Interfacing Protocol for FPGA

Other than Serial Peripheral Interface protocol which interfacing protocol can be used for short distance communication for Field Programmable Gate Array Boards?


  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2015-10-29 - 14:50:55
    Ummm... which one?
    The situation with FPGA boads is that each manufacturers has several generations of chips and the serial peripheral interface has evolved.

    For instance, the Latice XP2 Brevia requied both a RS232 to program and a Parallel interface, but the Latice XP2 Brevia2 merely handles a USB device to do the same.

    Altera started with a USB Blaster that converted to JTAG programing interface, but now some boards have the USB on-board.

    Okay, I admit I have been talking programing interface, but the newer boards use the same USB for serial peripheral interface as one option. If that is not what you need, the FPGA will allow you to do serial peripheral interface to GPIO pins, synchronous or asynchoronous. Some even provide specific GPIO with pullup resistors built-in for SPI.

    Can't do much unless you have an idea specifically about what you want or need.

    Just try to understand that it is not merely the FPGA chip's resources, it is how the particular board you buy is wired. For instance, the BeMicroCVA9 seems like a good deal with the Cyclone V A9 chip on board, but the 40 pin Terasic headers are not fully supported, so there is actually only limited GPIO and limited compatiblity with Terasic daughter boards.

    All these guys are positioning stuff to get you to buy more expensive stuff to get all that you desire. But you can buy a cheap board, accept that you did not get it all and begin to learn how to shop. That's what I did.

    Actual serial interface configuration is somewhat flexible. If you desire traditional TTL signals, they can be done often at 3.3VDC or 2.5VDC. If you desire more exotic faster serial such as LVDS, that too can be done. But much of this has to be explored in Verilog, VHDL, and with the specific board you have.

    Generalizations are not not much use. Altera has one way of providing a code library to help you build these, Lattice has another way. And I am sure all the others try to make their way rather special.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2015-10-31 - 09:05:50
    This reply may make a lot more sense...
    I am not sure what you need or want.

    Start out with FPGAs by looking at what the provided software does. That includes software libraries of interfacing code.

    Every maker of FPGA provides software for programing that includes a library of modules that can be included internally, or for interfacing. Just about anything you desire in serial or parallel interfacing should be possible.

    If you need something specific, you may have to download and install that software to confirm availablity for that brand. Altera's Quartus II V15.0 is supposed to work in Windows and Linux, but it is easier to install in Windows. Latice's Diamond IDE is supposed to work in Windows and Linux, but simulation support is absent in Linux. So, it seems using Windows is a bit easier to get started.

    But remember that the actual brand, chip, and board are big factors in getting what you want to work. Other than serial, there is parallel. That's about it. Some newer parallel interfacing for video is being done in LVDS.
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