analogReadMilliVolts returns the wrong value in esp32-s2

[yangminglong]

Board

none

Device Description

esp32-s2

Hardware Configuration

none

Version

latest master

IDE Name

none

Operating System

none

Flash frequency

none

PSRAM enabled

no

Upload speed

none

Description

[esp32-s2-adc api-reference:]
(https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/api-reference/peripherals/adc.html)

Attenuation Measurable input voltage range
ADC_ATTEN_DB_0 0 mV ~ 750 mV
ADC_ATTEN_DB_2_5 0 mV ~ 1050 mV
ADC_ATTEN_DB_6 0 mV ~ 1300 mV
ADC_ATTEN_DB_11 0 mV ~ 2500 mV

arduino-esp32-master code at line 251:

    uint16_t adc_reading = __analogRead(pin);
    uint16_t max_reading = 8191;
    uint16_t max_mv = 1100;
    switch(__analogAttenuation){
        case 3: max_mv = 3900; break;
        case 2: max_mv = 2200; break;
        case 1: max_mv = 1500; break;
        default: break;
    }
    return (adc_reading * max_mv) / max_reading;

#4941
#4386

Sketch

none

Debug Message

none

Other Steps to Reproduce

none

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[Jason2866]

#5502 is related. Hardware calibration is not used.

[VojtechBartoska]

Thanks @Jason2866 for linking a relation. @yangminglong Is it okay to move to mentioned issue above. If yes, this issue will be closed as duplicate. Thank you for contributing and your answer.

[VojtechBartoska]

Closing as duplicate.