FPGA recommendations

Look at Xilinx. They seem to be agressively pursuing your (our) market. You can download the software, IIRC the limitations don't kick in until you hit the really big expensive parts. The Mentor ModelSim requires a node-locked license, but it's free as well (and I think Xilinx is working on their own simulation package). Apparently the Mentor s/w deliberately runs slower than the $$ package, though, once you exceed 10,000 lines of code).

Also, at least according to my FAE, they deliberately don't go overboard on protecting their 'evaluation' software (you can de/re-install to get another 'evaluation', he says) because they want to sell silicon. They have soft processor cores available (8-bit is free in object code) and some of their huge 90nm arrays have a handful of PowerPCs littering the corners of the chip in case you need a processor.

I've found the S/W pretty much bug-free (perhaps not quirk-free) so far, though it will tax the speed of the best computer you can buy. I have not used Altera's software, so I can't compare.

Best regards, Spehro Pefhany

The Xilinx free Webpack software is not node locked, only Modelsim, and it doesn't 'call home'. I think it's permanent, but I've not verified this. The stuff I downloaded a couple of years ago still worked a few weeks ago, even Modelsim.

That was my conclusion.

My FAE said that the best Xilinx deal was typically with the latest silicon.

They seem to be following certain aspects of Microchip's business model-- leaving higher prices on old silicon, inexpensive development tools widely distributed, etc. Of course FPGAs use close to state-of-the art silicon processes so they can't go with surplus memory fabs for production-- they are fabless. Don't know much about Altera. Similar?

Best regards, Spehro Pefhany

Altera is similar, except that they already have simulation software (and have had for a long while, I believe). I've never bothered with the free ModelSim for Altera Quartus.

All major FPGA/CPLD players use node-locking on their tools, and all (that I know of) have some sort of time limitation on their free versions. Altera paid-for licenses are permanent - I'd guess the same applies to Xilinx.

Altera and Xilinx are by far the biggest players in the fpga market - there are others in the CPLD line (Lattice has some nice parts). But for fpgas, you are best with A or X unless you want a more specialist part.

I haven't done more than play around with X's software, and that was a while ago. But it struck me that X tools were made from a collection of different tools bundled together, while A tools were much more integrated. This made the Altera tools more consistent - I think they are a definite selling point for Altera.

Both A and X have soft processors, available under similar terms and with similar functionalities, although I personally think the Altera soft processor is a better system. Altera have effectively dropped their hard processor core line, having concluded that in virtually all cases, you are better with either a flexible soft processor or an external processor. Xilinx PPC parts are well publicised, but are a very small market.

The main difference between A and X, however, lies in their reputation for availability. I have never had to get hold of Xilinx parts, so I can't speak from personal experience, but the appearance seems to be that when Altera announce availability of a new part, you can order it. When Xilinx announces availability of a new part, you can get samples in about a year or so. If you look at the comp.arch.fpga newsgroup, you will see regular threads complaining about availability of X parts or asking when and where they can be bought.

Of course, opinions vary wildly, and depend on many factors (your target applications, the quality of your distributors, personal experience). But either way, drop the old Flex devices and go for Cyclone II / Spartan 3 (or Stratix II / Virtex for the high end) and the latest version of the tools.

Very similar. Altera and Xilinx decisions are often based on small details or personal preferences or experience - the differences are small. I just posted so that the OP wouldn't think there was something special about Xilinx parts or tools, and to give some balance.

IME, Xilinx has better I/O. Of course, they bought and killed the company who's part I was using, for their I/O IP. The project was scrapped and I had to do a complete redesign with 'X'. A year and a complete board design gone, poof. I took another year to get Virtex-E parts (with the I/O I needed).

The Altera-Xilinx decision might well come down to support. In Oz, MEMEC have provided truly excellent support for Xilinx over the years, while my experience with Altera has been quite negative - couldn't even get price/availability, let alone support. Of course, MEMEC have now been purchased by AVNET, so it remains to be seen if the support continues.