Spartan 3 kit jtag problem

[lmtg]

I am just starting to learn how to load to an fpga. I am using a spartan 3 kit with digilent jtag-parallel cable. Problem is, my latop doesn't have a parallel port. So I got a usb to parallel cable but Xilinx still fails to detect the jtag cable .HELP!! :s

 

[Jack// ani]

Are you using USB-to-Parallel converter cable or an USB JTAG cable?

 

[lmtg]

USB to parallel converter cable with parallel jtag..

 

[P4R4V4C4]

Hi!
I've had the same problem when i started programing my coolrunner2 CPLD that also uses JTAG-parallel cable.
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...
Solutions? Well, you can find real USB-parallel port convertors, they're not just a cable, they have the aditional circuit required, but they are quite expensive. I've even found some webpages where they tell you how to do it yourself!
I'm sure there also exist PCI cards for laptops that have the parallel port...
But i guess the easiest and quickest way is not to use a laptop, but a PC with parallel port! That is what i did, but just because i needed the parallel port for other applications, but in your case, if you only need the parallel port to programm your Spartan, i would suggest you buy a jtag-usb programmer cable (you can find them in the Xilinx web page), it will save you many headaches!

 

[bigdogguru]

P4R4V4C4 is correct, reduce your possible points of failure. The parallel port can be quite finicky to deal with, the are five possible modes of operation: Compatibility, Nibble, Byte, EPP (Enhanced Parallel Port), and ECP (Extended Capabilities Mode). Then throw an adapter or two in the fray and you really have a nightmare on your hands. Besides digilent has USB to JTAG cables for as little as $40, although they require the use of their Adept 2.0 Software which is free to download. If you desire a Xilinx compatible USB to JTAG cable, there are multitudes available for $75 to $100. And then consider that the standard DB25 parallel port is becoming virtually extinct with laptops and the newer desktops.