How to Use TFT 1.77" SPI ST7735: Examples, Pinouts, and Specs

The TFT 1.77" SPI ST7735 is a compact, full-color thin-film transistor (TFT) display module with a resolution of 128x160 pixels. It utilizes the ST7735 driver IC and communicates via the Serial Peripheral Interface (SPI), making it ideal for embedded systems and microcontroller-based projects. This display is capable of rendering vibrant graphics and text, making it suitable for applications such as user interfaces, data visualization, and gaming.

• Embedded systems requiring graphical displays
• IoT devices with visual feedback
• Portable gaming consoles
• Wearable devices
• Industrial control panels
• Educational projects with microcontrollers like Arduino or Raspberry Pi

Below are the key technical details and pin configuration for the TFT 1.77" SPI ST7735:

1. Power Supply: Connect the VCC pin to a 3.3V power source and the GND pin to ground.
2. SPI Connections:
   • Connect the SCL pin to the SPI clock pin of your microcontroller.
   • Connect the SDA pin to the SPI MOSI pin of your microcontroller.
3. Control Pins:
   • Connect the RES pin to a GPIO pin for resetting the display.
   • Connect the DC pin to a GPIO pin to toggle between data and command modes.
   • Connect the CS pin to a GPIO pin to enable/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 3.3V. If using a 5V microcontroller (e.g., Arduino UNO), use level shifters to avoid damaging the display.
• SPI Speed: Use an appropriate SPI clock speed (typically up to 15 MHz) to ensure reliable communication.
• Initialization: The ST7735 driver requires specific initialization commands. Use a compatible library (e.g., Adafruit GFX and Adafruit ST7735 libraries) to simplify this process.
• Backlight Control: Use a PWM signal on the BLK pin to adjust brightness dynamically.

Below is an example of how to use the TFT 1.77" SPI ST7735 with an Arduino UNO:

#include <Adafruit_GFX.h>      // Graphics library for displays
#include <Adafruit_ST7735.h>   // Library for ST7735 driver

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

// Create an instance of the display
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);

void setup() {
  // Initialize the display
  tft.initR(INITR_BLACKTAB);  // Initialize with ST7735 Black Tab configuration
  tft.setRotation(1);        // Set display orientation (1 = landscape)

  // Clear the screen with a black background
  tft.fillScreen(ST77XX_BLACK);

  // Display a message
  tft.setTextColor(ST77XX_WHITE);  // Set text color to white
  tft.setTextSize(2);              // Set text size
  tft.setCursor(10, 10);           // Set cursor position
  tft.print("Hello, World!");      // Print text to the screen
}

void loop() {
  // Add your code here for dynamic updates
}

• Install the Adafruit GFX and Adafruit ST7735 libraries via the Arduino Library Manager before running the code.
• Adjust the pin definitions (TFT_CS, TFT_RST, TFT_DC) to match your wiring.

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.
   • Confirm that the correct initialization commands are being sent (use a library like Adafruit ST7735).

3. Flickering or Artifacts:

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

4. Incorrect Colors or Orientation:

   • Verify the initialization settings in the code (e.g., INITR_BLACKTAB).
   • Use the setRotation() function to adjust the display orientation.

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

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

Q: What is the maximum SPI clock speed supported?
A: The ST7735 driver typically supports SPI clock speeds up to 15 MHz, but this may vary depending on your microcontroller and wiring quality.

Q: Can I display images on this screen?
A: Yes, you can use libraries like Adafruit GFX to render bitmaps. Ensure the image is converted to the correct format (e.g., 24-bit BMP).

By following this documentation, you can effectively integrate the TFT 1.77" SPI ST7735 display into your projects and troubleshoot common issues.