[sdiy] FPGA Synth Music

[Jason Tribbeck]

Hi,

> That's pretty cool!
> 
> If you were to use the newer Spartan3A parts in a VQ100 package you can
> eliminate one of the voltage regulators. Downside is that the largest
> part in that package is a 200 so it's a bit smaller than the 500 you can
> get in the 3E family. Still, the 200A size has plenty of resources (more
> mults & brams than the 250E).

Ta!

I did look at the 3A while designing it, but there was something in the datasheets about its power requirements using two supplies that I was unsure about - however, I can't remember what it was, but I think it was something to do with configuration.

The synth I'm developing on it uses around 650 slices and 4 BRAMs per "unit" (each unit has 96 quad-phase modulated oscillators each with their own 7-point FIR filter), and the 250E would just take 3 units (due to BRAM limitations).

The 200A would have more BRAM/mults available, but would probably run out of slices. However, I could take the FIR logic through mults instead of slices (which I'd have some spare), which would help. The FIR uses two mults, so having 6 per unit would mean a total of 18 BRAM/mults for 3 units - too many - so shifting only one of the FIR's mults would give 15 mults (enough), and possibly under 600 (would need to be <597) slices...

Decisions, decisions...
-- 
Jason Tribbeck