pub fn enable_pin<PIN>(&mut self, pin: PIN, attenuation: Attenuation) -> AdcPin<PIN, ADCI>
    where
        PIN: AdcChannel + AnalogPin,
    {
        // TODO revert this on drop
        pin.set_analog(crate::private::Internal);
        self.attenuations[PIN::CHANNEL as usize] = Some(attenuation);

        AdcPin {
            pin,
            cal_scheme: AdcCalScheme::<()>::new_cal(attenuation),
            _phantom: PhantomData,
        }
    }
Enable the specified pin with the given attenuation
esp-hal/src/analog/adc/mod.rs