Looking for an extremely cheap FPGA board (in quantity, academic use)

Hi all,
I'm looking for a sub-$20 FPGA board (including everything needed to actually use it).
Requirements:
   * The device must have reasonable free software that can 
     handle schematic capture and Verilog (Altera and Xilinx
     would be easily sufficient).
   * Can manage at least 1K gates and 20 flip-flops.

Strongly desired:
   * At least one debounced button useable on a GPIO line (not reset
     for example)
   * At least six switches readable by the FPGA.
   * At least six LEDs writable by the FPGA.
   * At least four GPIO pins that are reasonably accessible.
   * Actually costing closer to $10.
   * Can power off of USB without any other supply.
   * Can manage at least 5K gates and 50 flip-flops.


Would prefer:
   * At least twice as much I/O as described above.  More is better.
   * Compatible at some level with some larger FPGA line 
     (Altera DEx line in an ideal world).

I'm going to go vendor shopping in a few weeks, but I thought I'd see 
if anyone knows of anything close to this that's on the market.  

We'd be looking at around 5K-15K ordered, all for academic purposes.
Failing finding a board, we are willing to design and manufacture our
own (as a far second choice).  So suggestions on parts would be welcome.

Also, any thoughts on using a cheap microcontroller to emulate 
an FPGA would be of interest.

I've found some things that aren't all that close.
 * Digilent C-Mod -- $22 in quantity of 1, needs external programmer, 
   no I/O on-board AFAICT.
 * Polmaddie2.  No switches, way too much $$$, but pretty good otherwise.
   Way more GPIO/FPGA than we need.

 
Thanks in advance,
Mark

On 9/9/2012 12:20 PM, brehob@gmail.com wrote:
> Hi all,
> I'm looking for a sub-$20 FPGA board (including everything needed to actually use it).
> Requirements:
>     * The device must have reasonable free software that can
>       handle schematic capture and Verilog (Altera and Xilinx
>       would be easily sufficient).
>     * Can manage at least 1K gates and 20 flip-flops.
>
> Strongly desired:
>     * At least one debounced button useable on a GPIO line (not reset
>       for example)
>     * At least six switches readable by the FPGA.
>     * At least six LEDs writable by the FPGA.
>     * At least four GPIO pins that are reasonably accessible.
>     * Actually costing closer to $10.
>     * Can power off of USB without any other supply.
>     * Can manage at least 5K gates and 50 flip-flops.
>
>
> Would prefer:
>     * At least twice as much I/O as described above.  More is better.
>     * Compatible at some level with some larger FPGA line
>       (Altera DEx line in an ideal world).
>
> I'm going to go vendor shopping in a few weeks, but I thought I'd see
> if anyone knows of anything close to this that's on the market.
>
> We'd be looking at around 5K-15K ordered, all for academic purposes.
> Failing finding a board, we are willing to design and manufacture our
> own (as a far second choice).  So suggestions on parts would be welcome.
>
> Also, any thoughts on using a cheap microcontroller to emulate
> an FPGA would be of interest.
>
> I've found some things that aren't all that close.
>   * Digilent C-Mod -- $22 in quantity of 1, needs external programmer,
>     no I/O on-board AFAICT.
>   * Polmaddie2.  No switches, way too much $$$, but pretty good otherwise.
>     Way more GPIO/FPGA than we need.
>
>
> Thanks in advance,
> Mark
>
The closest I've seen is a number of Lattice eval boards like the
MachXO2 "Pico" board for about $29.  I've always suspected that the
price of these boards is already somewhat artificially low in order
to win seats for their devices.  It's not clear that you will get
a better price in volume, but I would think Lattice is a good place
to start for low cost FPGA's or boards.

Regards,
Gabor

On Sun, 09 Sep 2012 09:20:03 -0700, brehob wrote:

> Hi all,
> I'm looking for a sub-$20 FPGA board (including everything needed to
> actually use it). Requirements:
>    * The device must have reasonable free software that can
>      handle schematic capture and Verilog (Altera and Xilinx would be
>      easily sufficient).
>    * Can manage at least 1K gates and 20 flip-flops.
> 
> Strongly desired:
>    * At least one debounced button useable on a GPIO line (not reset
>      for example)
>    * At least six switches readable by the FPGA. * At least six LEDs
>    writable by the FPGA. * At least four GPIO pins that are reasonably
>    accessible. * Actually costing closer to $10.
>    * Can power off of USB without any other supply. * Can manage at
>    least 5K gates and 50 flip-flops.
> 
> 
> Would prefer:
>    * At least twice as much I/O as described above.  More is better. *
>    Compatible at some level with some larger FPGA line
>      (Altera DEx line in an ideal world).
> 
> I'm going to go vendor shopping in a few weeks, but I thought I'd see if
> anyone knows of anything close to this that's on the market.
> 
> We'd be looking at around 5K-15K ordered, all for academic purposes.
> Failing finding a board, we are willing to design and manufacture our
> own (as a far second choice).  So suggestions on parts would be welcome.
> 
> Also, any thoughts on using a cheap microcontroller to emulate an FPGA
> would be of interest.
> 
> I've found some things that aren't all that close.
>  * Digilent C-Mod -- $22 in quantity of 1, needs external programmer,
>    no I/O on-board AFAICT.
>  * Polmaddie2.  No switches, way too much $$$, but pretty good
>  otherwise.
>    Way more GPIO/FPGA than we need.
> 
> 
> Thanks in advance,
> Mark

When you get as far as vendor-shopping, don't forget Avnet.  I think most 
of their stuff starts at $100 and goes up from there, but you never know.

Ditto SparkFun, for the opposite reason -- if they had anything FPGA, 
they'd probably have something in the price range you want.  But I 
wouldn't bet anything that they actually have that.

-- 
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

Gabor wrote:
> The closest I've seen is a number of Lattice eval boards like the
> MachXO2 "Pico" board for about $29. I've always suspected that the
> price of these boards is already somewhat artificially low in order
> to win seats for their devices.  It's not clear that you will get
> a better price in volume, but I would think Lattice is a good place
> to start for low cost FPGA's or boards.

The Pico board has many unecessary components, like the FTDI chip,
accelerometer and the 1.2 V voltage regulator.

There are Lattice FPGAs with 3.3 V only. The LCMXO2-640HC-4TG100C for
$4.72 at Digikey should be sufficient. It has 640 LUTs, so it should be
possible to implement 1k gates with it (because sometimes multiple gates
can be integrated in one LUT). 50 flip-flops is no problem at all.

For the USB connection you could use the MC9S08JS16L, which I've used
for http://www.frank-buss.de/joystickadapter/ and which costs less than
$1. This microcontroller can program the FPGA at boot time, if you add a
SPI flash for $2, or without a Flash just from the USB port. Crystal
oscillator, DIP switches, LEDs etc. should be less than $10 for all
parts, so $20 for a fully populated PCB should be possible, if you
develop it yourself. A smart student could do it, to save development cost.

-- 
Frank Buss, http://www.frank-buss.de
electronics and more: http://www.youtube.com/user/frankbuss

// Snip

It would seem that if this board is for "academic use" you could have a 
student design this for you and as a class project have it built by the 
students.

You really need to pick a chip that meets your "class room" requirements 
for functionality first.

Not cost first.

Also,

What do you expect to teach.

Just like in any product development, What do you expect to do with this 
thing, who do you expect to sell it to.

My $0.02

hamilton

On Sep 9, 5:30=A0pm, Frank Buss <f...@frank-buss.de> wrote:
> Gabor wrote:
> > The closest I've seen is a number of Lattice eval boards like the
> > MachXO2 "Pico" board for about $29. I've always suspected that the
> > price of these boards is already somewhat artificially low in order
> > to win seats for their devices. =A0It's not clear that you will get
> > a better price in volume, but I would think Lattice is a good place
> > to start for low cost FPGA's or boards.
>
> The Pico board has many unecessary components, like the FTDI chip,
> accelerometer and the 1.2 V voltage regulator.
>
> There are Lattice FPGAs with 3.3 V only. The LCMXO2-640HC-4TG100C for
> $4.72 at Digikey should be sufficient. It has 640 LUTs, so it should be
> possible to implement 1k gates with it (because sometimes multiple gates
> can be integrated in one LUT). 50 flip-flops is no problem at all.
>
> For the USB connection you could use the MC9S08JS16L, which I've used
> forhttp://www.frank-buss.de/joystickadapter/and which costs less than
> $1. This microcontroller can program the FPGA at boot time, if you add a
> SPI flash for $2, or without a Flash just from the USB port. Crystal
> oscillator, DIP switches, LEDs etc. should be less than $10 for all
> parts, so $20 for a fully populated PCB should be possible, if you
> develop it yourself. A smart student could do it, to save development cos=
t.
>
Yep, I'm guessing we will have to design it ourselves, but I'm hoping
to find something off-the-shelf (always ideal if what you want already
exists).  That said, we'll probably need to design it ourselves so
we'll need to find parts. Your suggestions are a good starting point,
thanks!  The  LCMXO2-640HC-4TG100C is a bit more than we need in terms
of I/O and memory, but otherwise looks nearly ideal.

Still hoping a board exists...

Thanks,
Mark
> --
> Frank Buss,http://www.frank-buss.de
> electronics and more:http://www.youtube.com/user/frankbuss

On Sep 9, 5:42=A0pm, hamilton <hamil...@nothere.com> wrote:
> // Snip
>
> It would seem that if this board is for "academic use" you could have a
> student design this for you and as a class project have it built by the
> students.
Yep, that's the backup plan.
>
> You really need to pick a chip that meets your "class room" requirements
> for functionality first.
>
> Not cost first.
Sadly, the top-level requirement is likely going to be cost.  That is,
we'll have a fixed budget and need to do as much as we can within that
budget.  I agree it's not the ideal way to proceed, and the amount for
the fixed budget is unclear at this time ($10-$20/unit is a safe bet
though).

What we are doing right now is exploring if we can possibly do the
labs we want to do given the budget we think we have.  The key
question is "is this doable given the cost constraints", where "this"
is mildly flexible (thus the I/O constraints being only rough).
>
> Also,
>
> What do you expect to teach.

http://www.eecs.umich.edu/courses/eecs270/labs.html is what we _want_
to do.  Right now on a DE2 board.  The labs cover the standard basics
as well as a bit of interfacing.  Some parts of the labs as written
are the way they are because of the board we have.

>
> Just like in any product development, What do you expect to do with this
> thing, who do you expect to sell it to.

What: the labs above (with some reduced I/O requirements including
losing the 7-seg displays).
Who: Anyone taking the class on-line, including those with extremely
limited budgets (third-world).

Mark

>
> My $0.02
>
> hamilton
Thanks!

On 9/9/2012 5:30 PM, Frank Buss wrote:
> Gabor wrote:
>> The closest I've seen is a number of Lattice eval boards like the
>> MachXO2 "Pico" board for about $29. I've always suspected that the
>> price of these boards is already somewhat artificially low in order
>> to win seats for their devices.  It's not clear that you will get
>> a better price in volume, but I would think Lattice is a good place
>> to start for low cost FPGA's or boards.
>
> The Pico board has many unecessary components, like the FTDI chip,
> accelerometer and the 1.2 V voltage regulator.
>

Actually the FTDI chip is the programming adapter as well as a serial
port for this board.  The original desire was for a board that came
with everything required to program it.  In this case the PicoBoard
is powered by USB, and programmed with the same USB adapter.  It
may not have needed the serial port, but I'll take it as an added
bonus.

All of the analog stuff is just so they can demo the "low power"
of the MachXO2 part.  You could always ask for partially stuffed
boards if you want to get into a volume deal.  The capacitive buttons
are also unnecessary, but better than no buttons.

In any case an FTDI chip (maybe a simpler one than that on this board)
is usually a good idea when you want the board to be programmed without
an extra JTAG cable (usually much more expensive than these boards).

> There are Lattice FPGAs with 3.3 V only. The LCMXO2-640HC-4TG100C for
> $4.72 at Digikey should be sufficient. It has 640 LUTs, so it should be
> possible to implement 1k gates with it (because sometimes multiple gates
> can be integrated in one LUT). 50 flip-flops is no problem at all.
>
> For the USB connection you could use the MC9S08JS16L, which I've used
> for http://www.frank-buss.de/joystickadapter/ and which costs less than
> $1. This microcontroller can program the FPGA at boot time, if you add a
> SPI flash for $2, or without a Flash just from the USB port. Crystal
> oscillator, DIP switches, LEDs etc. should be less than $10 for all
> parts, so $20 for a fully populated PCB should be possible, if you
> develop it yourself. A smart student could do it, to save development cost.
>

On 9/9/2012 5:09 PM, Mark Brehob wrote:
> On Sep 9, 5:42 pm, hamilton <hamil...@nothere.com> wrote:
>> // Snip
>>
>> Not cost first.
> Sadly, the top-level requirement is likely going to be cost.  That is,

This is always the argument with commercial products too.

But you still need to have a spec!

Lets be real, your on a shoestring budget with a DE2 diet ;-).

The PCB and pin headers will burn thru half of your $20.

A board with one chip onboard (i.e. LCMXO2-256HC-4TG100C $3.40 100s),
a USB connector, a 3.3V voltage regulator, a few loose passive parts and 
you are done.

I would enjoy building a board like this, but I do not have an 
advertising budget to pay for it.

Digikey part#		ea@100pcs total

220-1425-ND		3.40	340.00	LCMXO2-256HC-4TG100C
ED90341CT-ND		0.92	 92.00	CONN RECEPT MINI-USB TYPE B SMT
497-1236-1-ND		0.287	 28.74	IC REG LDO 3.3V .95A D-PAK
PCB (2.5" x 2.1")	8.50	850.00	PCB I had quoted with PCBcart a few weeks ago
A26509-40-ND		1.402	140.25	CONN HDR BRKWAY .100 40POS VERT

			total	1,450.99

Here is $14.51 per board for most of the components.

There may be some savings here, but the remaining passive components 
will take care of that.

If I were to build a board like this, I would have to charge 3x the cost 
of parts to make it worth my while.

And I would require you to buy all 100.


On the other side of the coin:

Digikey part#	Qua = 1
220-1298-ND	$29.99	BOARD BREAKOUT MACHXO2

http://www.latticesemi.com/documents/EB68.pdf

Has all you want, and they have an advertising budget.

This sounds like a great opportunity to teach a little entrepreneurship.

This was a fun exercise, maybe you can use it in your class.

I bet you can write on your school letter head and ask for 100 samples 
of each of the parts.

You will still need to design a PCB and have it fabricated.


Good luck

hamilton

I think you're in luck...

I was browsing around earlier today trying to figure out if I could do realtime video-rate JPEG encoding on a DSP instead of having to code it up in verilog, and ran across this...

  http://www.nuhorizons.com/development/board.asp?product=Lattice-ICE40LP1K-BLINK-Evaluation-Kit

For $20, you get:

 - 4 capacitive buttons. I guess you still have to 'debounce' capacitive buttons...
 - 63 i/o on breadboard-friendly 0.1" headers. You'll have to supply the headers.
 - can power off the USB
 - has ~1K logic cells (lut+flip-flop)
 - comes with USB cable & software can be downloaded.

Assuming you can solder some headers onto the board, switches can be replaced by jumpers, and 63 i/o is actually really generous at this sort of level. Most of the entry-level boards are seriously miserly in comparison.

On the downside, you'd probably not get much of a bulk discount - I'm guessing they're already cut to the bone at this price...

Just FYI - not a recommendation since I've never used Lattice before, but thought you'd be interested.

Simon