind at the prices (the XC9500 devices are very cheap in single quantities BTW). Another big advantage of CPLDs is that the timing is predictable. This is much less so for FPGAs. Setting up proper timing constraints and/or finding out where a timing problem is located in an FPGA design isn't easy for a beginner. Anyway I started with CPLDs and from there the step to FPGAs wasn't so big especially if you can continue to use the same tools.

author: lorth
author_rank: Contributor
timestamp: November 01, 2013, 07:29:37 pm
content: Quote from: nctnico on November 01, 2013, 05:51:31 pmI don't thing a beginner is going to face timing problems...I would suggest Alteras DE0 and DE0-Nano... Simulation is a little bit harder in Altera than in Xilinx... From Xilinx, the Atlys boards from Digilent are great.BTW, are there any true CPLDs still? because many CPLDs from Altera/Xilinx are more like very small FPGAs than CPLDs...