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First Xilinx FPGA board design,what to choose?

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Full Member level 5
Jan 1, 2005
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nu horizons avnet which choos

i would like to design first FPGA board soon,for experimenting with VHDL doing custom microprocessors.. which device do you advice me to select? Virtex5,4? Spartan? which chip? i am also planning to place a Microcontroller on the board and interconect with FPGA. and also where online can i get all those components including Jtag cable at good price? (digikey etc..are all expencive. and doesnt have FPGA things) thanks

Added after 26 minutes:

i just found on some website that JTAG cable is about 300$! is it possible? or i am looking at something wrong? why would Jtag-USB cable cost so much? huh? just a cable with little circuitry inside!

cuz the one who designs board from scratch is a way much ahead of the one who buys it. and it wont be expencive... and i have friend EE who would help in design. but what about Jtag cable?

Added after 3 minutes:

yeah, found from same website that Jtag-USB programming cable costs $37.95. so i will connect it directly to the chip as i see...

Added after 4 minutes:

a little confused.. the Jtag cable from Digilent can program any Xilinx device... only on THEIR boards?? or i can design my own any type of board, place any Xilinx chip there and program it with this cable?

You would need extra components to use the USB cable. You should also check out the Xilinx parallel cable for $99. For the parallel cable, you directly connect the JTAG pins to the FPGA. I am currently desiging a FPGA board using a Spartan 3AN part which is a FGG676 package.

Good luck in your board design.

Difficult to suggest a suitable FPGA without knowing more about your project. Some microprocessor cores (such as PicoBlaze) fit into a tiny FPGA. Even the 32-bit MicroBlaze with hardware floating-point fits into the small XC3S200 on the Xilinx/Digilent Spartan-3 Starter Kit.

The Virtex devices are all BGA, and require somewhat critical PCB construction. A Spartan-3E (or some other Spartan-3) is more forgiving, and some packages can be hand soldered. They aren't as powerful as Virtex, but are much cheaper and perhaps a better choice for a first project.

Xilinx's two major distributors are Avnet and Nu Horizons. Ordering from them is almost as easy as DigiKey, if you know the part number.
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Xilinx's iMPACT software talks to several Xilinx cables: the old Parallel Cable III, Parallel Cable IV ($125 US), Platform Cable USB ($199 US), and the old MultiPRO. The Parallel Cable IV and Platform Cable USB are fast, expensive, and proprietary (no cheap clones). The Parallel Cable III is easy to find cheap clones, or build yourself. I don't know about the MultiPRO.

Other USB-JTAG products exist (such as from Digilent), but they require their own download software, and generally won't work with Xilinx software such as iMPACT and ChipScope.

Xilinx's iMPACT can be configured for a custom JTAG chain. I would expect Digilent's USB-JTAG products (and other company products) to be configurable too, but I've never tried them.


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