Just because I don't think a board will be adequate doesn't mean I won't take a close look. My colleague was wanting to put an enhanced 805x core on this board, but I don't see it ... yet ... as being adequate because of the demands of the interfaces. A simpler board would work better, at least to my way of thinking, I believe. I'd prefer to have a board with just the oscillator, an FPGA, and a PROM capable of booting the entire device if it were 100% utilized, which it would never be, along with access to every unused pin on the FPGA, either through on-board connectors to attachable wire-wrap/prototyping boards (not those solderless breadboards, though) or common ribbon cable connectors for attaching external hardware.

As Mike said, it's got too much stuff on it and no way to dispose of it if you don't want to use it. The internal memory is inadequate for much useful work as code storage and data RAM, though the 32Mx16 DDR SDRAM would be useable if it turns out that you can use DDR SDRAM in your design, and you can get at all-too-few of the many pins the XC3S500E has. It does appear to have sufficient FLASH (128 Mbit) and external DDR SDRAM resources to facilitate operation of the device as a host for MicroBlaze soft-core and running LINUX, and it has USB, Ethernet, Serial I/O, and an on-board LCD, as well as a PS2 and a VGA connector, though I'm not at all sure how one should exploit the latter. I have doubt very much that the FPGA is adequate to load a soft CPU on the order of MicroBlaze together with the facilities needed to exploit the PS2 connector, VGA connector, serial ports, USB (though it has a Cypress controller), Ethernet (though it has an SMSC 10/100 Mbps PHY)

It uses a rather fragile 100-pin Hirose FX2 plug connector that are incompatible with conventional ribbon cables for purpose of connecting to off-board circuitry. There's no prototyping area of any sort, so what you can do is pretty much what THEY (Digilent's designers and XILINX) decided you should do, and little else. You can, of course, buy one of their wire-wrap boards and roll-yer-own circuit on that, with the associated interconnnection (timing, signal quality) penalties.

If you want information about this board, it's very scanty. There is no schematic, no documentation that's directly applicable to this board at all, and a 2004 (very much outdated) book on programmable logic that may be helpful in using Digilent's pre-2004 boards and XILINX's products of that era. I suppose I can get the wire-wrap board, subsequently call Clint Cole at Digilent, and learn the expansion connector pinout, but I'm quite sure that, aside from the demo modules, I'll be quite unable to attain any benefit from its use. I don't know why they don't have a support CD or documentaiton.

Their documentation for previous boards I obtained from them was pretty scanty, too, but they were so simple that (a) I was able to use them, and (b) I could use their documentation to help me extract useful work.

Their (Digilent's) early boards, e.g. the original XC2 board, and the later XC2XL had a wire-wrap area, documentation, and on-board Parallel port connector to facilitate programming. Their later boards, e.g their Spartan-II, and various IIE boards had documentation, some of which was incomplete, and some of which was simply incorrect, but their features didn't get in the way. The FPGA boards came with programming cables that adapted the parallel port to the board's JTAG connector. Their early wire-wrap board, though convenient and inexpensive, had erroneous silkscreen which could mislead one into making severe and destructive errors.

The FPGA boards I have lack sufficient on-board PROM, with one exception, to utilize the FPGA fully. This tendency seems to have been continued.

Is that what you want? I've got probably a dozen of Digilent's boards, and found their early boards useful, because they left off the memory, displays, etc. The more hardware they included, the less one could do with their board. In this, they're not alone.

I agree about the book from CYPRESS. It's not a dedicated-to-Cypress textbook, owing largely to the fact that CYPRESS didn't build FPGA's, though they did build and sell some very serious CPLD's. Cypress is/has been more or less out of the programmable logic business, since 2003, so this book should be available for a reasonable price. I got mine from a seminar I attended. I've already given away my spare copy.

I disagree about the usefulness of many of the "features" that actually do little more than get in the way. Since there's little documentation, essentially a half-page sheet with a picture of the board, there's no low-level documentation.

My kit came with an outdated ISEv8.1 (They're on 8.2 with SP3 by now, and I've only had the board about four months. They don't have the software working right (as well as earlier versions) yet, either.) It also contains an evaluation version of the "EDK" which I have yet to examine in detail, but which might prove interesting. It also has a "resource" CD. Sadly, this has documenation for the SPARTAN-3 evaluation kit and none for the 3E evaluation kit. Since the former has SRAM and this one has none, and there are other differences, it's a disappointment. The support CD does, in fact, have a few things on it that might prove interesting to persons working with earlier device families. There's information about CAM generation, LFSR's, suggestions regarding power distribution system design, among many other things.

It is an interesting board if one wants to implement a XILINX soft-core processor, e.g. MicroBlaze, or PicoBlaze though, as I've said, it seems this particular FPGA is too limited to implement all the hardware on the board concurrently, though one might actually want to do that with this board, since it has sufficient ROM and RAM to boot and run LINUX on the MicroBlaze, and enough hardware to make it genuinely useful.

For general purpose hardware development, or for development of small MCU's, I'd leave it alone.

RE