How to Use Display TFT 1.9": Examples, Pinouts, and Specs

The Adafruit 1.9-inch TFT Display (Part ID: ST7789) is a high-quality thin-film transistor (TFT) display designed for use in embedded systems and portable devices. It features vibrant color graphics and a compact form factor, making it ideal for applications requiring a small yet visually appealing display. The ST7789 driver chip enables efficient communication with microcontrollers, allowing for seamless integration into a variety of projects.

• Portable devices such as handheld consoles and smart gadgets
• Embedded systems requiring graphical user interfaces (GUIs)
• IoT devices for displaying sensor data or system status
• Prototyping and educational projects with microcontrollers like Arduino or Raspberry Pi

The following table outlines the key technical details of the Adafruit 1.9-inch TFT Display:

The display module has the following pinout:

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 and SDA pins to the SPI clock and data lines of your microcontroller, respectively.
3. Control Pins:
   • Connect the RES pin to a GPIO pin on your microcontroller for resetting the display.
   • Use the DC pin to differentiate between data and command signals.
   • Connect the CS pin to a GPIO pin for chip selection.
4. Backlight: Connect the BL pin to 3.3V for constant backlight or to a PWM-capable GPIO pin for brightness control.
5. Software Setup: Use a compatible library (e.g., Adafruit_GFX and Adafruit_ST7789) to initialize and control the display.

• Voltage Levels: Ensure all logic signals are at 3.3V. Use level shifters if your microcontroller operates at 5V logic.
• SPI Speed: Configure the SPI clock speed to a value supported by the ST7789 (typically up to 15 MHz).
• Reset Pin: Always initialize the display by toggling the RES pin at startup.
• Backlight Control: Use PWM to adjust the brightness of the backlight for power efficiency.

Below is an example of how to use the Adafruit 1.9-inch TFT Display with an Arduino UNO:

#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("TFT Display Test");

  // Initialize the display
  tft.init(240, 240);  // Initialize with 240x240 resolution
  tft.setRotation(1);  // Set display orientation

  // Fill the screen with a solid color
  tft.fillScreen(ST77XX_BLACK);

  // Draw a rectangle with text
  tft.fillRect(50, 50, 140, 140, ST77XX_BLUE);
  tft.setTextColor(ST77XX_WHITE);
  tft.setTextSize(2);
  tft.setCursor(60, 100);
  tft.print("Hello!");
}

void loop() {
  // Add any additional functionality here
}

1. Display Not Turning On:

   • Verify that the VCC and GND connections are correct.
   • Ensure the backlight pin (BL) is connected to 3.3V or a PWM signal.

2. No Output or Incorrect Graphics:

   • Check the SPI connections (SCL, SDA, CS, DC) for proper wiring.
   • Ensure the SPI clock speed is within the supported range of the ST7789.

3. Flickering or Dim Backlight:

   • Verify the backlight voltage is stable and within the specified range (3.0V to 3.3V).
   • If using PWM for brightness control, ensure the frequency is high enough to avoid visible flicker.

4. Reset Issues:

   • Ensure the RES pin is properly toggled during initialization.
   • Check for loose connections on the RES pin.

Q: Can I use this display with a 5V microcontroller?
A: Yes, but you must use level shifters to convert the 5V logic signals to 3.3V.

Q: What is the maximum SPI clock speed supported?
A: The ST7789 typically supports SPI clock speeds up to 15 MHz.

Q: Can I control the backlight brightness?
A: Yes, connect the BL pin to a PWM-capable GPIO pin to adjust brightness.

Q: Is this display compatible with Raspberry Pi?
A: Yes, the display can be used with Raspberry Pi using SPI and appropriate libraries.