[sdiy] FPGA Synth Music

[Eric Brombaugh]

On Mar 2, 2010, at 1:52 AM, Jason Tribbeck wrote:

>> 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.

I'm using an XC3S200AVQ100 on my current project:

http://members.cox.net/ebrombaugh1/synth/dsPIC_fpga/index.html

It's working nicely. One of the advantages is that it's slightly cheaper than the 250E I used on the previous project. The configuration issue you may be thinking of is that there's a little parameter you need to insert into the .UCF file to let the part know that it's being given 3.3V for VCCaux. That's just so that the internal references know where to set the thresholds on some of the I/O standards. Otherwise it works transparently with only two supplies (3.3V & 1.2V).

Eric