DIY Digital Synth

[Jim Patchell]

jbv wrote:

> >
> >     I agree.  I even considered using a DSP at one time, the Analog Devices SHARC
> > looked interesting, but doing the gate array trip looks like a lot more fun.
>
> Could you tell us more about programing a gate array ? Actually, I've been
> reading several data sheets, but never had the opportunity to program any
> chip (mostly because I'm a Mac user, and the adequate software runs only
> on Windows or Unix...)
>
> jbv

    Designing what goes inside of the FPGA is actually not _too_ hard.  I have done
quite a few Xilinx designs and am just starting to use Altera.  In both cases the design
can be entered either as a schematic or in some sort of HDL, or both.  If you have done
logic design in the past, the FPGA will be a breeze.  Plus, the major vendor also has
some sort of logic blocks or mega functions that will allow you to plop down a 16x16
muliplier or 24 bit adder into your design which really makes things a lot easier.  In
my opinion the hardest part of doing an FPGA design is getting the data into the part
and hooking it up.  Testing can be a bit of a drag too, since there is not way to clip a
scope probe anywhere you want in the design.  Altera and Xilinx both supply a simulator
so that you can debug the design, although the altera simulator has some limitations,
but there are ways to deal with it.

    I am still working on my design.  As soon as I am ready, I will post the schematics
and HDL files (in pdf) for all to look at.

    -Jim