ADC2 Channel cannot be used when WiFi is in use #440

bestpika · 2017-06-13T12:10:44Z

When WiFi.begin(...), I can't read all ADC2's channel.
All value is incorrect.

The text was updated successfully, but these errors were encountered:

prices · 2017-06-14T20:58:01Z

I was just tracking this. I set up a simple circuit with a pot from VCC to GND with the wiper connected to IO34 and IO25. IO34 is ADC1, IO25 is ADC2. I used the following code in the Arduino IDE v1.8.1:

#include "WiFi.h"

unsigned long previousMillis;        // will store last temp was read
uint32_t delayMS;


void setup() {
  Serial.begin(115200);
  // put your setup code here, to run once:
    pinMode(34, ANALOG);
    pinMode(25, ANALOG);
    delayMS = 1000;
    previousMillis = 0;
    WiFi.begin("test", "testpassword");  // Comment this line out and it works.

}

void loop() {
  // put your main code here, to run repeatedly:
    unsigned long currentMillis = millis();
    if (currentMillis - previousMillis >= delayMS) {
        previousMillis = currentMillis;
        Serial.print("ADC1: ");
        Serial.println(analogRead(34));
        Serial.print("ADC2: ");
        Serial.println(analogRead(25));
    }
}

Results with WiFi.begin() in the code (binary size 507808 bytes):

ADC1: 608^M$
ADC2: 4095^M$
ADC1: 610^M$
ADC2: 4095^M$
ADC1: 608^M$
ADC2: 4095^M$
ADC1: 608^M$
ADC2: 4095^M$

Results with WiFi.begin() commented out (binary size 299472 bytes):

ADC1: 609^M$
ADC2: 893^M$
ADC1: 612^M$
ADC2: 894^M$
ADC1: 612^M$
ADC2: 892^M$
ADC1: 608^M$
ADC2: 896^M$

Before testing I completely wiped the flash on the device using

esptool.py --port /dev/ttyUSB0 erase_flash

Let me know if there is any more information you need.

prices · 2017-06-15T21:10:35Z

I found some information here:

#102

The comment is from igrr saying:
"This happens because ADC2 pins can not be used when WiFi is used."

I have yet to find confirmation of this in the data sheets, but I am still looking.

prices · 2017-06-16T13:24:46Z

Seems now I have confirmation that this is not a software bug. It is the chip itself. This will not get fixed in software.

prices · 2017-06-16T13:50:58Z

It seems that ADC2 is used with WiFi and maybe BlueTooth. That is why it is unavailable. So this might be fixed, but won't be fixed in this software. It will get fixed in the SDK.

https://www.esp32.com/viewtopic.php?t=1822#p10097

copercini · 2017-09-29T14:28:34Z

Let's concentrate ADC2 conflict with wifi here: #440
to keep the things organized =)

prices · 2017-09-29T14:50:32Z

I am just curious that you said we should concentrate the discussion in this bug, then closed this bug. Did you mean to point to a different bug?

copercini · 2017-09-29T14:55:43Z

Oh, I linked the wrong issue, this is the correct one (which I think is the same discussion): #102
Sorry =)

danielcolchete · 2019-02-23T22:25:46Z

For the record, resetting registers SENS_SAR_START_FORCE_REG and SENS_SAR_READ_CTRL2_REG to the old values they had before WiFi was turned seem to be a work around for this issue. And will allow you to use ADC2 again after you stop and deinitialize WiFI.

An algorithm here would be something like:
old1 <- SENS_SAR_START_FORCE_REG
old2 <- SENS_SAR_READ_CTRL2_REG
InitWifi
StartWifiAndConnect
(Do your wifi thing here)
StopWifiAndDisconnect
DeinitWifi
SENS_SAR_START_FORCE_REG <- old1
SENS_SAR_READ_CTRL2_REG <- old1

danielcolchete · 2019-02-23T22:35:51Z

I forgot to include the SENS_SAR_MEAS_START2_REG register. This one is important too.

Hetric · 2019-03-08T21:01:19Z

I forgot to include the SENS_SAR_MEAS_START2_REG register. This one is important too.

@danielcolchete, do you have the Arduino code to fix the ADC2 problem by any chance? I'm trying to use Bluetooth to send analog values from ADC2. I have no luck so far.

grasmanek94 · 2020-05-06T21:53:19Z

ADC2 cannot be used with WiFi or Bluetooth? Well this code just proves that statement wrong!

#define DR_REG_SENS_BASE 0x3ff48800
#define SENS_SAR_START_FORCE_REG (DR_REG_SENS_BASE + 0x002c)
#define SENS_SAR_READ_CTRL2_REG (DR_REG_SENS_BASE + 0x0090)
#define SENS_SAR_MEAS_START2_REG (DR_REG_SENS_BASE + 0x0094)

int pin = 27;
uint64_t reg_a;
uint64_t reg_b;
uint64_t reg_c;

void setup()
{
    reg_a = READ_PERI_REG(SENS_SAR_START_FORCE_REG);
    reg_b = READ_PERI_REG(SENS_SAR_READ_CTRL2_REG);
    reg_c = READ_PERI_REG(SENS_SAR_MEAS_START2_REG);

    Serial.begin(115200);

    btStart();

    PS4.begin("03:03:03:03:03:03");

    WRITE_PERI_REG(SENS_SAR_START_FORCE_REG, reg_a);
    WRITE_PERI_REG(SENS_SAR_READ_CTRL2_REG, reg_b);
    WRITE_PERI_REG(SENS_SAR_MEAS_START2_REG, reg_c);

    pinMode(27, INPUT);
    analogSetPinAttenuation(27, ADC_11db);
}

uint16_t fixedAnalogRead(int pin_number)
{
    WRITE_PERI_REG(SENS_SAR_START_FORCE_REG, reg_a);
    WRITE_PERI_REG(SENS_SAR_READ_CTRL2_REG, reg_b);
    WRITE_PERI_REG(SENS_SAR_MEAS_START2_REG, reg_c);
    return analogRead(pin_number);
}

void Loop()
{
    // do fixedAnalogRead and Bluetooth stuff in Loop. I managed to use my PS4 controller and ADC2 / pin27 on SBC-NodeMCU-ESP32
    if(PS4.isConnected())
    {
        Serial.printf("Connected.. ");
    }
    Serial.printf("%d\r\n", fixedAnalogRead(pin));
    delay(100);
}

When doing a varistor sweep + using a DualShock PS4 controller via bluetooth connected to my ESP32:

Connected.. 0
Connected.. 17
Connected.. 55
Connected.. 93
Connected.. 81
Connected.. 162
Connected.. 200
Connected.. 229
Connected.. 257
Connected.. 304
Connected.. 321
Connected.. 365
Connected.. 410
Connected.. 755
Connected.. 1447
Connected.. 2173
Connected.. 3009
Connected.. 4095
Connected.. 4095
Connected.. 4095
Connected.. 4095
Connected.. 4095
Connected.. 4095
Connected.. 4095
Connected.. 4095
Connected.. 3022
Connected.. 2659
Connected.. 2253
Connected.. 1521
Connected.. 742

michox · 2020-05-21T10:47:47Z

@grasmanek94 I did this your way, but it won't work. Only after removing the writing of reg_a and reg_c will I get some differing values although they are inverted and only have attenutation of 1db

grasmanek94 · 2020-05-22T10:11:36Z

In the technical reference you probably can find the registers for the inverted values (something that can be disabled) and also change the attenuation, I think. The code I posted is created from multiple snippets throughout my codebase but simplified, It's possible that I missed analogSetAttenuation (or whatever the function is called).

CarlosGS · 2021-06-21T14:04:32Z

To fix the inverted values: #102 (comment)

rrojasn17 · 2021-09-29T23:16:05Z

ESTO ME FUNCIONO!!!!!!!!!!!

Muchas gracias por los aportes.

Les cuento:

Tengo un ESP32 TTGO HIGROW, necesito leer en pin ADC 15 un sensor de humedad del suelo y enviarlo a mi plataforma IoT, obviamente necesito WiFI para eso.

Aquí mi proyecto: https://github.com/ISProjectsIoTCR/SensorSueloTTGO

Lo hice asÍ:

1-Leer sensores
2-Conectarme al Wifi
3-Desconectar Wifi
4-Ir a dormir esp_deep_sleep_start();

La primer lectura del sensor lo hacía bien, pero despues del lapso en sueño profundo, me disparaba un valor en alto de mi pin analógico. Eso pasa porque despues de usar analogRead iniciaba mi Wifi y modificaba esos registros que se mencionan en este hilo. Aun no entiendo mucho sobre esos regitros pero hice lo que pude leer aquí.

Lo mejoré asÍ:

1-Leer sensores
2-Leer registros
3-Conectarme al Wifi
4-Desconectar Wifi
5-Escribir los registros con los valores originales.
6-Ir a dormir esp_deep_sleep_start();

AL INICIO DEL CODIGO=>

#define DR_REG_SENS_BASE 0x3ff48800
#define SENS_SAR_START_FORCE_REG (DR_REG_SENS_BASE + 0x002c)
#define SENS_SAR_READ_CTRL2_REG (DR_REG_SENS_BASE + 0x0090)
#define SENS_SAR_MEAS_START2_REG (DR_REG_SENS_BASE + 0x0094)

DECLARAR VARIABLES GLOBALES "uint64" =>

uint64_t reg_a;
uint64_t reg_b;
uint64_t reg_c;

JUSTO ANTES DE INICIAR LA CONEXIÓN WIFI=>

reg_a = READ_PERI_REG(SENS_SAR_START_FORCE_REG);
reg_b = READ_PERI_REG(SENS_SAR_READ_CTRL2_REG);
reg_c = READ_PERI_REG(SENS_SAR_MEAS_START2_REG);

ANTES DE IR A DORMIR=>

WRITE_PERI_REG(SENS_SAR_START_FORCE_REG, reg_a); // fix ADC registers
WRITE_PERI_REG(SENS_SAR_READ_CTRL2_REG, reg_b);
WRITE_PERI_REG(SENS_SAR_MEAS_START2_REG, reg_c);

Y LISTO!!! FUNCIONÓ

Tobbera · 2022-01-08T22:28:10Z

I can confirm that this is working as a workaround.

// Initiate Wifi with ADC2 on ESP32 workaround bellow:
#include "soc/sens_reg.h"    // needed for manipulating ADC2 control register
uint32_t adc_register;
uint32_t wifi_register;
// End initiation of Wifi with ADC2 on ESP32 workaround.

setup:
Serial.begin(115200);
  adc_register = READ_PERI_REG(SENS_SAR_READ_CTRL2_REG); // Wifi with ADC2 on ESP32 workaround.
*** Connect WiFi / Bluetooth stuff here ***
  wifi_register = READ_PERI_REG(SENS_SAR_READ_CTRL2_REG); // Wifi with ADC2 on ESP32 workaround.

loop:
  WRITE_PERI_REG(SENS_SAR_READ_CTRL2_REG, adc_register); // Wifi with ADC2 on ESP32 workaround.
  SET_PERI_REG_MASK(SENS_SAR_READ_CTRL2_REG, SENS_SAR2_DATA_INV);// Wifi with ADC2 on ESP32 workaround.
*** Analog read stuff here***
  WRITE_PERI_REG(SENS_SAR_READ_CTRL2_REG, wifi_register); // Wifi with ADC2 on ESP32 workaround.

BUT, its broken in the newer version of ESP32 in arduino. This works on 1.0.3 at the moment. I cant understand why they took it away.

lonerzzz changed the title ~~ADC2 issue~~ ADC2 cannot be used when WiFi is in use Aug 15, 2017

lonerzzz added the Type: For reference Common questions & problems label Aug 15, 2017

lonerzzz changed the title ~~ADC2 cannot be used when WiFi is in use~~ ADC2 Channel cannot be used when WiFi is in use Aug 18, 2017

copercini closed this as completed Sep 29, 2017

beegee-tokyo mentioned this issue Dec 29, 2017

GPIO input mode with softAP #953

Closed

umartechboy mentioned this issue Jul 11, 2020

the analogRead seems doesn't work #683

Closed

luciangpl mentioned this issue Jul 30, 2021

The second ADC channel can't be used arendst/Tasmota#12783

Closed

6 tasks

RTLhamster mentioned this issue Sep 5, 2022

use ESP-now and ADC at the same time (AEGHB-36) espressif/esp-now#41

Closed

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

ADC2 Channel cannot be used when WiFi is in use #440

ADC2 Channel cannot be used when WiFi is in use #440

bestpika commented Jun 13, 2017 •

edited

Loading

prices commented Jun 14, 2017 •

edited

Loading

prices commented Jun 15, 2017

prices commented Jun 16, 2017

prices commented Jun 16, 2017

copercini commented Sep 29, 2017

prices commented Sep 29, 2017

copercini commented Sep 29, 2017

danielcolchete commented Feb 23, 2019

danielcolchete commented Feb 23, 2019

Hetric commented Mar 8, 2019

grasmanek94 commented May 6, 2020

michox commented May 21, 2020

grasmanek94 commented May 22, 2020

CarlosGS commented Jun 21, 2021

rrojasn17 commented Sep 29, 2021 •

edited

Loading

Tobbera commented Jan 8, 2022 •

edited

Loading

ADC2 Channel cannot be used when WiFi is in use #440

ADC2 Channel cannot be used when WiFi is in use #440

Comments

bestpika commented Jun 13, 2017 • edited Loading

prices commented Jun 14, 2017 • edited Loading

prices commented Jun 15, 2017

prices commented Jun 16, 2017

prices commented Jun 16, 2017

copercini commented Sep 29, 2017

prices commented Sep 29, 2017

copercini commented Sep 29, 2017

danielcolchete commented Feb 23, 2019

danielcolchete commented Feb 23, 2019

Hetric commented Mar 8, 2019

grasmanek94 commented May 6, 2020

michox commented May 21, 2020

grasmanek94 commented May 22, 2020

CarlosGS commented Jun 21, 2021

rrojasn17 commented Sep 29, 2021 • edited Loading

Tobbera commented Jan 8, 2022 • edited Loading

bestpika commented Jun 13, 2017 •

edited

Loading

prices commented Jun 14, 2017 •

edited

Loading

rrojasn17 commented Sep 29, 2021 •

edited

Loading

Tobbera commented Jan 8, 2022 •

edited

Loading