How to Use 2.42 Inch Small OLED Display I2C Interface 128*64 Resolution With 4pin: Examples, Pinouts, and Specs

The CH240L004A-PW by Shenzhen ChengHao Optoelectronic Co., Ltd. is a compact OLED display module with a resolution of 128x64 pixels. It utilizes an I2C interface, making it easy to integrate with microcontrollers and development boards like the Arduino UNO. The display is energy-efficient, offers high contrast, and provides excellent readability, even in low-light conditions. Its 4-pin connection simplifies wiring and reduces the risk of errors during setup.

• Wearable devices
• IoT projects and smart home systems
• Portable electronics
• Industrial control panels
• Educational and prototyping projects

1. Wiring the Display:

   • Connect the GND pin of the display to the ground (GND) of your microcontroller.
   • Connect the VCC pin to the 3.3V or 5V power supply of your microcontroller.
   • Connect the SCL pin to the I2C clock line (e.g., A5 on Arduino UNO).
   • Connect the SDA pin to the I2C data line (e.g., A4 on Arduino UNO).

2. Install Required Libraries:

   • For Arduino, install the Adafruit_GFX and Adafruit_SSD1306 libraries via the Arduino Library Manager.

3. Upload Example Code: Use the following example code to display text on the OLED:

   // Include necessary libraries
   #include <Wire.h>
   #include <Adafruit_GFX.h>
   #include <Adafruit_SSD1306.h>
   
   // Define OLED display width and height
   #define SCREEN_WIDTH 128
   #define SCREEN_HEIGHT 64
   
   // Create an SSD1306 display object with I2C address 0x3C
   #define OLED_RESET -1
   Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
   
   void setup() {
     // Initialize the display
     if (!display.begin(SSD1306_I2C_ADDRESS, 0x3C)) {
       Serial.println(F("SSD1306 allocation failed"));
       for (;;); // Halt execution if initialization fails
     }
   
     // Clear the display buffer
     display.clearDisplay();
   
     // Set text size and color
     display.setTextSize(1); // Small text size
     display.setTextColor(SSD1306_WHITE);
   
     // Display a message
     display.setCursor(0, 0); // Set cursor to top-left corner
     display.println(F("Hello, OLED!"));
     display.display(); // Render the text on the screen
   }
   
   void loop() {
     // Nothing to do here
   }
   

• Ensure the I2C address of the display (default: 0x3C) matches the address in your code.
• Use pull-up resistors (typically 4.7kΩ) on the SCL and SDA lines if your microcontroller does not have internal pull-ups.
• Avoid exceeding the operating voltage range (3.3V - 5V) to prevent damage to the display.
• Handle the display carefully to avoid scratching or damaging the OLED screen.

1. Can I use this display with a 3.3V microcontroller?

   • Yes, the display supports both 3.3V and 5V logic levels.

2. What is the default I2C address of the display?

   • The default I2C address is 0x3C. Some variants may use 0x3D.

3. Do I need external pull-up resistors for I2C?

   • Most microcontrollers have internal pull-ups, but if you experience communication issues, add external 4.7kΩ resistors.

4. Can I use this display with platforms other than Arduino?

   • Yes, the display is compatible with platforms like Raspberry Pi, ESP32, and STM32, provided you configure the I2C interface correctly.

By following this documentation, you can easily integrate the CH240L004A-PW OLED display into your projects and enjoy its high-quality visuals and ease of use.