Connection Issue ESP32-C6 and SSD1306 OLED Display

[modhdhruv]

Board

ESP32 C6

Device Description

Hello,

Please guide me on, How to connect SSD1306 OLED Display with ESP32 C6 Controller?

■ ESP32-C6 + OLED SSD1306 I²C Connection Issue

1. Hardware in Use

• Microcontroller: ESP32-C6 DevKitC-1
• Display: 0.96" OLED Module (I²C, SSD1306, 128×64, 3.3V)
• Pins Used:
• SDA → GPIO 6 (LP_I2C_SDA)
• SCL → GPIO 7 (LP_I2C_SCL)
• VCC → 3.3V
• GND → GND

2. The Problem

• The OLED does not respond on the I²C bus.
• The serial monitor repeatedly shows:
  ■ No I2C devices found
  E (xxxx) i2c.master: I2C transaction unexpected NACK detected
• I²C scanners detect no devices at 0x3C or 0x3D, even though the OLED should use one of these.
• The OLED module has a 472 resistor (≈4.7kΩ), which may be a pull-up or address selector.

Hardware Configuration

• SDA → GPIO 6 (LP_I2C_SDA)
• SCL → GPIO 7 (LP_I2C_SCL)
• VCC → 3.3V
• GND → GND

Version

latest stable Release (if not listed below)

Type

Task

IDE Name

Arduino IDE

Operating System

Windows 11 Pro

Flash frequency

80 MHz

PSRAM enabled

yes

Upload speed

115200

Description

Connection issue

Sketch

#include <Wire.h>
#define SDA_PIN 6 // ESP32-C6 LP_I2C_SDA
#define SCL_PIN 7 // ESP32-C6 LP_I2C_SCL
void setup() {
 Serial.begin(115200);
 delay(2000);
 Serial.println("\n■ ESP32-C6 I2C Scanner (SDA=5, SCL=6)");
 Wire.begin(SDA_PIN, SCL_PIN, 100000); // 100kHz
}
void loop() {
 byte error, address;
 int nDevices = 0;
 Serial.println("Scanning...");
 for (address = 1; address < 127; address++) {
 Wire.beginTransmission(address);
 error = Wire.endTransmission();
 if (error == 0) {
 Serial.print("■ I2C device found at 0x");
 if (address < 16) Serial.print("0");
 Serial.println(address, HEX);
 nDevices++;
 }
 else if (error == 4) {
 Serial.print("■ Unknown error at 0x");
 if (address < 16) Serial.print("0");
 Serial.println(address, HEX);
 }
 }
 if (nDevices == 0)
 Serial.println("■ No I2C devices found\n");
 delay(2000);
}

Debug Message

No I2C devices found

Other Steps to Reproduce

No response

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

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

[me-no-dev]

no issue on my end. I am guessing something with connection or screen is not OK (I do have one that failed after some use and can no longer connect to any board)

[modhdhruv]

@me-no-dev Thanks for your replay.
Can you please let me know which oled display you are using?

I have used GPIO 6 to SDA and GPIO 7 to SCL.

[me-no-dev]

SSD1306 is the oled. IOs do no matter

[modhdhruv]

Can you please let me know what connection you are using?

[lbernstone]

Those pins should work fine. If you have very long wires (ie meters) to the oled you may need to put 4.7K pull-up resistors on the signal lines.

https://wokwi.com/projects/441907690039597057

[modhdhruv]

@lbernstone Thanks for your demo Wokwi explanation.

Yesterday I tried, but it didn’t work for me.
I was able to run the SSD1306 OLED with a NodeMCU ESP8266, but I’m having issues getting it to work on the ESP32-C6 M Dev controller.

Since the OLED works fine with the ESP8266, the display and wiring are not the problem, it seems to be a connection issue specifically between the ESP32-C6 and the OLED.

Have you been able to successfully connect the SSD1306 to the ESP32-C6 using the Wokwi code and wiring you described?

Thanks

[lbernstone]

Yes. Works exactly the same in silicon and emulation. Try other pins. Perhaps 6/7 are not soldered well.

[GHVSCAR]

If you have not already solved it, why did you use these lp pins? The "normal" pins for i2c are gpio 22 and 23.