Spartan-3E or Generic FPGA - PC133 interface details??

Question

Hi, recently I've started using FPGAs for all sorts of things, and currently I'm working on a couple designs that would benefit from a PC133 interface. I'll be putting it all on a rather tiny PCB with a Spartan-3E and a laptop-form-factor RAM socket, so the traces will be short. However, I am completely self-taught and after some newsgroup/google surfing, it seems I may need series resistors or some such things?? (I don't quite understand all this business about trace impedance, I started learning on 8-bit 20MHz MCUs and before that I was a software-only person :| )

Could anyone explain these things to me or point me to some good online explanations?

Thanks in advance!

-Eric Agan

Matthew Hicks · Accepted Answer

Because you worked at such slow speeds before you probably have never had to care about trace impedance or termination. As you use higher speed communication standards (ones with fast edge rates), you will need to master signal integrity. It might not be a huge problem with your current needs as PC133 SDR shouldn't be that bad. But, I would suggest you read some of the signal integrity articles on the Xilinx site and get a few of Howard Johnson's books on signal integrity. I would also recommend a good PCB design suite that includes a simulation program. I use Hyperlynx from Mentor Graphics.

---Matthew Hicks

PeteS · Answer

I strongly suggest you try and master some transmission line theory (in which signal integrity is based).

There are some excellent resources available on the web, but you might need some guidance. For that reason, I have x-posted this to s.e.d.

Cheers

PeteS

Spartan-3E or Generic FPGA -> PC133 interface details??

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