Spartan 3 or 3E ?

"Dave" schrieb im Newsbeitrag news:TZGdnVxMkOOSR4vYnZ2dnUVZ snipped-for-privacy@giganews.com...

Spartan3E is advertised as FPGA with 25% more logic ressources and 25% less cost than Spartan3. Check your distri or digikey about that.

Some hidden facts:

- Spartan3E has less I/O's than Spartan3, but has additional input only pins. If your application can use these inputs - e.g. for adc's - you have more available user pins than on S3.

- Spartan3E has fewer packaging options, e.g. the XC3S500E is not availlable in a TQ144 package. The S3 XC3S400 has a TQ144 option.

- Spartan3E has muxed configuration pins which can be advantage or disadvantage, depending on design. The spi flash support is a main advantage for system cost savings. Further on parallel memory is supported for configuration.

- Spartan3E has improved multipliers. Check a simple design with a*b (2 72 bit vectors), the logic ressources on Spartan3E are less.

There are other differences, like configuration bit stream length, etc., they should be collected, and put in the FAQ.

MIKE

Things I like about Spartan-3E V Spartan-3

Config from SPI or Flash. - Cheap and usually only needs one device.

The differential terminator.

Cost is slightly better? - Does depend on project needs which is best.

The magicbox gate to speed up PCI.

What I don't like No DCI

The number of input only pins. Why could these not have been clock pins and left us more general I/O.

There are only 4 banks of I/O that limit combinations when you have a multvoltage I/O system. For example you could have Flash at 3.3V, DDR2 at 1.8V, LVDS at 2.5V in a system. In this kind of system you can't always use the left overs on a bank on one particular voltage. Spartan-3 wins because it has 8 banks and less lossy in this situation.

The general architecture and internal speeds are essentially the same and if it were available I would love a Spartan-3 with a SPI load. Unless I am totally penny pinching then my choice would almost always be Spartan-3.

John Adair Enterpo> OK, I've read the xilinx blurb but I still don't understand the difference