Si5351 VFO

A few years ago I made a VFO with an AD9850.  Now I changed it to be a Si5351.  I am using the same awesome setup from Jan again - he updated his for this chip.  I even still had the lcd/wires on a breadboard, so I just had to wire it back to the Arduino!

Several things I ran into:

• I had a hard time convincing it to use the right libraries.  I had some out of date versions of some, and it kept wanting to use the Adafruit library instead of the Etherkit one.  I finally deleted the Adafruit one to get it to work.  
• It didn't work at first, and I thought I had fried another Si5351.  I put another one in, and it didn't work, either.  I suspected my wiring, but then tried the Adafruit sketch I had made, and it worked.  Turns out it was the i2c address - I had to update it to be 0x60.
• The calibration was off.  It was actually off by about the same as the default BFO frequency, so I went down all sorts of rabbit holes trying to figure out why it was adding that in (which it wasn't).  Finally figured it was actually the calibration, and ran the calibration tool the Etherkit library has (which is kind of awesome) to fix it.
• I can't seem to get the Arduino to acknowledge changes I make to the 'definitions.h' file.  Or at least when I change those and reupload, they don't seem to have taken effect.  Maybe something with the eeprom, not sure.  I ended up changing the calibration in the .ino file for now while I look some more.

I had originally planned to use this with a Tayloe mixer.  But I screwed up my mouser order and the IC I got is the *smallest* I think it could possibly be.  It was one of the last things I put in that order and I was pretty tired at that point, and I swear I checked that it was larger than that...  Anyway, I decided I would try this with the EMRFD direct conversion receiver I had made a while back, but it is now pouring outside so don't want to go out in the rain to pull in then feedline.  So that is a project for another night.