Function esp_idf_svc::hal::sys::adc2_config_channel_atten

pub unsafe extern "C" fn adc2_config_channel_atten(
    channel: u32,
    atten: u32,
) -> i32

@brief Configure the ADC2 channel, including setting attenuation.

The default ADC voltage is for attenuation 0 dB and listed in the table below. By setting higher attenuation it is possible to read higher voltages.

Due to ADC characteristics, most accurate results are obtained within the “suggested range” shown in the following table.

+----------+-------------+-----------------+
|          | attenuation | suggested range |
|    SoC   |     (dB)    |      (mV)       |
+==========+=============+=================+
|          |       0     |    100 ~  950   |
|          +-------------+-----------------+
|          |       2.5   |    100 ~ 1250   |
|   ESP32  +-------------+-----------------+
|          |       6     |    150 ~ 1750   |
|          +-------------+-----------------+
|          |      11     |    150 ~ 2450   |
+----------+-------------+-----------------+
|          |       0     |      0 ~  750   |
|          +-------------+-----------------+
|          |       2.5   |      0 ~ 1050   |
| ESP32-S2 +-------------+-----------------+
|          |       6     |      0 ~ 1300   |
|          +-------------+-----------------+
|          |      11     |      0 ~ 2500   |
+----------+-------------+-----------------+

For maximum accuracy, use the ADC calibration APIs and measure voltages within these recommended ranges.

@note This function also configures the input GPIO pin mux to connect it to the ADC2 channel. It must be called before calling adc2_get_raw() for this channel.

@note For any given channel, this function must be called before the first time adc2_get_raw() is called for that channel.

@param channel ADC2 channel to configure @param atten Attenuation level

@return - ESP_OK success - ESP_ERR_INVALID_ARG Parameter error