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Arduino-Compatible FPGA Shield

Spartan 6 FPGA Shield includes SPI Configuration Flash, Breakout Headers, SRAM, programmable from Arduino or SPI Programmer

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This project was created on 01/21/2014 and last updated 23 days ago.

Description

Motivated by an interest in teaching folks how to use FPGAs and espouse the virtues of FPGA-coolness (& like many, frustrated a bit by a number of limitations of the Arduino incl. IO, peripherals, etc) I’ve endeavored to create the first (that I know of) FPGA-based Arduino shield.


This board - which I'm documenting here as I go along - includes heaps of additional IO, memory resources, etc. and is SPI programmable via SPI flash (including programming from the Arduino Due)...And is just an all-round cool way to introduce programmable device technology (beyond simple logic) to the uninitiated.

Likewise, it will have more than enough grunt for the old-pro to hack together some totally awesome, totally re-configurable systems.  

Details

Intending to keep this as compact as possible I'm looking at BGA packages for SRAM and std package for the SPI Flash.  The several that I've chosen will enable me to keep costs below $30 for the whole board (target = $25) and still have head room to do some really impressive stuff with it.  Likewise, this makes a sizeable "prototype area" available to fill with either additional connectors or PTH pads.

Programming of the SPI flash from Arduino is done via the ICSP header which carries thru to the "daughter" card.  Likewise, I've included a second chipselect (GPIO) to enable the ICSP to connect to the FPGA via SPI (were you to use an SPI slave core in the FPGA to drive FPGA functions...more on this in my next project ;)

Flash is meant to be large enough to be used by an FPGA processor in case someone wanted to use one, and also hold multiple images of the FPGA configuration if someone intends to make this harder to "brick".

Power is still undefined but relatively trivial.  Power supply will offer a few different rails and LEDs and line drivers will be used to provide some visual feedback of programming state and activity.

Git project -- https://github.com/sfgit/FPGA_Arduino_Shield.git

Components
  • 1 × XC6SLX9-2TQG144C Xilinx Spartan 6 LX9 FPGA - Device Playground
  • 1 × S25FL216K0PMFI041 Spansion 16K flash - to hold FPGA configuration
  • 1 × SN74CBTLV3257DBQR SPI Multiplexer - manages access to flash from multiple SPI sources
  • 1 × KC5032A20.0000CM0E00 Kyocera 20MHz CMOS Oscillator - FPGA clock source
  • 1 × IS61WV12816DBLL-10BLI ISSI SRAM - 128Kx16 Asynchronous

Project logs
  • Level Translation Mods

    23 days ago • 0 comments

    The first pass of this board was built with the Due in mind (3V3) and other development boards that I had sitting around, almost all of which *other* than Arduino were 3.3V.   In planning the evolution of this however, it quickly made sense to include support for other 5V devices such as the Uno and other Arduino boards.  So I have gone ahead and added a Level Translation circuit and respun the board now with some level translators that will convert the Arduino's 5V0 outputs to a nice, user-friendly 3V3 signal for the FPGA.  This'll ensure support for the Uno and other Arduino's not using 3V3 IO voltages.  Likewise, I made a few other small improvements and fixed a few snags that deserved some attention.  

    Testing the level translator on a breadboard...

    Schematic for the level translation circuit...

    Above is the schematic (new files will be uploaded to github shortly) for the level translator and because the layout needed to change pretty substantially to accommodate these two new devices, the boards went back to fab and are going thru proper assembly at the moment.  

    The part used for level translation is the SN74CBTD3384.  It's a 24-pin TSSOP and it's relatively small, cheap, and performs pretty well with very low series resistance.  Designed for performance up to about 10 MHz and provides  a nice interface to the arduino UNO and other 5V0 devices.  

  • Glamour shots

    2 months ago • 1 comment

    Nothing really to add here except a few simple glamour shots to show how things ended up.  Connected, in this case, to a Due just for fun.  

  • building a (budget) box I'd be happy to open

    2 months ago • 0 comments

    Recently I'd gotten a fair bit of interest from folks wanting to buy or or trade for one of these FPGA boards...And I must admit, I'm not terribly capitalistic when it comes to stuff I build outside of the work context (I often find I just end up giving stuff away, rather than trying to profit on them).  Still, I feel that generally everything I build is a reflection / measure of me and my interests and passions and enthusiasm and as a result, I hate to "ship" junk.  And I hate to own junk!  Better put: I want things to look pro, even if they're outside of the professional context (things move slower, but they just tend to be more 'agreeable' all-round).   

    So when it came time to come up with boxes to ship to folks, I thought I'd spend a little time trying to get this right.  And though I began by getting it wrong - all wrong - I managed to recover nicely I think and these express the 'spirit' of this board in a way that makes me comfortable sending it to my mates / others I've come to know thru electronics / n'er-do-well hackers, what-not.

    So the first order of boxes arrived an candidly, they sucked.  Corrugated die cut, white on one side, natural on the other.  The white is faded, poorly applied, the folds are not crisp and clean, the slots look to have been cut far to large for the flap thickness (makes the boxes loose along the edges) and the overall accuracy is rubbish.  I'm embarrassed for the USA stamp they bothered to apply to a crap box.   You can see the thin paper over the corrugation making them weak and hard to managed without some serious tape / glue.  Have a look:

    *****

    **Still, I tried to "make-do" (if I find myself using this expression, it is undoubtedly a reflection of frustration and poor judgement more than anything else)

    ***

    ***Ok, complete rubbish.  I will NOT send this off to a friend.  It's totally unacceptable (I'm that guy that puts stickers in a box along with your xmas present...details!).  So I packed it in and I pinged my good friends at Uline.  They are pro.  They do boxes.  All sorts of boxes.  And they do them well.  

    What I got was a far superior product.  Well cut, sturdy,  and although slightly larger (4x4" vs 3x3") there is clearly a far better process afoot here than at the first place I used.  Still die cut but looks to been done with better materials, better equipment, and the sort of love I like to see. Have a look:

    ***

    ***Now that I had a better box, I still didn't have an awesome one.  I had something nice, solid, more precise, but I wanted awesomeness.  Maybe not apple's barely-air-gets-through precision (impossible to do in my house on a budget) but something that at least looked cool and that I might keep after I took the board out and use for knickknacks like jumpers or those extra header bits or such.  Nice to pack away that arduino or flying leads and have some room for the USB cable and what-not.  

    So I go my thinking cap on and thought to use the Hackaday logo on the outside of the box.

    First I tried some die-cut stickers...

    ***

    ***

    Nah, fail.  Nice and all, but too much contrast, not enough of a story in there.  

    This is a board for people who want to build whacky shit with FPGAs and it should reflect that.  I couldn't have a clean edge, precision cut sticker on the box.  (Inside maybe)  I needed something that also complemented the rough edges of the imperfect box.  So I just happened to be sitting in my office and inspired by a pic of graffiti that serves as my desktop background, I decided to use spraypaint.  

    (Think: sweet road crew awesomness...what better to have in your gearbag than an FPGA board?)  

    ...But with what image?  Why the Hackaday logo of course!  (thank you to the die cut sticker that served as my cheap stencil)

    ***

    Tag that thing...

    ***

    ***

    ***The lineup...

    ***

    ***Something I'd keep on my desk......

    Read more »

View all 32 project logs

Build instructions
  • 1

    Step 6 - Wire up JTAG connections for JTAG programming.

  • 2

    Step 1 - Don't panic.

  • 3

    Step 3 - Build major footprints:  Costing the available board area requires building the major footprints and placing them on the PCB.  Built early footprints and placed to determine what additional space is avail.  Files in git.

See all instructions

Discussions

zakhounet wrote 22 days ago null point

How could I get one ??

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Chris Arena wrote a month ago null point

Great project!! How can I get one?

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Xark wrote a month ago null point

I am a bit bummed that I got my new FPGA board and I can't use it because it is using some wacky non "Arduino standard" barrel connector for power. A few guesses at barrel connectors for a power adapter at Radio Shack failed too. Take note if you order one of these (as well as 3.3v only, so pretty much "Due" Arduino only).

Other than that, looked like a pretty nice board...

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mattberggren wrote a month ago null point

Thanks for the feedback mate. Heads up, if you prefer the 5V version, let me know. I have them being tested atm and they should be ready in a week. I'd be happy to swap it out if you prefer one for the Uno, etc. I chose the 3V3 version as most of the dev boards I have hanging around are 3V3 and most FPGAs have long moved past 5V0 for anything. Actually the only thing I have that is 5V0 was Arduino but I tend toward using Due. :)

Still, I can appreciate it could be frustrating so just let me know and I'll swap it out (you can rock that one until these are fully tested). Want you to be happy with what you got! I've put a lot of thought into this so I want you to have a great experience. My email is just my username at gmail.com.

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Xark wrote a month ago null point

Thanks for your reply.

I am actually mostly fine with 3.3v as I have a Due. However, it could have been a bit more clear on the product page (I didn't not even know it was 3.3v only until I read the note that came with the board).

The non-standard power connector is much more annoying (and AFAIK not mentioned anywhere - I spent five minutes trying to find the type on this project page and github using my phone at Radio Shack). I am quite puzzled about why you decided to use the "odd" connector making an "Arduino compatible" FPGA? Please consider changing this in future revisions. I probably have over a dozen development boards and all use either USB or "normal" barrel connector (albeit some at 5v not ~9v).

I'll have to go back to Radio Shack with board in hand and keep trying power adapter connectors (each sold separately) for my universal adapter until I find the right one (my earlier two "eye-balled" guesses were incorrect at ~$5 a pop - who knew there were so many barrel connector "flavors").

It also would be helpful if there was a page about what all the jumpers and connectors do and FPGA pinouts etc. (and maybe include a few jumpers...I had to salvage an old PC for some). The silk screen is difficult to read (and a tad cryptic). I think I figured everything out from studying the schematic (but I probably shouldn't have to).

Sorry if I came off grumpy and unhappy, but I was indeed a bit bummed to get home and not be able to (easily) play with my cool new FPGA board. Thanks for your offer to try to make me happy. Mostly I think I needed more and better information about your board presented on the product page ("tech specs" seems to be missing some critical info) :-)

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Xark wrote a month ago null point

I just wanted to mention that I finally had time to find a suitable power connector (as I suspected, same outer dimensions as Arduino barrel connector, but with insidiously wider inner + pin).

Once the board was powered, I had no trouble hooking up JTAG and managed to get my LED blinky to work on the first try (after studying the schematics to get the constraints file right).

Am am still puzzled by how to program the FPGA SPI config flash with Impact (perhaps you can't - it doesn't seem to list the Spansion part number used). Any info you have on this would be helpful.

So, overall a happy customer. :-)

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Christoph wrote 2 months ago null point

So is this ready for trying myself or do you still need to do some work on the boards? What would it take to assemble one?

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technolomaniac wrote 2 months ago null point

Sorry for the delayed reply! So the board is ready. This first iteration is 3V3 tolerant and there is a second type that uses level translators to support the Arudino UNO voltages. So the long and the short is: if you want to use with Arduino, just be sure it's one of the 3V3 versions of the Arduino (i.e. Due). I chose to do the 3V3 version first because most of my other dev HW is 3V3 and *not* 5V0 like the Uno.

That being said, this is totally ready for the road. I have a few on my desktop and they are all working brilliantly. The thing that can be a sticking point in assembling these is the BGA and the QFM but I promise, with a decent stencil, you're good to go, and if you can nag a friend with a laser cutter to make a solder paste stencil for you, you should be able to build them yourself no probs. This is a process I would strongly encourage anyone with a little bit of patience to go thru as it's super useful.

With a stencil, just use hot air. You don't need a hot plate or reflow or such. You can of course use it, but it's not a hard fast req. I use hot air most of the time and it works a treat.

Sadly, I did notice stock on the LM1086 is super low. That said, I bought 1000. If you need some, let me know and I'll ship you some at cost + shipping. TI is lagging on making more and it forced me to buy a bunch to get things moving on my end. Now I have inventory! :)

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dan wrote 2 months ago null point

Hi! Sorry for a bit stupid question, but can you tell me is it possible to use FPGA as a lines swithcher/connector for electronic components? What I mean - I thinking on implementation more convenient breadboard for prototypes. This mean, that it has pinholes but all connectors hided inside it and switched automatically. Each pin can be connected to each another pin. You can attach to this board all needed electronic component one by one in any order and than "just" set switches to make needed connections. I was thinking a lot on mechanical implementation, but may be FPGA solution also may serve well enough for this purpouse?

Can you please tell me - is it possible to use FPGA as completely "transparent" (without any modifications of incoming signal) programmable electrical switcher so it can connect different pins in any order? And if it's possible what max electrical parameters of these signals?

Thanks a lot.

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technolomaniac wrote 2 months ago null point

Yes. You can completely do what you are asking. There are a few small things I would say could get in the way and that is mostly around voltage levels, but I otherwise, I use FPGAs as a virtual breadboard all the time. It's just easy to control the IO and they can always be reused for something else later on. This is largely why I love having a board on my desktop as once stuff is wired up, I can make things input, output, bidirectional, and swap this on a whim. It's much cleaner than having a mess of wires to move around. What's more, when something is wrong, it's easy to switch pins internally (simple port swap).

If you have more detail on the application I can help you out. My email is just my username @ gmail.com.

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Eric Han wrote 3 months ago null point

Hello there. This is Eric from ISSI. Please email me at ehan@issi.com if you need any help with design, etc. We also provide mixed signal, led, audio amplifiers, serial flash, as well as a broad range of high performance SRAM/DRAMs. Great work on this, it's truly inspirational to see one person come up with something like this. I am currently working on integrating our newly aquired SPI Flash department. Let me know if you need any help! = )

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technolomaniac wrote 2 months ago null point

Love you memories guys! I would love to hear more about the SPI flash line. I have always used spansion because they were a) cheaper than xilinx platform flash ($$$) and the b) the documentation for using them with Xilinx devices is awesome. If you want to discuss, I'm happy to chat. My email is just my username @gmail.com.

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Mark Dean wrote 4 months ago null point

I am interested in purchasing a couple of boards. Are they available for purchase? Do you also have a BOM and a source for the parts (a single source would be convenient.) Finally, I think this would be a good board to use in university level class projects (EE/CS majors, junior/senior/graduate level). How long would it take to fill a larger order (e.g. 25-50)? Thanks...Great project.

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technolomaniac wrote 2 months ago null point

They are just coming online for sale! Should be avail in a few days. I can spin up inventory quickly if required. I have 50 or so on hand and more on the way. The first batch is 3V3 tolerant and the next is 5V0 for use with the Arduino Uno. Happy to chat in more detail, my email is just my username @gmail.com.

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i.abdalkader wrote 4 months ago null point

Nice work, post pics of the board when it's ready :) btw, if you need more ram, there's a $5 64Mb PSRAM from ISSI (IS66WVE4M16BLL)

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technolomaniac wrote 4 months ago null point

Thanks! This was actually a reason to pick the BGA I did was that there are so many drop-in replacements for this. You'll see in the schematics that I also brought out extra pads for mem that aren't used by this device. I did that so where additional memory resources are required, the ADDR lines would be available to those folks dropping in a new SRAM. Just need to remember to tent the bloody vias! Rev B has tented vias on the BGA pads. :| Makes hot-air soldering much, much easier.

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tobias.kornmayer wrote 5 months ago null point

Cool project! You may want to have a look at Papilio Due, which is currently on Kickstarter. What I like about your design is the lower cost, even if you used less RAM.

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technolomaniac wrote 4 months ago null point

Thanks! I saw this and I like it quite a bit! I like that they've tried to simplify the design-entry piece as well. This is something we did when I was with Altium and something I'm working on with HDL netlisters for KiCAD and Eagle. I'll convert the Xilinx standard primitive libraries to libs in KiCAD and Eagle (in time) to make it easy to just "draw" logic using a decent schematic front end. Some complexities with configurable parts are hard to implement but this should be a nice, simplified entry point for people that are afraid of the Xilinx SW. Still, expect a few videos on how to use the Xilinx tools to come out here very soon! I'm a big believer that once the concepts are understood, this actually *isn't* that hard to get something working. It's more getting over that conceptual / workflow hurdle and build confidence like you do making your first few LEDs blink with arduino or what-not. And this is all fairly easily but not well explained. I'm going to put some energy into explaining this.

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surubarescu wrote 6 months ago null point

Marvelous project ! I've been waiting for long to see an affordable FPGA board, but this being an Arduino shield (but not only) it's fantastic.

I got some questions (as a complete newbie in FPGA domain):
Is it possible to use this or other FPGA to drive a 3D printer or a CNC - in respect with the computation power and speed?
Is it possible to reconfigure the FPGA (or parts of it) while it's running?
Is it possible to configure the FPGA other way than using the manufacturer's software?

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Jarrett wrote 5 months ago null point

The manufacturer software is free, but yes, many companies have software that can create the appropriate .bit file (Altera, Xilinx, even Altium and probably open source solutions, too)

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technolomaniac wrote 4 months ago null point

Hi there! The FPGA could be used to drive motors pretty easily and I've used them to drive a variety of them in the past. So this isn't a major headache. Regarding programming while the system is running, this isn't possible if you mean a wholesale reprogram of the FPGA while it's still running however you can create logic in the FPGA system that responds to events that can trigger complex changes in system behaviour. Things like crosspoint switches are a simple example of modifying the FPGA system in response to some event. I'll do some videos on these sorts of things now that the board is populated and everything is running like clockwork.

However to completely reprogram the FPGA, you'll need to trigger a reboot of the device. Programming the FPGA is like changing the motor on the car. Can't do it while the motor is running :). However, the rest of the system *can* continue to run. So think of it much like a micro. You can't do a complete reprogram of the CPU while it's running but you can create applications and logic that run on the FPGA fabric that *can* be modified in-system.

On your last question, you'll need the manufacturer tools to program the device *however* they are free for this device! This is one of the reasons I chose this part. The tools will be something I take everyone thru in the follow-on videos about to come out! (Sorry I've slacked in the video output!) I have also been playing with a cool KiCAD front-end that allows you to place logic in KiCAD schematic and generate a netlist that can be pushed to the mfg. tools. More on this soon! (This is largely the reason for the delays on the video side was trying to solve the design-entry "problem" for non-FPGA gurus...Should be doing something for Eagle relatively soon also).

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surubarescu wrote 4 months ago null point

technomaniac -> i was thinking of reprogramming parts of the FPGA like loading a library in software in overlay mode, i.e. you build an automatic pilot, and you'll need three different "programs" for take off, level flying and landing and you need only one of them at a time, but you cannot have all of them in the FPGA at the same time due to limited space, while some part of the FPGA stays in control.
I would like to have one board to learn more about FPGAs, how can i contact you directly to talk about that (i couldn't find a way to send you a direct message/email)?

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technolomaniac wrote 4 months ago null point

@Surubarescu -- heads up, my direct email is just my username @gmail.com. Trying to avoid the spam crawlers a bit. :) I have a new round of boards in the pipeline and coming back very soon. Once I have them, happy to ship you one at my cost. I think with shipping and parts and such, this is still well-under $50. Not sure where I'll take these yet but it seems from posts that Hackaday will launch a store soon. If that's the case, I'll definitely put these in there. Also, just wrapped up and am editing a video on how to use the Xilinx tools. Alongside that, I'm doing one on VHDL / Verilog basics (with a focus on the patterns that professionals use) and how to break up a design into combinatorial and sequential patterns that map easily to hardware. Should be released soon.

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Adam Vadala-Roth wrote 6 months ago null point

Finally this is finished, I'm eager to take cues from your schematic on a BGA256 Spartan 6 board I've been planning. +1 for Altium its my favorite tool!

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technolomaniac wrote 6 months ago null point

Thanks Adam! Just made some simple little tweaks today. Nothing earth shattering but things I knew were necessary but not req'd when testing prototypes. got stencils today so I can solder this up and do some testing of the current prototypes. :)

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phreaknik wrote 6 months ago null point

What PCB design software is this using? Great project BTW!

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phreaknik wrote 6 months ago null point

NVM, I see you are using Altium. You just have a newer version than me! :)

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technolomaniac wrote 6 months ago null point

Altium Designer versions 13 and 14.1. Been slow to do it, but I've been migrating the whole project to KiCad. Going to try and contribute a bit on that project. Seems pretty awesome and I've got some background in that space (building tools).

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hackhead79 wrote 7 months ago null point

I am still in the beginning stages of being a maker (just made my dive into the Arduino world with an Arduino Mega 2560 ) but reading about FPGAs seriously tickles my maker bone. I would love to learn how to use FPGAs (including learning VHDL). Especially after buying a 5" display for my Pi for about 5€ and realising it needs an FPGA/CPLD controller to work.
So by the time your board is ready, I would be very glad to use your board as my first FPGA/VHDL -learning platform!

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technolomaniac wrote 7 months ago null point

Awesome to hear. And I'm preparing a series of videos on FPGA basics. The concepts, like anything, take a little effort, but after you nail the basics it's relatively straight-forward. I'll have some boards for cost once this is all said and done (design is actually further than what I've documented so far) so if you'd like one, drop me a line and I can give you a BOM cost and assembly and such and share a "kit" or a completed board. The only real beasts to solder are the super small QFN packages. With solder paste and an oven or hot air, it's all within reach.

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hackhead79 wrote 7 months ago null point

That sounds awesome! Yeah, it would be cool if you could send me the BOM for a kit or similar!
I read a 65-page VHDL primer a few days ago of which I understood a pretty good deal (I have some light to moderate previous programming experience) and it really seems manageable, very logical and much clearer than C[++] and the likes. I really like that processes can be timed very accurately and that multiple processes can run in a truly parallel fashion.

From what I've seen on Youtube, small pitch SMD soldering does not look like rocket science but I might be wrong ;). I'll try my hand a these small footprints in a few days on a DIY CPLD board when the components arrive. (I'll start a project here on hackaday projects about it in a few minutes - the board is built with a Xilinx XC9536XL but has only about a tenth the amount of logic units your board will bring, i.e. 800 logic gates, 36 Macrocells compared to 9152 the Spartan 6 XL9 has!).

Sooner or later I want to upgrade to FPGA anyhow, so it would be really cool to assemble and bring to use one of your FPGA boards so BOM / cost for a kit or similar sounds great. And I am looking forward to your video series to learn more about FPGA programming!

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mkr506 wrote 8 months ago null point

Thanks, this .. is.. Great! i'm a second year student at uni (york UK ... Woo!) and this is a perfect project since its holiday time, i've now been introduced to vhdl (and the joy that is Xilinx software) -and i'm also totally skint!!! Thanks for all the future stuff

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technolomaniac wrote 8 months ago null point

Awesome! I'll keep posting updates however if you're keen to test a prototype, pm me on twitter @technolomaniac and after I spin them up, I'd be happy to try and ship you one.

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DubStation Freeside wrote 8 months ago null point

KUDOS. This could be a really awesome thing. I know we'll be playing with them asap.
Considering the fact that stuxnet is still probably floating around, I predict much dark humor surrounding said shields.

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technolomaniac wrote 8 months ago null point

Ha! Indeed. This certainly has "dark potential". Was thinking it'd make a fun way to introduce people to bitcoin mining as well. There's heaps of those cores out there and they are a good lesson in the virtues of FPGAs and how their resources differ from an OTS CPU.

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Eric Evenchick wrote 8 months ago null point

Seems like a great, cheap way to get into FPGAs and HDL. I can imagine a ton of ways to use the Arduino and available shields for communication, and use the FPGA for heavy lifting.

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technolomaniac wrote 9 months ago null point

Added some content to new git repo for this project. Nothing too fancy yet, just costing the board area versus component sizes. See here: https://github.com/sfgit/FPGA_Arduino_Shield/

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