How to Use TFT LCD Display ST7735S: Examples, Pinouts, and Specs

The TFT LCD Display ST7735S is a compact and versatile display module that utilizes a thin-film-transistor liquid-crystal display (TFT LCD) technology for rich color graphics. This display is controlled by the ST7735S, a single-chip controller/driver that provides a high-quality GUI interface for applications such as embedded systems, digital cameras, personal digital assistants, and mobile phones.

• Embedded systems with graphical user interfaces
• Portable instruments and meters
• Home automation control panels
• Wearable devices
• DIY projects and hobbyist applications, including Arduino-based gadgets

• Display Size: 1.44 inches
• Resolution: 128x128 pixels
• Color Depth: 16-bit (65K colors)
• Interface: SPI (Serial Peripheral Interface)
• Operating Voltage: 3.3V
• Input Data: 8/16-bit parallel interface

1. Power Connections: Connect VCC to a 3.3V power supply and GND to the ground.
2. Data Connections: Connect SDA to the MOSI pin and SCK to the SCK pin of your microcontroller.
3. Control Connections: Connect CS, RESET, and A0/DC to digital I/O pins on your microcontroller.
4. Backlight: Connect LED to a PWM-capable pin for backlight control or directly to 3.3V for constant backlight.

• Always ensure that the power supply is 3.3V; higher voltages can damage the display.
• Use a level shifter if you are interfacing with a 5V microcontroller like the Arduino UNO.
• Avoid exposing the display to direct sunlight or high temperatures to prevent damage.
• When soldering, be cautious not to overheat the pins as it can damage the display.

#include <Adafruit_GFX.h>    // Core graphics library
#include <Adafruit_ST7735.h> // Hardware-specific library for ST7735

#define TFT_CS     10 // Chip select line for TFT display
#define TFT_RST    9  // Reset line for TFT (or connect to +3V3)
#define TFT_DC     8  // Data/command line for TFT

// Initialize Adafruit ST7735 TFT library
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);

void setup() {
  tft.initR(INITR_144GREENTAB); // Initialize display with the correct settings
  tft.fillScreen(ST7735_BLACK);  // Clear the screen to black
}

void loop() {
  // Example: Draw a red rectangle
  tft.fillRect(10, 10, 50, 50, ST7735_RED);
  delay(500);

  // Example: Draw a text string
  tft.setCursor(0, 0);
  tft.setTextColor(ST7735_WHITE);
  tft.setTextWrap(true);
  tft.print("Hello, World!");
  delay(2000);
}

• Display not powering on: Check the power connections and ensure the voltage is 3.3V.
• No display or white screen: Verify that the SPI connections are correct and the CS, RESET, and A0/DC pins are connected properly.
• Garbled or distorted images: Ensure that the library and initialization sequence match the display's specifications.

• Double-check wiring, especially the SPI and control lines.
• Make sure that the correct driver library (Adafruit_ST7735) is installed in your Arduino IDE.
• Reset the display by toggling the RESET pin if the display does not initialize correctly.
• Adjust the contrast or the initialization settings if the display is too dim or too bright.

Q: Can I use this display with a 5V microcontroller? A: Yes, but you will need to use a level shifter to convert the 5V signals to 3.3V to avoid damaging the display.

Q: How can I control the backlight brightness? A: You can control the backlight brightness by connecting the LED pin to a PWM-capable pin on your microcontroller and adjusting the duty cycle.

Q: What library should I use for this display? A: The Adafruit GFX library and the Adafruit ST7735 library are recommended for interfacing with this display.

Q: Can I display images on the TFT LCD? A: Yes, you can display images by converting them into a bitmap array and using the library's functions to draw them on the screen.