adc2_config_channel_atten() function

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.

Syntax

Show:

Summary

Declaration

Definition

from adc.h:229

esp_err_t adc2_config_channel_atten(adc2_channel_t channel, adc_atten_t atten);

Implemented in adc_legacy.c:437

Arguments

Argument

Description

channel

ADC2 channel to configure

atten

Attenuation level

Return value

- ESP_OK success - ESP_ERR_INVALID_ARG Parameter error

Notes

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