Just remembered something about the jitter...
If I commented the ADCIN command from the internal loop and just relied on the initial ADCIN read at the start of the program, the variable adjustment wouldn't work of course but be fixed at the pot setting instead and would get a clean output signal.
I read through the ADC section of the data specs that specified Rs be less than 10K, my pot is 5K and left me thinking the sampling time has to be set correctly.
Am I getting close or still wandering in the dark with a LED on a 2V battery?