DDS Update

[Terry Fox]

I have now built 3 units, and all 3 work fine!  It takes about 1 hour to
build a unit.  I probably will not build any more today.  I should have
several more done by next weekend.

Because of it's max frequency, and Hal's suggestion for a name, I plan
to call these units "Fox Blox DDS-9".  This also does DS9 one better.

I can get a few to people when they want.  The only thing I want to do
is "calibrate" the oscillator frequency for each unit.  That can
actually be done later, by the user.

I have heard from Dave Borden that he's interested.  Yes, I have a
one-page that shows the wiring hookup and LP filter (2 T50-2 cores, 2
47pf, 1 220pf caps).  I can also give out a Turbo-C program that sets
the DDS-9 to a frequency.  That's about all it does.  I also have a
program that jumps between 2 preprogrammed frequencies by reprogramming
only one of the 9832 freq registers.  I wrote it to see how fast I could
hop the unit using programming rather than the 2 freq registers.  Can
anyone say hop-hop?

On my board, I also buffer the printer port with a 74HC244, but that's
not necessary.  The unit still works if you remove power, and run the
DDS-9 from just the power from the printer port's logic!!

More later.
Terry