FPGA question

Discussion in 'General Electronics Chat' started by count_volta, Jun 3, 2009.

  1. count_volta

    Thread Starter Active Member

    Feb 4, 2009
    Hey, I want to try building some logic circuits in real life. I never used FPGA's before. I need some advice.

    One of the logic circuits I want to build has 7 functions of 4 variables each. F(x1,x2,x3,x4)... 7 of these.... Each output goes to a separate led. But they all have the same inputs.

    I looked for FPGA's online and found a few, but this is where I need your advice. Will this one for example be able to do what I said above?

    6 Xilinx Spartan XL FPGA XCS20XL-4VQ100C

    Data sheet... http://www.xilinx.com/support/documentation/data_sheets/ds060.pdf

    Or Altera FLEX 6000 Family FPGA 144PIN-TQFP

    All that they are selling is the chip and nothing else, what else would I need to be able to program my logic function into the chip? I don't think it even comes with any cable or anything, they are just selling the chip.

    Are there really cheap starter kits somewhere for people getting started with FPGA's?

    Thank you.
    Last edited: Jun 3, 2009
  2. count_volta

    Thread Starter Active Member

    Feb 4, 2009
    If nobody in General Electronics chat knows about FPGA's, please move this topic to the appropriate part of the forum. I should have done that in the first place.
  3. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    Look at the "Configuration and Test" section of the datasheet that you linked to the question. It gives you the programming options of the parts. Typically, you can use a PROM, which is externally programmed with your code and inserted into the system, or you can have an embedded microprocessor program the FPGA with code loaded into its available memory.

    There is also a family of parts, CPLD, which the parts themselves are programmed and can be in system reprogrammed by way of JTAG cables provided by the manufacturer.

    I think your selected part will be plenty big for your need. It has an estimated logic gate count of 7000-20000 gates, i.e. ANDs, ORs, .... Four variable functions are typically done in a single block.

    I know Xilinx has free software, ISE Webpack Software, for some FPGA and CPLD development. Check its parts limitations before trying, it supports quite a few parts. Try implementing your design there and verify that everything fits in the parts you are looking at.

    I'm sure Altera probably has a similar thing.

    I've used both Altera and Xilinx FPGAs and CPLDs and found them both very good. I would not recommend either over the other. The company I was at flipped back and forth based on price.