ESP32 wont detect any i2c ports

dsfdgtreytwrfewsfaa · March 4, 2025, 10:41pm

Helloy everyone, could anyone help me with i2c? I want to connect a LCD display to my esp32, i used gpio8 as SDA and gpio9 as SCL, i have used multiple I2C scanners but none of them can find my lcd display. Anyone have a clue?
My exact ESP32 model is esp32-s3-wroom1, the latest i2c scanner i used was this one

#include <Wire.h>
  
void setup() {
  Wire.begin(8,9);
 
  Serial.begin(115200);
  while (!Serial);             // Leonardo: wait for serial monitor
  Serial.println("\nI2C Scanner");
}
 
 
void loop() {
  byte error, address;
  int nDevices;
 
  Serial.println("Scanning...");
 
  nDevices = 0;
  for(address = 1; address < 127; address++ ) {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
 
    if (error == 0) {
      Serial.print("I2C device found at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");
 
      nDevices++;
    }
    else if (error==4) {
      Serial.print("Unknown error at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.println(address,HEX);
    }    
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");
 
  delay(5000);           // wait 5 seconds for next scan
}

van_der_decken · March 4, 2025, 10:50pm

It is not obvious from your picture where your various wires are connected.

horace · March 5, 2025, 6:48am

using a ESP32-S3-DevKitC-1 connected a SSD1306 display to I2C
running the I2Cscanner code from post 1 I get

I2C Scanner
Scanning...
I2C device found at address 0x3C  !
done

running the following ClockDemo code

// library https://github.com/LilyGO/ESP32-OLED0.96-ssd1306

/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 by Daniel Eichhorn
 * Copyright (c) 2016 by Fabrice Weinberg
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */

#include <TimeLib.h>

// Include the correct display library
// For a connection via I2C using Wire include
#include <Wire.h>  // Only needed for Arduino 1.6.5 and earlier
#include "SSD1306.h" // alias for `#include "SSD1306Wire.h"`
// or #include "SH1106.h" alis for `#include "SH1106Wire.h"`
// For a connection via I2C using brzo_i2c (must be installed) include
// #include <brzo_i2c.h> // Only needed for Arduino 1.6.5 and earlier
// #include "SSD1306Brzo.h"
// #include "SH1106Brzo.h"
// For a connection via SPI include
// #include <SPI.h> // Only needed for Arduino 1.6.5 and earlier
// #include "SSD1306Spi.h"
// #include "SH1106SPi.h"

// Include the UI lib
#include "OLEDDisplayUi.h"

// Include custom images
#include "images.h"

// Use the corresponding display class:

// Initialize the OLED display using SPI
// D5 -> CLK
// D7 -> MOSI (DOUT)
// D0 -> RES
// D2 -> DC
// D8 -> CS
// SSD1306Spi        display(D0, D2, D8);
// or
// SH1106Spi         display(D0, D2);

// Initialize the OLED display using brzo_i2c
// D3 -> SDA
// D5 -> SCL
// SSD1306Brzo display(0x3c, D3, D5);
// or
// SH1106Brzo  display(0x3c, D3, D5);

// Initialize the OLED display using Wire library
//SSD1306  display(0x3c,5, 4);//, D1, D2);
SSD1306  display(0x3c,8,9);//, D1, D2);
// SH1106 display(0x3c, D3, D5);

OLEDDisplayUi ui ( &display );

int screenW = 128;
int screenH = 64;
int clockCenterX = screenW/2;
int clockCenterY = ((screenH-16)/2)+16;   // top yellow part is 16 px height
int clockRadius = 23;

// utility function for digital clock display: prints leading 0
String twoDigits(int digits){
  if(digits < 10) {
    String i = '0'+String(digits);
    return i;
  }
  else {
    return String(digits);
  }
}

void clockOverlay(OLEDDisplay *display, OLEDDisplayUiState* state) {

}

void analogClockFrame(OLEDDisplay *display, OLEDDisplayUiState* state, int16_t x, int16_t y) {
//  ui.disableIndicator();

  // Draw the clock face
//  display->drawCircle(clockCenterX + x, clockCenterY + y, clockRadius);
  display->drawCircle(clockCenterX + x, clockCenterY + y, 2);
  //
  //hour ticks
  for( int z=0; z < 360;z= z + 30 ){
  //Begin at 0° and stop at 360°
    float angle = z ;
    angle = ( angle / 57.29577951 ) ; //Convert degrees to radians
    int x2 = ( clockCenterX + ( sin(angle) * clockRadius ) );
    int y2 = ( clockCenterY - ( cos(angle) * clockRadius ) );
    int x3 = ( clockCenterX + ( sin(angle) * ( clockRadius - ( clockRadius / 8 ) ) ) );
    int y3 = ( clockCenterY - ( cos(angle) * ( clockRadius - ( clockRadius / 8 ) ) ) );
    display->drawLine( x2 + x , y2 + y , x3 + x , y3 + y);
  }

  // display second hand
  float angle = second() * 6 ;
  angle = ( angle / 57.29577951 ) ; //Convert degrees to radians
  int x3 = ( clockCenterX + ( sin(angle) * ( clockRadius - ( clockRadius / 5 ) ) ) );
  int y3 = ( clockCenterY - ( cos(angle) * ( clockRadius - ( clockRadius / 5 ) ) ) );
  display->drawLine( clockCenterX + x , clockCenterY + y , x3 + x , y3 + y);
  //
  // display minute hand
  angle = minute() * 6 ;
  angle = ( angle / 57.29577951 ) ; //Convert degrees to radians
  x3 = ( clockCenterX + ( sin(angle) * ( clockRadius - ( clockRadius / 4 ) ) ) );
  y3 = ( clockCenterY - ( cos(angle) * ( clockRadius - ( clockRadius / 4 ) ) ) );
  display->drawLine( clockCenterX + x , clockCenterY + y , x3 + x , y3 + y);
  //
  // display hour hand
  angle = hour() * 30 + int( ( minute() / 12 ) * 6 )   ;
  angle = ( angle / 57.29577951 ) ; //Convert degrees to radians
  x3 = ( clockCenterX + ( sin(angle) * ( clockRadius - ( clockRadius / 2 ) ) ) );
  y3 = ( clockCenterY - ( cos(angle) * ( clockRadius - ( clockRadius / 2 ) ) ) );
  display->drawLine( clockCenterX + x , clockCenterY + y , x3 + x , y3 + y);
}

void digitalClockFrame(OLEDDisplay *display, OLEDDisplayUiState* state, int16_t x, int16_t y) {
  String timenow = String(hour())+":"+twoDigits(minute())+":"+twoDigits(second());
  display->setTextAlignment(TEXT_ALIGN_CENTER);
  display->setFont(ArialMT_Plain_24);
  display->drawString(clockCenterX + x , clockCenterY + y, timenow );
}

// This array keeps function pointers to all frames
// frames are the single views that slide in
FrameCallback frames[] = { analogClockFrame, digitalClockFrame };

// how many frames are there?
int frameCount = 2;

// Overlays are statically drawn on top of a frame eg. a clock
OverlayCallback overlays[] = { clockOverlay };
int overlaysCount = 1;

void setup() {
  Serial.begin(115200);
  Serial.println();

	// The ESP is capable of rendering 60fps in 80Mhz mode
	// but that won't give you much time for anything else
	// run it in 160Mhz mode or just set it to 30 fps
  ui.setTargetFPS(60);

	// Customize the active and inactive symbol
  ui.setActiveSymbol((const uint8_t*)activeSymbol);
  ui.setInactiveSymbol((const uint8_t*)inactiveSymbol);

  // You can change this to
  // TOP, LEFT, BOTTOM, RIGHT
  ui.setIndicatorPosition(TOP);

  // Defines where the first frame is located in the bar.
  ui.setIndicatorDirection(LEFT_RIGHT);

  // You can change the transition that is used
  // SLIDE_LEFT, SLIDE_RIGHT, SLIDE_UP, SLIDE_DOWN
  ui.setFrameAnimation(SLIDE_LEFT);

  // Add frames
  ui.setFrames(frames, frameCount);

  // Add overlays
  ui.setOverlays(overlays, overlaysCount);

  // Initialising the UI will init the display too.
  ui.init();

  display.flipScreenVertically();

  unsigned long secsSinceStart = millis();
  // Unix time starts on Jan 1 1970. In seconds, that's 2208988800:
  const unsigned long seventyYears = 2208988800UL;
  // subtract seventy years:
  unsigned long epoch = secsSinceStart - seventyYears * SECS_PER_HOUR;
  setTime(epoch);

}


void loop() {
  int remainingTimeBudget = ui.update();

  if (remainingTimeBudget > 0) {
    // You can do some work here
    // Don't do stuff if you are below your
    // time budget.
    delay(remainingTimeBudget);

  }


}

with images.h file (in same directory as above .ino file)

const char activeSymbol[] PROGMEM = {
    B00000000,
    B00000000,
    B00011000,
    B00100100,
    B01000010,
    B01000010,
    B00100100,
    B00011000
};

const char inactiveSymbol[] PROGMEM = {
    B00000000,
    B00000000,
    B00000000,
    B00000000,
    B00011000,
    B00011000,
    B00000000,
    B00000000
};

displays

dsfdgtreytwrfewsfaa · March 5, 2025, 10:50am

I don't get why that would really matter? "i used gpio8 as SDA and gpio9 as SCL"

van_der_decken · March 5, 2025, 8:25pm

I could not tell from your picture if what you'd said you'd done matched what you'd actually done. That's why it mattered. But it no longer does. Good-bye.

dsfdgtreytwrfewsfaa · March 5, 2025, 8:35pm

errr ok

gilshultz · March 6, 2025, 1:29am

I think I know what the problem is but not from your picture, it does not give the information needed to answer your question. Post an annotated schematic showing exactly how you connected everything, be sure to show all power sources, grounds, and note any leads over 10"/25cm. Without this information you are on your own. You already lost a very knowledgeable @van_der_decken because you know better what we need then we do.

Topic		Replies	Views
I'm Stuck - ESP32-S3-DevKitC-1 No I2C Communications Science and Measurement	16	8687	December 8, 2024
My ESP32 wont detect the I2C LCD module (SOLVED) Networking, Protocols, and Devices	56	2980	September 2, 2025
ESP32 S3 I2C not working Sensors	23	6729	July 30, 2024
No I2C Devices found. Temperamental General Guidance	19	491	December 11, 2025
ESP32 Cannot find I2C devices Programming	3	196	March 13, 2026

ESP32 wont detect any i2c ports

Related topics