Getting started with programmable logic, was Re: Cray 1 replica

Richard wrote: The Spartan-3 (no alpha suffix) is now an "older" family (as compared to the -3E, -3A, and -6), so yes, they might only be "pushing" the automotive spec parts, but they are still in full production in the standard commercial and industrial grades. Basically to get information for older devices out of the Xilinx web site requires clicking on "all devices" or some such thing. In fact, even the older Spartan-XL and Spartan-2 families are in full production, though they are not recommended for new designs, and you have to use older ("archived") versions of the ISE software to develop for them. (For Spartan-XL, there is no version of ISE that included HDL synthesis, so I definitely recommend against trying to use those for hobbyist development with Verilog or VHDL.) Beyond that, even some of the XC3000 and XC4000 parts are still in production. AFAIK, the only FPGA families that Xilinx have completely discontinued are the original XC2000 series (introduced in 1985), XC5200 series, and XC6200 series. Generally speaking, it only makes sense to use the most recent two generations of FPGAs for new designs, as the newer parts are always more cost-effective than the older ones, thanks largely to Moore's Law. Usually the only reason not to use the very latest (currently Spartan-6) is that the availability is not as good as the previous generation (Spartan-3E, -3A). Eric