[sdiy] More Xilinx 3E board comments

[Paul Maddox]

Magnus,

> But really, the phase-accumulator should be quick and the filter should be
> slightly more work but should also work.

For the people who want a 'module', here's one I made earlier ;-
http://www.fpga.synth.net/modules/osc_core_1.shtml

It was designed to interface with an 8bit micro controlling the pitch, but 
could be modified without much effort.
I'm not sure if this would run on the newer devices, but as it's in pretty 
much 'straight' VHDL, it should be easy to make any changes (probably only 
library names).

I've also commented it and used long 'variable' names so things *should* be 
relativly obvious to the eye when reading it.

Paul