How to get VBAT and internalReference voltage?

SITCore
1

How to get VBAT and internalReference voltage? I tried the following, without success:

public class VBAT
{
    private AdcController adcController3;
    private AdcChannel vbat;
    private AdcChannel internalReferenceVoltage;
    private IntPtr enable_reg;

    public VBAT()
    {
        adcController3 = AdcController.FromName(SC20260.Adc.Controller3.Id);
        vbat = adcController3.OpenChannel(SC20260.Adc.Controller3.VBAT);
        internalReferenceVoltage = adcController3.OpenChannel(SC20260.Adc.Controller3.InternalReferenceVoltage);
        enable_reg = (IntPtr)((0x40000000U + 0x18020000 + 0x6300 + 8));
    }

    public float Voltage
    {
        get
        {                
            int enable_val = Marshal.ReadInt32(enable_reg);

            enable_val |= (1 << 24);
            Marshal.WriteInt32(enable_reg, enable_val);
            
            // The VBATEN bit of the ADCx_CCR register is used to switch to the battery voltage. As the
            // VBAT voltage could be higher than VDDA, to ensure the correct operation of the ADC, the
            // VBAT pin is internally connected to a bridge divider by 4.
            float voltage = (float)(vbat.ReadValue() * InternalReferenceVoltage / 65535.0 * 4.0);

            enable_val &= ~(1 << 24);
            Marshal.WriteInt32(enable_reg, enable_val);

            return voltage;
        }
    }

    public float InternalReferenceVoltage
    {
        get
        {
            int enable_val = Marshal.ReadInt32(enable_reg);

            enable_val |= (1 << 22);
            Marshal.WriteInt32(enable_reg, enable_val);

            float voltage = (float)(internalReferenceVoltage.ReadValue() * 3.3 / 65535.0);

            enable_val &= ~(1 << 22);
            Marshal.WriteInt32(enable_reg, enable_val);

            return voltage;
        }
    }
}

static void Main()
{   
    VBAT vBat = new VBAT();

    do
    {
        Debug.WriteLine($"InternalRefeference = {vBat.InternalReferenceVoltage:f1} V, VBAT = {vBat.Voltage:f1} V");

        Thread.Sleep(1000);
    } while (true);
}