Using G33 analogRead while connected to Wi-Fi

[dollychun]

First of all, this is my first post so please let me know if there is problem

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So I thought I'd do an analog read with the G33 pin, but it worked fine at first, but when I added the code to do the wifi communication, the G33 analog read always returned 4098.

I searched and found that using ADC2 with analogread during wifi communication always returns 4098, but the G33 pin is ADC1.

I don't know what's wrong, please help!

[felmue]

Hello @dollychun

using GPIO33 as analog input and WiFi works for me. M5Atom is connected to WiFi and I get values from 0 to 4095 from GPIO33. Care to share your code?

Thanks
Felix

[dollychun]

@felmue Heres my code

#include "M5Atom.h"
#include "WiFi.h"

int analogIn = 33;

const char* ssid       = "PatoWiFi";
const char* password   = "PatoWifi_Password";

WiFiClient client;

void setup() {
  // put your setup code here, to run once:
  M5.begin(true, false, true);
  Serial.begin(115200);
  pinMode(analogIn, INPUT);
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while(WiFi.status()!=WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.print("OK");
  Serial.print("\r\nWiFi connected\r\nIP address: ");
  Serial.println(WiFi.localIP());
  client.connect("www.someurl.com", 80);
  Serial.println("sending data to server");
  client.println("POST / HTTP/1.1");
  client.println("Host: www.someurl.com");
  client.println("User-Agent: ESP32/M5Atom");
  client.println("Accept */*");
  client.println();
  
  unsigned long timeout = millis();
  while (client.available() == 0) {
    if (millis() - timeout > 5000) {
      Serial.println(">>> Client Timeout !");
      client.stop();
    }
  }

  Serial.println("receiving from remote server");
  // not testing 'client.connected()' since we do not need to send data here
  while (client.available()) {
    char ch = static_cast<char>(client.read());
    Serial.print(ch);
  }

  // Close the connection
  Serial.println();
  Serial.println("closing connection");
  client.stop();
  
  WiFi.disconnect();
}

void loop() {
  // put your main code here, to run repeatedly:
  int val = analogRead(analogIn); // Always return 4095
  Serial.printf("AnalogRead = %d\n", val);
  delay(100);
}

[felmue]

Hello @dollychun

Hmm, I am running your code (with my WiFi credentials) on an M5Atom Matrix and reading GPIO33 is fine.

I get 0 when GPIO33 is connected to GND and 4095 when connected to +3.3V and values in between when floating as expected.

AnalogRead = 0
AnalogRead = 544
AnalogRead = 16
AnalogRead = 4095

Have you confirmed that reading GPIO33 works again if you comment out the WiFi code? Maybe adding that isn't the cause that made reading GPIO33 stop working?

Thanks
Felix

[dollychun]

@felmue said in Using G33 analogRead while connected to Wi-Fi:

Have you confirmed that reading GPIO33 works again if you comment out the WiFi code? Maybe adding that isn't the cause that made reading GPIO33 stop working?

Yes. I have confirmed that it works when I remove the Wifi code...
I will try this with another atom...