How to Use 1.54'' TFT Display 240x240 spi ST7789: Examples, Pinouts, and Specs

The 1.54-inch TFT Display is a compact and vibrant display module with a resolution of 240x240 pixels. It utilizes the ST7789 driver and communicates via the SPI (Serial Peripheral Interface) protocol, making it an excellent choice for embedded systems and small devices. This display is ideal for applications requiring a high-quality graphical interface, such as IoT devices, handheld gadgets, and wearable electronics.

• Smartwatches and fitness trackers
• IoT dashboards and control panels
• Portable gaming devices
• Embedded systems requiring graphical output
• Educational and hobbyist projects with microcontrollers like Arduino or Raspberry Pi

Below are the key technical details and pin configuration for the 1.54'' TFT Display:

1. Power Supply: Connect the VCC pin to a 3.3V power source and the GND pin to ground.
2. SPI Communication: Connect the SCL (clock) and SDA (data) pins to the corresponding SPI pins on your microcontroller.
3. Control Pins:
   • Connect the RES pin to a GPIO pin for resetting the display.
   • Use the DC pin to toggle between data and command modes.
   • Connect the CS pin to a GPIO pin to enable or disable the display.
4. Backlight: Connect the BLK pin to 3.3V for constant backlight or to a PWM pin for brightness control.

• Voltage Levels: Ensure all logic signals are at 3.3V. If using a 5V microcontroller (e.g., Arduino UNO), use level shifters to avoid damaging the display.
• SPI Speed: The ST7789 supports high SPI clock speeds, but start with a moderate speed (e.g., 4 MHz) to ensure stable communication.
• Initialization: The display requires proper initialization commands to function. Use a compatible library (e.g., Adafruit_GFX or TFT_eSPI) to simplify this process.
• Backlight Control: If you want to control the backlight brightness, use a PWM signal on the BLK pin.

Below is an example of how to use the 1.54'' TFT Display with an Arduino UNO using the Adafruit_GFX and Adafruit_ST7789 libraries:

#include <Adafruit_GFX.h>      // Core graphics library
#include <Adafruit_ST7789.h>   // ST7789 driver library
#include <SPI.h>               // SPI library

// Define pin connections
#define TFT_CS    10  // Chip Select pin
#define TFT_RST   9   // Reset pin
#define TFT_DC    8   // Data/Command pin

// Initialize the display object
Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST);

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(9600);
  Serial.println("Initializing display...");

  // Initialize the display
  tft.init(240, 240);  // Initialize with 240x240 resolution
  tft.setRotation(1);  // Set display rotation (0-3)

  // Fill the screen with a color
  tft.fillScreen(ST77XX_BLACK);
  tft.setTextColor(ST77XX_WHITE);
  tft.setTextSize(2);
  tft.setCursor(10, 10);
  tft.println("Hello, World!");
}

void loop() {
  // Example: Draw a red rectangle
  tft.fillRect(50, 50, 100, 100, ST77XX_RED);
  delay(1000);

  // Example: Clear the rectangle
  tft.fillRect(50, 50, 100, 100, ST77XX_BLACK);
  delay(1000);
}

• Install the Adafruit_GFX and Adafruit_ST7789 libraries via the Arduino Library Manager.
• Use appropriate level shifters if connecting to a 5V microcontroller.

1. Display Not Turning On:

   • Verify the power connections (VCC and GND).
   • Ensure the BLK pin is connected to 3.3V or a PWM signal.

2. No Output on the Screen:

   • Check the SPI connections (SCL, SDA, CS, DC).
   • Ensure the RES pin is properly connected and initialized in the code.
   • Verify that the initialization sequence in the code matches the ST7789 requirements.

3. Flickering or Unstable Display:

   • Reduce the SPI clock speed in the code.
   • Ensure proper grounding and minimize noise in the circuit.

4. Incorrect Colors or Artifacts:

   • Verify the color format (16-bit RGB) used in the code.
   • Check for loose or incorrect connections.

Q: Can I use this display with a Raspberry Pi?
A: Yes, the display is compatible with Raspberry Pi. Use libraries like luma.lcd or Pillow for Python-based development.

Q: What is the maximum SPI clock speed supported?
A: The ST7789 can support SPI clock speeds up to 15 MHz, but start with lower speeds for stability.

Q: Can I power the display with 5V?
A: No, the display operates at 3.3V. Use a voltage regulator or level shifters if working with a 5V system.

Q: How do I control the backlight brightness?
A: Connect the BLK pin to a PWM-capable GPIO pin and adjust the duty cycle to control brightness.

This concludes the documentation for the 1.54'' TFT Display 240x240 SPI ST7789.