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

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...