Arduino Interface with ST7789 Color TFT Display

Adding a display to an embedded system can significantly enhance its functionality by providing visual feedback and an interactive user interface. This tutorial shows how to interface Arduino development board with ST7789 color TFT display.

TFT: Thin-Film Transistor.
SPI: Serial Peripheral Interface.
IPS: In-Plane Switching.
MOSI: Master Out Slave In.
MISO: Master In Slave Out.
DIY: Do-It-Yourself

ATmega328P Based Arduino UNO board with ST7789 TFT display

The ST7789 Color TFT Display:
The ST7789 is a display controller/driver chip for 262K-color, graphic type TFT-LCD, originally manufactured by Sitronix Technology Corp ( —ST7789 datasheet— ).
The ST7789 display is commonly used in projects involving microcontrollers like Arduino, ESP32, and Raspberry Pi. Here are some key features and aspects of the ST7789 TFT display:

  • Display Controller: This display is based on a controller chip of the same name, ST7789 (or, ST7789V, ST7789VW), providing an interface between the master device and the display panel.
  • Color TFT-LCD: It is specifically designed for color displays, supporting 16-bit (65,536 colors) and 18-bit (262,144 colors) color modes, providing rich color display capabilities.
  • Resolution: The ST7789 displays come with different resolutions (320×240 pixel, 240×240 pixel…) supporting landscape and portrait orientations. Common resolutions are 240×240 pixels and 240×320 pixels.
  • Communication Interface: It usually interfaces with microcontrollers or other devices using SPI (Serial Peripheral Interface).
  • Supported Operations: The ST7789 TFT display supports standard display operations such as drawing pixels, lines, rectangles, and displaying images.
  • Display Orientation: Can be rotated to multiple orientations (0, 90, 180, 270 degrees) through software commands.
  • Low Power Consumption: It is designed to be power-efficient, suitable for battery-powered or low-power devices.
  • Voltage Levels: The ST7789 typically works 3.3V, and the specific requirements may vary based on the module or display being used.
  • Widely Used in Projects: The ST7789 is often used in DIY electronics projects, especially those involving microcontrollers like Arduino, Raspberry Pi, STM32, and others.

The following image shows a ST7789 display module provided by Adafruit Industries:

Adafruit ST7789 TFT display module

Another version of the ST7789 display module is shown below, it is the one used in this tutorial. This one has no CS (chip select) pin that internally attached to GND. The resolution of this display is 240×240 pixel.

ST7789 TFT display 240x240 pixels


ST7789 color TFT display module pin description:

  • GND: Ground connection pin.
  • VCC: Power supply voltage pin.
  • SCL: Serial Clock pin. Connected to the SPI clock pin of the master device.
  • SDA: Serial Data Input pin. Connected to the SPI MOSI (Master Out Slave In) pin of the master device.
  • RES: Reset signal pin. Connected to a digital output pin on the master device. It is often optional, and if not used, it could be connected to master device reset pin or tied to a stable low level point.
  • DC (Data/Command): Data/Command control signal. Connected to a digital output pin on the master device. It determines whether the data on the bus is a command or actual pixel data.
  • BLK (Backlight): Backlight control pin. Connected to a digital output or PWM (Pulse Width Modulation) pin on the master device, it could be connected to VCC for maximum and permanent backlight on the display.

If the display has a CS pin:

  • CS: Chip Select pin. Connected to a digital pin on the master device. Used to enable or disable the communication with the ST7789 display.

Hardware Required:

  • Arduino UNO or similar board   —> Board details.
  • ST7789 TFT display module.
  • 4 x 3.3k ohm resistor (+1 if the display module has CS pin).
  • 4 x 2.2k ohm resistor (+1 if the display module has CS pin).
  • Breadboard & jumper wires.

Interfacing Arduino with ST7789 TFT Display Circuit:
Project circuit schematic diagram is shown below.
The ST7789 display module shown in project circuit diagram has 7 pins: (from left to right): GND (ground), VCC, SCL (serial clock), SDA (serial data), RES (reset), DC (or D/C: data/command) and BLK (back light).

Arduino ST7789 TFT display circuit
Arduino UNO board with ST7789 display circuit

The ST7789 display used in this project works with voltage level of 3.3V only, this includes power supply and data/control signals. Note that all Arduino UNO board output pins are 5V, connecting a 5V output pin to the ST7789 TFT display may damage its controller chip.
For the power supply, the ST7789 display is supplied with 3.3V from the Arduino board. For data & control signals, I used resistor voltage divider for each line to scale down the Arduino 5V into 3V. Each voltage divider consists of 2.2k and 3.3k resistors.

Connection between the Arduino and the ST7789 display:
The ST7789 display is connected to the Arduino board as follows:
GND is connected to pin GND of the Arduino board.
VCC and BLK pins are connected to pin 3V3 of the Arduino board.
SCL pin is connected to pin 13 of the Arduino board (through voltage divider).
SDA pin is connected to pin 11 of the Arduino board (through voltage divider).
RST pin is connected to pin 8 of the Arduino board (through voltage divider).
DC pin is connected to pin 9 of the Arduino board (through voltage divider).

If the display module has a CS pin then it should be connected to pin 10 of the Arduino board through another resistive voltage divider.

Pins 13 and 11 are hardware SPI module pins of the ATmega328P microcontroller, respectively for SCK (serial clock) and MOSI (master-out slave-in).

Interfacing Arduino with ST7789 Color TFT Display Code:
Project Arduino code is just an example of graphics test provided by Adafruit Industries, with some minor modifications.
To be able to compile project Arduino code, two libraries are required from Adafruit Industries:

The first library is a driver for the ST7789 TFT display which can be installed from Arduino IDE library manager (Sketch —> Include Library —> Manage Libraries…, in the search box write “st7789” and install the one from Adafruit).
The second library is Adafruit graphics library which can be installed also from Arduino IDE library manager.
During installation of the Adafruit ST7789 library, Arduino IDE may ask for installing some other libraries form Adafruit Industries (dependencies).

Project code was tested with the following library versions:
Adafruit GFX Library: Version 1.11.9.
Adafruit ST7735 and ST7789 Library: Version 1.10.4.

Programming Hints:
The used libraries are included in the Arduino code as shown below:

The connection between the Arduino UNO board and the ST7789 TFT display is as shown in the above circuit schematic, it is defined in the Arduino code as shown below:

The initialization of the ST7789 TFT display library with the connections previously defined:

The ST7789 display must be initialized before any print operation, if the initialization failed then the display will show only black screen. The initialization function of the display is the one below:

If the display failed to initialize properly then you have to try with another SPI Mode, replace SPI_MODE3 by one of the following:

For more details about Arduino SPI communication, see the following page:
Arduino & Serial Peripheral Interface (SPI)

Rest of code is described through comments.

Full Arduino code:

Interfacing Arduino with ST7789 Color TFT Display Video:
The video below shows my DIY test hardware circuit of a Arduino UNO with ST7789 TFT display:

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