Spartan/SpartanXL Device Selection

Although Xilinx does sell most Spartan and SpartanXL devices still (except those in PC84 and CSxxx packages), you have to use ISE 4.1 to work with those families.

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Greg Neff VP Engineering

*Microsym* Computers Inc. snipped-for-privacy@guesswhichwordgoeshere.com

Consider shelling out the cash for a regulator (about 69 cents?) and use one of the new - read this as "inexpensive" - Xilinx devices. The functionality, capability, and support are all superior to the older devices. If you have 5V interface concerns, know that the LVTTL I/O format easily drive 5V logic and compliance with >3.3V inputs can be achieved with a series resister per Xilinx recommendations. It's such a good way to go.

Also, it can be downloaded at no cost from:

You do have to provide a design entry (synthesis) tool however as that is not included.

I also agree that it is much better to use a newer device if possible however.

-- Brian

Is it possible to interface both CMOS and TTL devices to a 3.3 V device? This is because I have to replaced a SOC on the alreay designed board and dont want to change the design too much.

74HCT series logic, for instance, is CMOS yet fully compatible with the 3.3V interface as long as the series resistors are used on the inputs (or I/Os). The 74HCT input levels are specified for TTL levels. The big question is what are the logic level requirements that you're interfacing with?

Don't expect to replace a SYSTEM on a chip with a Spartan/SpartanXL. Have you checked out the densities of those old devices?

Thanks for the help. I've decided to go for Spartan II now. saw the price difference between Spartan and Spartan II.