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FPGA recommendations

Discussion in 'Electronic Design' started by [email protected], Dec 5, 2005.

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  1. Guest

    Hello all,

    I'm looking for an FPGA platform to produce some low-volume designs on,
    and I would like to hear the group's suggestions on manufacturers.

    What I am most concerned about is the flexibility and functionality of
    the programming tools. In other words, whether they're crippled unless
    I pay thousands of dollars for the "full version." I won't be selling
    thousands of units, so I can't consider the software an investment. I
    don't mind paying a reasonable amount for a compiler, but I am not in
    the same market as Linksys and I can't afford what they pay for

    I am currently using Altera flex0k's and quartus, which is free but has
    some fairly minor limitations. I can more or less live with the
    restrictions as they more or less force me to buy a larger chip than is
    necessary but still do basically anything. However, they could pull the
    rug under me at any moment by not licensing the free compiler (it
    requires a new license file periodically.) Is there a better option? I
    recently discovered that Atmel has a CPLD/FPGA line; does anyone have
    experience with it?
  2. Look at Xilinx. They seem to be agressively pursuing your (our)
    market. You can download the software, IIRC the limitations don't kick
    in until you hit the really big expensive parts. The Mentor ModelSim
    requires a node-locked license, but it's free as well (and I think
    Xilinx is working on their own simulation package). Apparently the
    Mentor s/w deliberately runs slower than the $$ package, though, once
    you exceed 10,000 lines of code).

    Also, at least according to my FAE, they deliberately don't go
    overboard on protecting their 'evaluation' software (you can
    de/re-install to get another 'evaluation', he says) because they want
    to sell silicon. They have soft processor cores available (8-bit is
    free in object code) and some of their huge 90nm arrays have a handful
    of PowerPCs littering the corners of the chip in case you need a

    I've found the S/W pretty much bug-free (perhaps not quirk-free) so
    far, though it will tax the speed of the best computer you can buy. I
    have not used Altera's software, so I can't compare.

    Best regards,
    Spehro Pefhany
  3. David Brown

    David Brown Guest

    Altera is similar, except that they already have simulation software
    (and have had for a long while, I believe). I've never bothered with
    the free ModelSim for Altera Quartus.

    All major FPGA/CPLD players use node-locking on their tools, and all
    (that I know of) have some sort of time limitation on their free
    versions. Altera paid-for licenses are permanent - I'd guess the same
    applies to Xilinx.

    Altera and Xilinx are by far the biggest players in the fpga market -
    there are others in the CPLD line (Lattice has some nice parts). But
    for fpgas, you are best with A or X unless you want a more specialist part.
    I haven't done more than play around with X's software, and that was a
    while ago. But it struck me that X tools were made from a collection of
    different tools bundled together, while A tools were much more
    integrated. This made the Altera tools more consistent - I think they
    are a definite selling point for Altera.

    Both A and X have soft processors, available under similar terms and
    with similar functionalities, although I personally think the Altera
    soft processor is a better system. Altera have effectively dropped
    their hard processor core line, having concluded that in virtually all
    cases, you are better with either a flexible soft processor or an
    external processor. Xilinx PPC parts are well publicised, but are a
    very small market.

    The main difference between A and X, however, lies in their reputation
    for availability. I have never had to get hold of Xilinx parts, so I
    can't speak from personal experience, but the appearance seems to be
    that when Altera announce availability of a new part, you can order it.
    When Xilinx announces availability of a new part, you can get samples
    in about a year or so. If you look at the comp.arch.fpga newsgroup, you
    will see regular threads complaining about availability of X parts or
    asking when and where they can be bought.

    Of course, opinions vary wildly, and depend on many factors (your target
    applications, the quality of your distributors, personal experience).
    But either way, drop the old Flex devices and go for Cyclone II /
    Spartan 3 (or Stratix II / Virtex for the high end) and the latest
    version of the tools.
  4. On 6 Dec 2005 16:08:58 +0200, the renowned David Brown

    The Xilinx free Webpack software is not node locked, only Modelsim,
    and it doesn't 'call home'. I think it's permanent, but I've not
    verified this. The stuff I downloaded a couple of years ago still
    worked a few weeks ago, even Modelsim.
    That was my conclusion.

    My FAE said that the best Xilinx deal was typically with the latest

    They seem to be following certain aspects of Microchip's business
    model-- leaving higher prices on old silicon, inexpensive development
    tools widely distributed, etc. Of course FPGAs use close to
    state-of-the art silicon processes so they can't go with surplus
    memory fabs for production-- they are fabless. Don't know much about
    Altera. Similar?

    Best regards,
    Spehro Pefhany
  5. David Brown

    David Brown Guest

    Very similar. Altera and Xilinx decisions are often based on small
    details or personal preferences or experience - the differences are
    small. I just posted so that the OP wouldn't think there was something
    special about Xilinx parts or tools, and to give some balance.
  6. IME, Xilinx has better I/O. Of course, they bought and killed the
    company who's part I was using, for their I/O IP. The project was
    scrapped and I had to do a complete redesign with 'X'. A year and
    a complete board design gone, poof. I took another year to get
    Virtex-E parts (with the I/O I needed).
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