STM32L476 Changing VRef for ADC precision

[Stm325]

Hi I want to sample low voltage signals with STM32L476 so I figured it would be a good option to reduce reference voltage and I found this part in the MCU datasheet: 

Now I am using ADC in dual mode and sampling 8 bit so it is not too precise for low voltages.

In ADC1 settings, there is a checkbox:

Is it enough to set it to shift Vref from 3.3 to 2.048 or how should I set my reference voltage to 2.048?

Also If I decide to use an external Vref can I just connect lets say 1V to Vref+ for MCU to change Vref for ADC to 1V from 3.3V.

[TDK]

> Is it enough to set it to shift Vref from 3.3 to 2.048 or how should I set my reference voltage to 2.048?

VREFBUF is enabled in the SYS tab. VREFINT is and ADC channel and is not relevant here.

> Also If I decide to use an external Vref can I just connect lets say 1V to Vref+ for MCU to change Vref for ADC to 1V from 3.3V.

No, there are limits on VREF+, see datasheet.

[Stm325]

Thank you for the quick reply. I checked the system thinking it might be under there but I cannot see VREF Buffer option. 

[TDK]

Include your full chip part number and your IOC file if you can.

[TDK]

If the VDDA pin is tied to the VREF+ pin as it is on the nucleo board, the VREFBUF is unable to be used.

[Stm325]

I am using Nucleo-L476RG. I believe VDDA pin can be tied to the VREF+ pin so that can be the problem because I created the project adding the board.