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FPGA in a Design

Discussion in 'Electronic Design' started by Joshua K Drumeller, May 20, 2005.

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  1. In college I had the wonderful and thrilling experience to design with
    FPGAs. I have learned a lot working with them. However, the FPGAs we were
    using were in pre-designed boards and we just focused on programming them
    with our assignments. My question is how do you incorporate an FPGA into a
    permanent design of a circuit board?

    The FPGAs we used would lose their programming when the power was
    disconnected. So how would a circuit designer who wanted to use an FPGA in
    their permanent design get around that? Are there FPGAs which you can only
    once from a computer then solder it into a design? Or would you have to
    design a circuit which would load an FPGA every time it is powered up in
    your permanent design? Or something else?

    I have been searching the internet for some time and most of the info I get
    is about FPGA experimental design boards. IF any one can help me out here it
    would be extremely appreciated.

  2. Mook Johnson

    Mook Johnson Guest

    Yes and Yes,

    Actel make anti-fuse technology type FPGAs that you program and soler onto
    the board. Forever that parts will remain as programmed.

    Actels ProAsc is a flash based part that you can program (even setup for
    incircuit programming for field upgrades) and change logic code when you
    need to. Flash retains its memory when powered down.

    Xilinx makes FPGA that load their programming from a seperate EEprom which
    can be programmed and installed in a socket (8 pin dip) for reprogramming.

    Altera is similar.

    Lots of options.
  3. keith

    keith Guest

    SRAM based FPGAs have a non-volitile source for their configuration data.
    Typically this is an external serial ROM (the simplest, but most
    expesive), or a microcontroller with some sort of PROM. One can also
    program through a channel like a PCI bus.

    There are other FPGA technologies that are non-volitile, though they're
    several generations behind the technology curve. SRAM based FPGAs are
    usually done on the same processes as microprocessors and have the
    advantage of that performance.
    As above, one puts a "boot PROM" in the circuit. There are many was to do
    Yes, though they're not the fastest nor densest parts. They're alos a
    PITA to use.
    Generally, yes. It's not a big deal though. The FPGA manufacturers build
    several method of doing this into their devices. Depending on the design
    constraints, one is less painfull than the others. ;-)
    Google "logic jump station". Also look at the Xilinx and Altera sites.
    There is a *ton* of information there.
  4. Ken Smith

    Ken Smith Guest

    You can:

    (A) Never disconnect the power. Using a lithium battery or the like, the
    power can be left on. This is an insane thing to do unless you are
    very worried about security.

    (B) Use a FPGA that loads its data from a PROM that sits next to it.

    (C) Use a FPGA that has a PROM co-packaged with it.

    (D) Use one of the anti-fuse or the like ones.

    (E) Load the code from a micro controller.
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