• XuLA2-LX25 image 15
  • XuLA2-LX25 image 15
  • XuLA2-LX25 image 16
  • Open-source design
  • 32 MByte SDRAM
  • 8 Mbit Flash
  • microSD card socket
  • 3.3 & 1.2V regulators
  • 40-pin interface
  • 12 MHz oscillator
  • PIC 18F14K50 micro
  • USB 2.0 port
  • Auxiliary JTAG port
  • Works with the XSTOOLs software
  • Works with XILINX ISE and WebPACK
  • Works with XILINX iMPACT and ChipScope (requires Xilinx JTAG cable)

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Current rating: 3.9

XuLA2 - It's the same size, only BIGGER!

I know that sounds like something Yogi Berra would say, but, in this case, it's true! With the XuLA2-LX25, we took everything you loved about the original XuLA and made it bigger, except for the size (still a miniscule 2" x 1"). Here's how the XuLA2-LX25 stacks up against the XuLA-200:

XuLA-200 XuLA2-LX25
FPGA Logic Cells 4032 24051 Build bigger circuits!
RAM (Kbits) 316 1165 Use larger buffers!
Multipliers 16 38 Do even more DSP!
DCMs 4 4 The same digital clock managers...
PLLs 0 2 …but also phase-locked loops!
SDRAM 4M x 16 16M x 16 More external RAM!
Flash (Mbits) 2 8 More Flash for bigger bitstreams!
SD Card No Yes Store lots of data (or an OS)!
Inputs/Outputs 33 / 27 33 / 33 Every pin is now an I/O pin!
Size (mm) 51 x 25 51 x 25 Same footprint!
Weight (g) 8 9 Gained a bit of weight.
OSHW License Yes Yes Still completely open!
Price $55.00 $119.00

Bigger board, same philosophy.

Like the XuLA, the XuLA2-LX25 is built to provide just the things you need so you can spend your time adding the features you want. It crams a 1,500,000-gate FPGA, 32 MByte SDRAM, 8 Mbit Flash, microSD memory card, two voltage regulators and a supervisory microcontroller into a 2" x 1" footprint (51 mm x 25 mm for you metric guys). Just plug the XuLA2 into your circuit and connect a USB cable to download and test your design. Once you have your design just the way you want it, you can program it into the Flash and the XuLA2 will load it whenever power is applied. It's really that simple.

It's not perfect — we left that up to you.

We've learned over the past twenty years that we can't anticipate everything you want. And we don't have the resources to design and build every board variation you can think of. So we gave up and made the entire XuLA2 design open-source. All of it: firmware, bitstreams, schematic, PCB layout, documentation — everything! If you don't like what we built, you can re-design it and build it your way. And you can sell it to others free-and-clear of any royalties. (But you have to open-source your design just like we do.) And as others do this, you may find someone has built a version of XuLA2 that is perfect for you.

Now what?

Now it's up to you. You can read the FAQ that follows to get more information, and peruse the XuLA2 manual for all the details. Send us an email if you can't find an answer to your question. Then decide if you want to keep forcing your designs into an inflexible system, or if you'd rather take the responsibility to freely build a solution that fits.

It's really that simple.


I ordered a XuLA2 and all I got was a board. No software? No cable? No fancy box!?

When you order a XuLA2, all you get is the board. That's it. Take a look at the related products on the left if you need a software CD, cables, etc. As for the fancy box, well, sorry about that. Think of it as "saving the environment".

What kind of instructions are there for using the XuLA2?

We are currently writing and releasing an open-source book that shows how to use the XuLA with the Xilinx ISE WebPACK software to do FPGA designs. There are also some pre-built projects for the XuLA2.

How does the XuLA2 get power?

The XuLA2 can get power through the USB port or directly through one or more of the voltage supply pins on its prototyping header. Or you can use a combination of both methods.

Only a 12 MHz oscillator? That's kind of slow!

That's just the frequency of the clock going into the FPGA. The Spartan6 FPGA contains Digital Clock Managers (DCMs) that can multiply the frequency of the input clock up to 384 MHz (32x). The DCMs also have dividers so you can generate a wide range of clock frequencies to use in your designs. And you can cascade DCMs together to generate even more frequencies.

How do I program the FPGA?

We provide the XSTOOLs software utilities that let you download bitstreams to the FPGA or serial configuration flash, download and upload the contents of the SDRAM, and run diagnostics to test the health of the XuLA2. All that is required is a standard USB A-to-miniB cable.

Can I use Xilinx's iMPACT, ChipScope and EDK tools with this board?

Yes, but you will need a Xilinx or third-party JTAG cable to connect to the XuLA2's auxiliary JTAG port.

How long does it take to download a bitstream?

About a second if you are downloading a bitstream directly to the FPGA. Downloading into the Flash takes a bit longer, but it's still less than a minute.

Do I have to program the Flash every time I want to test my design?

No. When you are developing your design you will usually download your bitstream directly into the FPGA. You download the bitstream into the Flash after the design is done and you want to remove the USB cable from the board and have the FPGA configure itself from Flash whenever power is applied.

Can I use the Flash for general-purpose data storage?

Yes, but it's probably better to insert a microSD memory card into the socket on the board and use that for data storage. Then you can have gigabytes of data!

Do you include a microSD memory card with the XuLA2?

No, we provide a microSD card socket, but it's up to you to get your own memory card. That gives you more flexibility to choose the memory size and speed you want, and you'll probably get a better deal on it than you would buying directly from us.

How do I use the SDRAM in my design?

We provide a controller interface that makes the SDRAM look like a static RAM to your application.

How do I get data in and out of the SDRAM?

The XSTOOLs software provides both command-line and GUI-based programs for transfering data between the PC and the XuLA2 Board.

How much power does the XuLA2 Board need?

It's impossible to list a meaningful number for power consumption of the XuLA2 Board because it's almost entirely dependent upon the circuitry you load into the FPGA. If you utilize 99% of the FPGA's logic and clock it at 200 MHz, you could be looking at 6 A of current. But if you don't load the FPGA at all and just power the board with nothing going on, it draws around 65 mA.

Mainstream FPGAs aren't really meant for low-power applications unless they can be structured so the FPGA is turned on every so often, does a massive amount of computation in a short burst, and then gets powered off until it's needed again.

What does the prototyping header look like?

The prototyping header consists of two rows of 0.1"-spaced pins separated by 0.9".

If I use a XuLA2 Board in my product, do I have to open-source my entire product?

Not if you just insert a pre-built XuLA2 Board into a socket in your product. In that case, your product is similar to a software application that uses the XuLA Board like a library of precompiled functions. The application doesn't have to be open-sourced and neither does your product.

The USB driver won't install on Windows 8!

Some customers install the XSTOOLs software under Windows 8 but can't program their XuLA2 boards because the USB driver is missing. Windows 8 can be really strict about installing drivers even for such well-known drivers as libusb. To get around this problem, the XSTOOLs installer places a utility called zadig.exe in the installation directory. Once you have the XSTOOLs installed, run zadig.exe and then plug in your XuLA board. You should see a screen like this:

Just 1) select the libusb-win32 driver and 2) click on the Install Driver button. That should do it!

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