I might have said otherwise before, but these pins should probably be connected.
Datasheet does not say that analog supply is required, but recommends to connect it:
VDDA is the external analog power supply for A/D converters, D/A converters, voltage reference buffer, operational amplifiers and comparators. The VDDA voltage level is independent from the VDD voltage and should preferably be connected to VDD when these peripherals are not used.
VDDA to +3.3V
VSSA to GND
And 100nF capacitor between VDDA and VSSA pins.
I might have said otherwise before, but these pins should probably be connected.
Datasheet does not say that analog supply is required, but recommends to connect it:
VDDA to +3.3V VSSA to GND And 100nF capacitor between VDDA and VSSA pins.