[sdiy] FPGA based synthesizer progress report....

[Jim Patchell]

Last night I got the Midi interface hardware working.  Not an easy thing 
to do.  I was getting a bunch of gibberish out of the Midi port...and I 
was really scratching my head...

Turns out, my Oberhiem XK was going NUTs!  It was spitting out all kinds 
of wierd stuff.  A power cycle on the XK solved that problem and it 
turned out the Midi uart worked as advertised.

Tonight...I need to get the Midi Parser working...I wrote one a long 
time ago that was compiled with Image Craft ICC, and I need to make a 
few minor changes so it will work with WinAVR gcc and also with the real 
time operating system I wrote...

Then, I need to write a scheduler to route the notes played to the 
proper set of oscillators and complete a patch editor, and it should be 
pretty much done...(well, this phase...then I need to add a digital filter).

This project has been fun.

One interesting thing I have noted.

The phase relationship of two sawtooth waveforms (even when they are 
exactly the same frequency) makes a huge difference in the timbre you 
get.  I am going to have to add (later) a feature to make sure that the 
phase of the oscillators is known at the start of a note so that the 
sound is predictable.  This also means by adding phase modulation, I 
should be able to get some interesting (but subtle) effects.
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