Putting the finishing touches on an assignment (ESP-IDF PlatformIO) and my ADC initialization is throwing a warning that a define I'm calling is deprecated. It builds, so this is more in the "it bugs me" category: IOW it's not game-breaking but I'd still like to know how to fix it.

// main function
void app_main() {
    esp_event_loop_create_default();
    connect_wifi_params_t cbs = {
        .on_connected = handle_wifi_connect,
        .on_failed = handle_wifi_failed
    };

    // configure ADC for 12-bit width, 3.3V source
    // Photoresistor needs to be connected from 3.3V to pin 34.
    adc1_config_width(ADC_WIDTH_BIT_12);
    adc1_config_channel_atten(adc_channel, ADC_ATTEN_DB_11);
    
    // connect wifi
    appwifi_connect(cbs);
}

And the call to the ADC if it helps any.

// transmit reading to server. Photoresistor is read here.
static void publish_reading(int temp, int hum) {
    char buffer[5];
    if (client != NULL && enabled) {
        esp_mqtt_client_publish(client, TEMP_TOPIC, itoa(temp, buffer, 10), 0, 1, 0);
        esp_mqtt_client_publish(client, HUM_TOPIC, itoa(hum, buffer, 10), 0, 1, 0);
        // average ADC value over 32 samples and send it
        int adc_val = 0;
        for (unsigned char i = 0; i < SAMPLE_CNT; i++) adc_val += adc1_get_raw(adc_channel);
        adc_val /= SAMPLE_CNT;
        esp_mqtt_client_publish(client, PHOTO_TOPIC, itoa(adc_val, buffer, 10), 0, 1, 0);
    }
}

The warning says that ADC_ATTEN_DB_11 is deprecated.

ETA: I should clarify my troubleshooting steps: I already tried ADC_ATTEN_DB_12. The warning says "legacy adc driver is deprecated, please migrate to use esp_adc/adc_oneshot.h and esp_adc/adc_continuous.h for oneshot mode and continuous mode drivers respectively".

Putting the finishing touches on an assignment (ESP-IDF PlatformIO) and my ADC initialization is throwing a warning that a define I'm calling is deprecated. It builds, so this is more in the "it bugs me" category: IOW it's not game-breaking but I'd still like to know how to fix it.

// main function
void app_main() {
    esp_event_loop_create_default();
    connect_wifi_params_t cbs = {
        .on_connected = handle_wifi_connect,
        .on_failed = handle_wifi_failed
    };

    // configure ADC for 12-bit width, 3.3V source
    // Photoresistor needs to be connected from 3.3V to pin 34.
    adc1_config_width(ADC_WIDTH_BIT_12);
    adc1_config_channel_atten(adc_channel, ADC_ATTEN_DB_11);
    
    // connect wifi
    appwifi_connect(cbs);
}

And the call to the ADC if it helps any.

// transmit reading to server. Photoresistor is read here.
static void publish_reading(int temp, int hum) {
    char buffer[5];
    if (client != NULL && enabled) {
        esp_mqtt_client_publish(client, TEMP_TOPIC, itoa(temp, buffer, 10), 0, 1, 0);
        esp_mqtt_client_publish(client, HUM_TOPIC, itoa(hum, buffer, 10), 0, 1, 0);
        // average ADC value over 32 samples and send it
        int adc_val = 0;
        for (unsigned char i = 0; i < SAMPLE_CNT; i++) adc_val += adc1_get_raw(adc_channel);
        adc_val /= SAMPLE_CNT;
        esp_mqtt_client_publish(client, PHOTO_TOPIC, itoa(adc_val, buffer, 10), 0, 1, 0);
    }
}

The warning says that ADC_ATTEN_DB_11 is deprecated.

ETA: I should clarify my troubleshooting steps: I already tried ADC_ATTEN_DB_12. The warning says "legacy adc driver is deprecated, please migrate to use esp_adc/adc_oneshot.h and esp_adc/adc_continuous.h for oneshot mode and continuous mode drivers respectively".

• c
• deprecated
• adc
• esp-idf

Share Improve this question Follow edited Nov 21, 2024 at 15:10 StarSword asked Nov 21, 2024 at 2:42 StarSwordStarSword 7799 bronze badges 2

• It builds, so this is more in the "it bugs me" category — at the moment, but it is deprecated, so some day it will go away and then your code won't build. Take the time (now!) to update the code to use the replacement before it bites you. – Jonathan Leffler Commented Nov 21, 2024 at 3:52
• I've updated with the troubleshooting steps I already took: slipped my mind last night. – StarSword Commented Nov 21, 2024 at 15:12

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2 Answers 2

Sorted by: Reset to default 1

If you look in the manual at ADC Oneshot Mode Driver, if you search for ADC_ATTEN_DB, you will find:

enumerator ADC_ATTEN_DB_12
The input voltage of ADC will be attenuated extending the range of measurement by about 12 dB.

enumerator ADC_ATTEN_DB_11
This is deprecated, it behaves the same as ADC_ATTEN_DB_12

So replace ADC_ATTEN_DB_11 with ADC_ATTEN_DB_12.

After a lot of digging, I figured out how to fix it with the purportedly new-and-improved header file. Updated code:

#include "esp_adc/adc_oneshot.h"

// define
#define SAMPLE_CNT 32 // average this number of ADC samples to get reading

// global
adc_oneshot_unit_handle_t adc1_handle;


// returns the average of 32 ADC samples
static int AverageADCSamp() {
    int samples = 0;

    for (unsigned char i = 0; i < SAMPLE_CNT; i++) {
        int rawValue = 0;
        ESP_ERROR_CHECK(adc_oneshot_read(adc1_handle, ADC_CHANNEL_6, &rawValue));
        samples += rawValue;
    }
    return samples / SAMPLE_CNT; // return the average 
}

// transmit reading to server. Photoresistor is read here.
static void publish_reading(int temp, int hum) {
    char buffer[5];
    if (client != NULL && enabled) {
        esp_mqtt_client_publish(client, TEMP_TOPIC, itoa(temp, buffer, 10), 0, 1, 0);
        esp_mqtt_client_publish(client, HUM_TOPIC, itoa(hum, buffer, 10), 0, 1, 0);
        // average ADC value over 32 samples and send it
        esp_mqtt_client_publish(client, PHOTO_TOPIC, itoa(AverageADCSamp(), buffer, 10), 0, 1, 0);
    }
}

// main function
void app_main() {
    esp_event_loop_create_default();
    connect_wifi_params_t cbs = {
        .on_connected = handle_wifi_connect,
        .on_failed = handle_wifi_failed
    };

    // configure ADC for 12-bit width, 3.3V source
    // Photoresistor needs to be connected from 3.3V to pin 34.
    adc_oneshot_unit_init_cfg_t ADC1_C6_config = {
        .unit_id = ADC_UNIT_1
    };
    ESP_ERROR_CHECK(adc_oneshot_new_unit(&ADC1_C6_config, &adc1_handle));
    adc_oneshot_chan_cfg_t channel_config = {
        .bitwidth = ADC_BITWIDTH_12,
        .atten = ADC_ATTEN_DB_12
    };
    ESP_ERROR_CHECK(adc_oneshot_config_channel(adc1_handle, ADC_CHANNEL_6, &channel_config));
    
    // connect wifi
    appwifi_connect(cbs);
}