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Spartan 3E interface Cable

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Junior Member level 2
Jul 21, 2012
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My Spartan 3E Kit has a DB25 connector, which Cable is suitable for interfacing it to my Laptop ?

Can anybody give solution as to which cable should be used to connect Spartan 3E Kit ( having DB25 ) connector to Laptop (having USB) ?

What's the exact name of the kit that you're using?

Actually its a custom made board having Spartan 3E XC3S100E VQ100.
I suppose it is a modified kit, i have got it from a friend so exact details are unavailable for it, I downloaded the program from a PC which has a parallel port through a Paralel Cable having DB 25 at both ends, but now i want to run it through laptop.If required I can send a snapshot of the Kit.

If it's a custom made board - a snapshot won't help.
The PCB schematic is required.

i dont have schematic, the board also has a serial DB9 (FEMALE) port, so can you suggest whether i can use this for connecting to laptop and download program ? , if yes then which cable is required, can local cable: DB9 (MALE) to USB be used ? and will speed affect downloading ?

Without the schematic telling you what the DB9 is connected to you can't determine if you can program or download anything to the board.

i dont have schematic...

Without a schematic or connection table, how to you intend to effectively implement a design?

If you have no idea what FPGA pins are attached to which PCB connections or its surrounding circuit, of what value is it?

Yes, I have got the schematic JTAG interface.pngDB9.png

The most obvious way to communicate with your FPGA will be to implement a UART and connect it to talk over RS232 standard.
The DB25 connector show in your first page of the schematics is not a serial port, but depicts the Xilinx Parallel III (PIII) programing cable. I have attached the Xilinx Appnote discussing the same design and schematic.

CAUTION, connecting the DB25 to a RS-232 serial port of a PC may permanently damage the Spartan 3E XC3S100E or board circuits.

The good news is if you are able to find an older copy of Xilinx ISE and a desktop PC with a parallel port you could possibly program the Spartan 3E, the bad news is you don't have a prayer getting it to work with a relatively recent laptop.

You would be better off purchasing a cloned Xilinx USB Platform Cable programmer clone on eBay.



  • xtp029.pdf
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Well...I'm not sure that they do. Never tried it with the Xilinx device.
But I have used them successfully on other occasions when I had to communicate between a stone-age system and a modern PC.
Sorry if I didn't make it clear...RS232 uses the DE9 connector (not the 25 pin one).

For programming the FPGA with a PC that doesn't have a parallel port you can use this:

Thanks for the reply.. I have read in another post in edaboard I will put it as it is here "The problem is that the USB-parallel cable is not valid because it is not an actual parallel port, it just multiplexes pins, it is still a serial port, it's like a usb conector - DB25 conector, but it doesn't have the real parallel port cirucuitery. And what's more, i guess your laptop doesn't recognize a parallel port, it keeps seeing it as a USB. There's the problem! This kind of cables are normally used only to connect printers to laptops, but nothing else..."

So is this cable which you have recommended useful for programming the FPAG through laptop or is it like the above mentioned case ?
Please Help

You need a "Xilinx Platform Cable USB", otherwise know as a "Xilinx JTAG USB Cable" or just "Xilinx JTAG."

If you search for the above cable on eBay you'll find plenty of genuine and clone examples for sale. You may have to tap into the required lines if there is not an official JTAG port available on your board with flying leads.


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