Right now VREF+ is connected to AVDD, which is derived from the not-very-accurate 3.3v regulator. Adding a proper reference like the REF3033 (available at JLC!) will improve accuracy of analog readings.
The AMS1117 is rated for +-2% accuracy with no rating for temperature compensation
The REF3033 is rated for +-0.2% accuracy with 50ppm/C maximum temperature compensation
Right now VREF+ is connected to AVDD, which is derived from the not-very-accurate 3.3v regulator. Adding a proper reference like the REF3033 (available at JLC!) will improve accuracy of analog readings.
The AMS1117 is rated for +-2% accuracy with no rating for temperature compensation The REF3033 is rated for +-0.2% accuracy with 50ppm/C maximum temperature compensation