Analog to Digital Converter Overview The ESP32 integrates two 12-bit SAR ( Successive Approximation Register ) ADCs, supporting a total of 18 measurement channels (analog enabled pins). The ADC driver API supports ADC1 (8 channels, attached to GPIOs 32 - 39), and ADC2 (10 channels, attached to GPIOs 0, 2, 4, 12 - 15 and 25 - 27). However, the usage of ADC2 has some restrictions for the application: ADC2 is used by the Wi-Fi driver. Therefore the application can only use ADC2 when the Wi-Fi driver has not started. Some of the ADC2 pins are used as strapping pins (GPIO 0, 2, 15) thus cannot be used freely. Such is the case in the following official Development Kits: ESP32 DevKitC : GPIO 0 cannot be used due to external auto program circuits. ESP-WROVER-KIT : GPIO 0, 2, 4 and 15 cannot be used due to external connections for different purposes. Configuration and Reading ADC Each ADC unit supports two work modes, ADC-RTC or ADC-DMA mode. ADC-RTC is controlled by...