zygot

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Status Replies posted by zygot

  1. Regarding https://forum.digilentinc.com/topic/4710-spartan-3-starter-board-help/ and https://forum.digilentinc.com/topic/4784-s3-starter-board-programmer/

    I do not have a second FPGA board - I only have the parallel-2-JTAG adapter-cable that comes with the board. I am wondering if this adapter-cable is still working with modern Laptops USB-Parralel adaptors ?

     

    Do you have any experience ? 

     

    1. zygot

      zygot

      Not really. If an adapter costs as much as CMOD-A7 that I use in the project you might as well buy one of those FPGA boards; then you can replicate the project as presented. If you want to try and get a modern PC working with a parallel port then I suggest that you stick with an OS like Linux. The project that you refer to is a good reference for one way to configure older devices if all of the required signals are exposed to a connector. If you want to save money but have the time there's no reason why you couldn't use a microprocessor to do the programming. A lot of FPGA device embedded in PCBs with a micro are configured that way instead of using a separate flash device.

    2. (See 1 other reply to this status update)

  2. D@n

    D@n    zygot

    Would you rather this as a venue for discussion?  Are you interested in further discussion?

    Dan

    1. zygot

      zygot

      Dan,

      Your last message helps clarify things. 

      As for the individual that you are coaching "image processing" is quite open-ended. Is it a PC or SBC communicating with a sensor? A small FPGA board tied to another FPGA board? You don't need answer those questions as they are mostly rhetorical. But you see my point, without know specifically what one wants to accomplish and what the basic requirements are... mechanical size, power requirements, thermal requirements, environmental... etc, etc, are then it's not possible to offer a solution. I had to look up XuLA2... it's a pretty small FPGA for generic image processing. (I still have one of Xess's first FPGA products sitting in a box somewhere.... though I haven't looked into them for a while). I have a LOT of USB interface experience, often involving a PC host application, and all of them had different requirements and unique FPGA interface design solutions. My only thought here is that starting with a fixed hardware platform and trying to cram a design into it rarely works unless the hardware and supporting software support are geared to that particular design. Successful engineering always starts with defining requirements, proposing a solution platform, working out the data rates of interfaces.... an idea that escapes even tech companies with scores of engineers who should know better.

      For what it's worth I've used FPGA boards from Terasic ( I like their NANO boards for prototyping ), Opal Kelly, Digilent, and of course Xilinx and Altera. I have yet to find a development board that does everything I want, or has the connectivity for any project. The ATLYS from Digilent was a nice product and generally well supported. Unfortunately, Digilent was bought out by NI and has decided that instead of wasting money paying engineers to support their products they will let "volunteers" do it for free in a forum environment.

      If you want to work with USB intelligently you have to get down and dirty into the nitty-gritty details by doing some designs using vendor (FTDI, Cypress, Atmel. etc.) tools. USB isn't the only interface around. 1G ethernet is a fine hose for transferring data, with a MAC or not, between boards or a board to a PC or SBC. The Genesys2 has 4 lanes of high-speed transceivers conveniently connected to DisplayPort connector. And then there's PCIe. Lately, I've been playing with ethernet PHYs and PCIe... haven't decided how to use that Genesys2 yet.  

      I suspect that this particular topic has been beaten to death by now but if you want to communicate further you can reach me at my email. eclektek@dejazzd.com.

       

    2. (See 6 other replies to this status update)

  3. D@n

    D@n    zygot

    Would you rather this as a venue for discussion?  Are you interested in further discussion?

    Dan

    1. zygot

      zygot

      Hey Dan,

      No thoughts on my last contribution to this thread? bill

    2. (See 6 other replies to this status update)

  4. D@n

    D@n    zygot

    Would you rather this as a venue for discussion?  Are you interested in further discussion?

    Dan

    1. zygot

      zygot

      Dan,

      My experience is with FTDI and Cypress USB 3.0 solutions, though I did spend some time testing and re-writing HDL interfaces for the older CY6813A Adept interfaces. It's been my experience that trying to stuff a lot of general purpose options into an endpoint controller is pointless. After all you can do anything you want in the FPGA. If you're trying to connect USB to some other hardware with limited interface options then that's another topic. Better to have a simple fast endpoint controller; and what that means is highly dependent on what it is that you want to do. An issue with the CY6813A Adept is that there is a big penalty in switching from asynchronous mode for small data transfers, such as passing control/status register data, and synchronous mode for large data transfers. At this point you're looking more at PC host software/driver and limitation in the USB protocol than anything that endpoint hardware can address. FTDI has made a business creating simple solutions for USB connectivity without the need for (much) external logic. With simplicity comes limitations. If you want to create an optimal ( which could be throughput or latency centric ) endpoint interface then Cypress is the way to go ( I can't speak to PIC, ATMEL, or other vendor USB endpoint solutions as I don't have much experience with them ) The Cypress FX2 and FX3 design and tools allow for much better customization of their endpoints for A PARTICULAR purpose than any other any other vendor's product that I've looked into. I don't particularly like working with the  Cypress tools but haven't yet found anything to replace it. 

    2. (See 6 other replies to this status update)

  5. D@n

    D@n    zygot

    Would you rather this as a venue for discussion?  Are you interested in further discussion?

    Dan

    1. zygot

      zygot

      D@n,

      Always happy to engage in a useful discussion. It just seemed to me that your post was getting off the initial topic. I really am not understanding what it is that you want to accomplish. Bill

    2. (See 6 other replies to this status update)