cheap FPGA module - Page 1
Forum section: electronics / general

author: thinlayer
author_rank: Contributor
timestamp: June 28, 2013, 12:39:00 am
content: Here's a campaign on IndieGoGo for a cheap Cyclone IV FPGA Module. Has a dev board that uses Arduino shields for peripherals. Lots of free code avail.http://igg.me/at/fpga-module/x/3703559A good system? Worth supporting?Your thoughts...?

author: marshallh
author_rank: Unknown
timestamp: June 28, 2013, 12:54:55 am
content: Come on Brent, the least you could do is put a USB blaster on it.Let's be realistic, the guys like me that are using FPGAs use them in extremely niche markets. And we roll our own pcbs.The sad fact is that FPGAs are hardly a magic bullet, and thats what you are marketing this as.Someone that wanted to do things with FPGAs would be better served with a DE2-115, or even a DE0-nano.As you probably know, Sparkfun used to sell bare Cyclones. They barely sold any (and I bought the excess leftover).Also why is your fpga decoupling scattered around it on the top layer? It ain't doing diddly squat out there. It needs to be right under the dogbones on the bottom. Then you'd have to use a proper mezzanine connector instead of soldering it down the shield pcb.I wish you the best of luck but you are obviously pandering to the whoopee 3d printer/arduino type crowd. And they are going to be disappointed when it turns out that writing HDL is not like writing C as you advertised.

author: thinlayer
author_rank: Contributor
timestamp: June 28, 2013, 04:02:09 am
content: Ouch. Harsh. But thankyou for giving me the oportunity to cut you to shreds.1) I just spent a few years in FPGA distribution. I've been lucky to see a LOT of products and work with a lot of design teams. I can say the follow with confidence that: no one does a Cyclone board with components on both sides. Cheap chip + expensive assembly = not make sense much.Low cost means getting it done on a single sided assembly. I have seen plenty of Arria, Spartan 6 and even a Virtex-5 layout that are single sided in real manufacture, in real volume. You've got to rememer that a via is a narrow, resistive, inductive path and decoupling on the bottom side is not a lot better than decoupling a top side plane. That's why vias get backdrilled on RF boards. A plane on the top side is actually a BETTER solution. Planes have very little inductance and form a better return path for currents, so are effective EMC shielding too. GND bounce occurs on traces, and vias, not planes. On an F256 package, you are also quite close to the ball - I would hesitate on a F780 package, but in fact I've seen it done there too.2) USB Blaster - When you go to build your own board, you need to have one. So why would I load up the dev board with $30 of parts and testing that you can't re-use, when you can spend $50 but keep re-using it? Didn't appeal; went with flexibility and keeping it simple. If you are planning on never going to a custom PCB then yes - it is a $50 adder, you have a valid point there, but I want people to migrate their designs to PCBs one day - and having a module makes that really quite simple - especially when most shields come with EagleCAD files you can drop down. 2 Layer boards are so freeken cheap now that this is the way electronics should move. Less wires everywhere and $hit falling off a dev board; more nice simple, robust $50 2 layer boards with modules on them. Less likely to crash your prototype UAV.What I'm thinking of doing is getting a USB-Blaster clone and bundling it with the boards. But I was waiting for feedback first. Thanks for the feedback.3) DE2-115... it's $595... are you kidding me? And the peripherals are totally fixed and won't suite everyone. At least my board lets you swap the peripherals around, and there are 300+ shields. I'm not joking - have a look at the shield database shieldlist.org. Even the academic price on DE2-115 is $295. If you buy my board for $175, + postage + usb_blaster you're only up to $265, so you have money left for a shield. My board has DDR2 vs DDR, four times as much, twice as much SRAM, and have you tried to do anything with Terasic's code?DE0_NANO is a better sell, but it's still $80 and it isn't a dev board. It's a module. If you compare it to our module: we are $20 cheaper minimum, has DDR2, more of it, more sram, an ATSHA204 crypto IC, more flash, and it's smaller with a more rugged finish. No fasteners. We're qualifying the module for pick and place use, and oven reflow too - so you have more options for low cost assmebly.4) Rolling your own PCB is great, that's what we WANT to see more of, but we're trying to save you having to roll a board with 3x BGAs on it. That's a real bitch to get right by hand. Instead roll your own 2 layer board, but then use our module on it for $40~$60. Compare that to buying discreet parts from Digikey. Concentrate on your peripherals and your application specific circuits this way.Copying a reference design is a great way to waste a couple of months.5) The problem with selling a bare cyclone FPGA is that it needs a system around it and that's hard work. It's not an MCU. The point of a module is to put that system around it, and standardise the hardware so you can standardise the support. Now everyone can use the same templates, drivers, example projects, etc.6) There are NO magic bullets, but we're at 28nm silicon now. 20nm is next year. It's driving cost down like crazy. These Cyclone IV FPGAs cost less now than a high end PIC (albeit not from Digikey). They're coming to general applications quickly, not just specialty niche work.No, HDL is not easy to write, but Verilog is based on C, and SystemVerilog takes away all those trivialities associated with reg and wire. There are incremental improvements in every new Quartus release, and you can just download a Nios2 template and get on with it if you want.I think that we're all going to have to be multi-lingual in the future. If you want to know a good languge to invest in - SystemVerilog is a great one with a big future. Stop living in a C bubble.So do you want a loaner for a few weeks? Send me your address and I'll post you one. support@thin-layer-embedded.com :-)

author: marshallh
author_rank: Unknown
timestamp: June 28, 2013, 05:34:55 am
content: With regards to cap placement on the top. What about SSN with fully utilized LEs in a dsp heavy design, not all on-die decoupling can save you there. The core voltage is going to be worst off since its supply is in the middle of the ballout. As you mentioned below geometries are constantly getting smaller. They also have tighter supply margins.Digilent Nexys boards are this way. They whacked all the bypass caps in quadrants away from the BGA, so they could break out the package on 4 layers. I know of at least one who's had erratic i/o and glitching because of this poor layout. However if you are confident you can get away with it, your call.The usb blaster clones vary a lot in their "quality" I'd guess you say. Some are based on the cypress FX2 and are several times slower than the "real" hardware. Others are based on 8051 usb mcus. The one I got did not work until I chopped the provided idc cable in half. Loading a SOF onto a EP4CE30 takes about 9 seconds with it. The real setup is a FT245 and MAX II. Probably less than $10 in volume. All the ebay units with mini-USB ports are FX2 based. Would you have your customer rely on a chinese POS creating a possible support headache? Your callYou have a good point about the bitch work involved in doing support circuitry for your typical fpga. And the solderable support module idea? I don't have any use for this kind of thing myself but I linked it to some other people that might.Everyone trumpets how FPGAs are finally "going mainstream", being preached to by Arrow reps that claim the cyclone 5 is going to be in egg timers.I'm interested to see what kind of SystemVerilog code you are talking about, and how much compromise is involved when you start working at a higher level. If you have some sample code feel free to PM or post. HDL mindset in general is the #1 thing (the vendor software being second) that I see newbies struggling over. Thanks for the loaner offer but I have scads of boards I dont' have the time to mess with as it is.

author: Stonent
author_rank: Super Contributor
timestamp: June 28, 2013, 05:46:16 am
content: If you buy one of those imitation Saleae Logic Analyzers on Ebay they can be reprogrammed to be a USB Blaster, about $9 or so.

author: nuhamind2
author_rank: Regular Contributor
timestamp: June 28, 2013, 02:51:45 pm
content: Chinese Saleae clone has it's input buffer set as input only,so it can't be used as usb blaster. There is also chinese usbblaster clone that use original hardware setup (FT245 + CPLD), so I think the speed will be equal.

author: Christe4nM
author_rank: Unknown
timestamp: July 07, 2013, 08:47:05 pm
content: I've read through the three threads on your FPGA Module, and one thing I still don't get is where in all of this HDL programming has become something as easy as to be aimed at "Arduino-people". It simply isn't, and at least requires a completely different mindset even if "Verilog is similar to C". I really got to say that I think you might be misleading people about the learning curve on HDL.Now, any professional HDL engineer would probably not be bothered by Arduino compatibility. Neither by a board from an unknown manufacturere. They will probably buy directly at their vendor's rep, getting all support they need in the process. For a serious company a €500 devboard is peanuts.So I think you need to aim at hobbyists and the "makers". If you want to provide a quick and easy way to start with HDL, then go for it. Know however that the devboard alone doesn't do it. You need to provide example code, tutorials, prebuild modules, or even better an programming environment that really is like pick 'n place of building blocks.YMMV

author: cthree
author_rank: Frequent Contributor
timestamp: July 08, 2013, 04:12:27 pm
content: Selling an FPGA as a reusable PCB on a chip is great marketing speak, the same I've been hearing for over a decade yet it still hasn't materialized. The market has already decided what FPGAs are for and unfortunately for you I fear is that they are still right.FPGA learning tools appeal to advanced electronics designers who want to move up to master level. Face it, if you can program an FGPA using Verilog or VHDL you aren't a hobbyist anymore, you're a pro.I think you've misread the market a little. I hope I'm wrong for your sake and I with you the best of luck but HDL only looks easy to you because you know it. The syntax might not be too complicated for someone who knows a moderate level of C but the concepts and principles are completely different. HDL is not software.

author: nctnico
author_rank: Super Contributor
timestamp: July 08, 2013, 07:25:17 pm
content: I disagree. I've started working with programmable logic when I was still a teenager so its not something you can only do after years of study. If your designs get more complex a lot of strategies for developing software apply to writing HDL as well. There are two pitfalls: thinking you can just start coding and get somewhere and forgetting HDL code runs parallel. A lot of people see an FPGA as something that needs to be controlled down to te last bit. That may be true if you need the maximum speed or minimum size (like programming in assembly) but you can easely get a working design without caring much about how it works at a low level, size and speed.There is a lot of FPGA code out there (see opencores) and if you don't need to push an FPGA to the edge regarding clock speed then you can do a lot in a short time by using & modifying existing code. If an FPGA module comes with some good examples (maybe an embedded processor with peripherals) then I certainly see an audience which can benefit from it.

author: thinlayer
author_rank: Contributor
timestamp: July 09, 2013, 01:44:37 pm
content: Guys, thanks for all the feedback. I have got a lot of example code on the wiki.Www.thin-layer-embedded.com, just go to the helix-4 page. Nios2 in almost all of them, and a lot of shield examples like stepper motors, pwm controllers, i2c for touch shield, etc. I'm not good enough at letting people know its there.I think almost everyone learns c first. We love it and are resistant to anything different. Verilog is easy too IF you learn it first. I had to help my fae with C from time to time, she learned vhdl first and struggled with thinking in C. Just human nature.

author: nctnico
author_rank: Super Contributor
timestamp: July 09, 2013, 03:50:32 pm
content: I can get worst. During my EE study we had to use a modified C compiler to make a behaviour model (test vectors) of digital logic to be implemented in a chip and an FPGA. I found that so confusing it took me quite an effort to finish the project on time. I actually kinda hacked the school's server (HP-UX) so I could work on the project from home!