Interfacing Arduino with ST7789 TFT Display – Graphics Test Example
Interfacing Arduino with ST7789 TFT Display – Graphics Test Example
This Arduino tutorial shows how to interface the UNO board with ST7789 TFT display.
The ST7789 TFT module contains a display controller with the same name: ST7789. It’s a color display that uses SPI interface protocol and requires 3, 4 or 5 control pins, it’s low cost and easy to use. This display is an IPS display, it comes in different sizes (1.3″, 1.54″ …) but all of them should have the same resolution of 240×240 pixel, this means it has 57600 pixels. This module works with 3.3V only and it doesn’t support 5V (not 5V tolerant).
TFT: Thin-Film Transistor.
SPI: Serial Peripheral Interface.
IPS: In-Plane Switching.
The following image shows a ST7789 display module provided by Adafruit Industries:
Another version of the ST7789 display module is shown below. This one has no CS (chip select) pin, its internally attached to GND:
Project Hardware Required:
- Arduino UNO board —> ATmega328P datasheet
- ST7789 TFT display module (1.3″, 1.54″ …)
- 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 UNO with ST7789 TFT circuit:
Project circuit schematic diagram is shown below.
The ST7789 display module shown in project circuit diagram has 7 pins: (from to left to right): GND (ground), VCC, SCL (serial clock), SDA (serial data), RES (reset), DC (or D/C: data/command) and BLK (back light).
Connecting the BLK pin is optional. The back light turns off when the BLK pin connected to the ground (GND).
As mentioned above, the ST7789 TFT display controller works with 3.3V only (power supply and control lines). The display module is supplied with 3.3V (between VCC and GND) which comes from the Arduino board.
All Arduino UNO board output pins are 5V, connecting a 5V pin to the ST7789 TFT display may damage its controller.
To connect the Arduino to the display module, I used voltage divider for each line which means there are 4 voltage dividers. Each voltage divider consists of 2.2k and 3.3k resistors, this drops the 5V into 3V which is sufficient.
If the display module has a CS pin (Chip Select) then it should be connected to Arduino digital pin 10 through another voltage divider.
So, the ST7789 TFT display is connected to the Arduino board as follows (each one through voltage divider):
RST pin is connected to Arduino digital pin 8,
DC pin is connected to Arduino digital pin 9,
SDA pin is connected to Arduino digital pin 11,
SCL pin is connected to Arduino digital pin 13.
Other pins are connected as follows:
VCC pin is connected to Arduino 3V3 pin,
GND pin is connected to Arduino GND pin,
BL (LED) pin is connected to Arduino 3V3 pin (optional).
Interfacing Arduino UNO with ST7789 TFT code:
The following Arduino code requires two libraries 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.
Both libraries can be installed manually, first download them from the following 2 links:
Adafruit ST7789 TFT library —-> direct link
Adafruit graphics library —-> direct link
After the download, go to Arduino IDE —> Sketch —> Include Library —> Add .ZIP Library … and browse for the .zip file (previously downloaded).
The same thing for the other library file.
Hints:
The 2 library files are included in the main code as shown below.
Including Arduino SPI library is optional!
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#include <Adafruit_GFX.h> // Core graphics library
#include <Adafruit_ST7789.h> // Hardware-specific library for ST7789
#include <SPI.h> // Arduino SPI library
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The ST7789 TFT module pins (CS, RST and DC) connections are defined as shown below:
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// ST7789 TFT module connections
#define TFT_CS 10 // define chip select pin
#define TFT_DC 9 // define data/command pin
#define TFT_RST 8 // define reset pin, or set to -1 and connect to Arduino RESET pin
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The other display pins (SDA and SCL) are connected to Arduino hardware SPI pins (digital pin 11 and digital pin 13).
The Adafruit ST7789 library is initialized with this line:
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// Initialize Adafruit ST7789 TFT library
Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST);
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And the TFT display is initialized using the following command:
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// if the display has CS pin try with SPI_MODE0
tft.init(240, 240, SPI_MODE2); // Init ST7789 display 240×240 pixel
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The display may not work if it has a CS pin, try with SPI_MODE0 which is the default mode of the library or just use: tft.init(240, 240);
Rest of code is described through comments.
Full Arduino code:
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/*
* Interfacing Arduino with ST7789 TFT display (240×240 pixel).
* Graphics test example.
* This is a free software with NO WARRANTY.
* http://simple-circuit.com/
*/
/**************************************************************************
This is a library for several Adafruit displays based on ST77* drivers.
Works with the Adafruit 1.8″ TFT Breakout w/SD card
—-> http://www.adafruit.com/products/358
The 1.8″ TFT shield
—-> https://www.adafruit.com/product/802
The 1.44″ TFT breakout
—-> https://www.adafruit.com/product/2088
as well as Adafruit raw 1.8″ TFT display
—-> http://www.adafruit.com/products/618
Check out the links above for our tutorials and wiring diagrams.
These displays use SPI to communicate, 4 or 5 pins are required to
interface (RST is optional).
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
MIT license, all text above must be included in any redistribution
**************************************************************************/
#include <Adafruit_GFX.h> // Core graphics library
#include <Adafruit_ST7789.h> // Hardware-specific library for ST7789
#include <SPI.h> // Arduino SPI library
// ST7789 TFT module connections
#define TFT_CS 10 // define chip select pin
#define TFT_DC 9 // define data/command pin
#define TFT_RST 8 // define reset pin, or set to -1 and connect to Arduino RESET pin
// Initialize Adafruit ST7789 TFT library
Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST);
float p = 3.1415926;
void setup(void) {
Serial.begin(9600);
Serial.print(F(“Hello! ST77xx TFT Test”));
// if the display has CS pin try with SPI_MODE0
tft.init(240, 240, SPI_MODE2); // Init ST7789 display 240×240 pixel
// if the screen is flipped, remove this command
tft.setRotation(2);
Serial.println(F(“Initialized”));
uint16_t time = millis();
tft.fillScreen(ST77XX_BLACK);
time = millis() – time;
Serial.println(time, DEC);
delay(500);
// large block of text
tft.fillScreen(ST77XX_BLACK);
testdrawtext(“Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur adipiscing ante sed nibh tincidunt feugiat. Maecenas enim massa, fringilla sed malesuada et, malesuada sit amet turpis. Sed porttitor neque ut ante pretium vitae malesuada nunc bibendum. Nullam aliquet ultrices massa eu hendrerit. Ut sed nisi lorem. In vestibulum purus a tortor imperdiet posuere. “, ST77XX_WHITE);
delay(1000);
// tft print function!
tftPrintTest();
delay(4000);
// a single pixel
tft.drawPixel(tft.width()/2, tft.height()/2, ST77XX_GREEN);
delay(500);
// line draw test
testlines(ST77XX_YELLOW);
delay(500);
// optimized lines
testfastlines(ST77XX_RED, ST77XX_BLUE);
delay(500);
testdrawrects(ST77XX_GREEN);
delay(500);
testfillrects(ST77XX_YELLOW, ST77XX_MAGENTA);
delay(500);
tft.fillScreen(ST77XX_BLACK);
testfillcircles(10, ST77XX_BLUE);
testdrawcircles(10, ST77XX_WHITE);
delay(500);
testroundrects();
delay(500);
testtriangles();
delay(500);
mediabuttons();
delay(500);
Serial.println(“done”);
delay(1000);
}
void loop() {
tft.invertDisplay(true);
delay(500);
tft.invertDisplay(false);
delay(500);
}
void testlines(uint16_t color) {
tft.fillScreen(ST77XX_BLACK);
for (int16_t x=0; x < tft.width(); x+=6) {
tft.drawLine(0, 0, x, tft.height()–1, color);
delay(0);
}
for (int16_t y=0; y < tft.height(); y+=6) {
tft.drawLine(0, 0, tft.width()–1, y, color);
delay(0);
}
tft.fillScreen(ST77XX_BLACK);
for (int16_t x=0; x < tft.width(); x+=6) {
tft.drawLine(tft.width()–1, 0, x, tft.height()–1, color);
delay(0);
}
for (int16_t y=0; y < tft.height(); y+=6) {
tft.drawLine(tft.width()–1, 0, 0, y, color);
delay(0);
}
tft.fillScreen(ST77XX_BLACK);
for (int16_t x=0; x < tft.width(); x+=6) {
tft.drawLine(0, tft.height()–1, x, 0, color);
delay(0);
}
for (int16_t y=0; y < tft.height(); y+=6) {
tft.drawLine(0, tft.height()–1, tft.width()–1, y, color);
delay(0);
}
tft.fillScreen(ST77XX_BLACK);
for (int16_t x=0; x < tft.width(); x+=6) {
tft.drawLine(tft.width()–1, tft.height()–1, x, 0, color);
delay(0);
}
for (int16_t y=0; y < tft.height(); y+=6) {
tft.drawLine(tft.width()–1, tft.height()–1, 0, y, color);
delay(0);
}
}
void testdrawtext(char *text, uint16_t color) {
tft.setCursor(0, 0);
tft.setTextColor(color);
tft.setTextWrap(true);
tft.print(text);
}
void testfastlines(uint16_t color1, uint16_t color2) {
tft.fillScreen(ST77XX_BLACK);
for (int16_t y=0; y < tft.height(); y+=5) {
tft.drawFastHLine(0, y, tft.width(), color1);
}
for (int16_t x=0; x < tft.width(); x+=5) {
tft.drawFastVLine(x, 0, tft.height(), color2);
}
}
void testdrawrects(uint16_t color) {
tft.fillScreen(ST77XX_BLACK);
for (int16_t x=0; x < tft.width(); x+=6) {
tft.drawRect(tft.width()/2 –x/2, tft.height()/2 –x/2 , x, x, color);
}
}
void testfillrects(uint16_t color1, uint16_t color2) {
tft.fillScreen(ST77XX_BLACK);
for (int16_t x=tft.width()–1; x > 6; x-=6) {
tft.fillRect(tft.width()/2 –x/2, tft.height()/2 –x/2 , x, x, color1);
tft.drawRect(tft.width()/2 –x/2, tft.height()/2 –x/2 , x, x, color2);
}
}
void testfillcircles(uint8_t radius, uint16_t color) {
for (int16_t x=radius; x < tft.width(); x+=radius*2) {
for (int16_t y=radius; y < tft.height(); y+=radius*2) {
tft.fillCircle(x, y, radius, color);
}
}
}
void testdrawcircles(uint8_t radius, uint16_t color) {
for (int16_t x=0; x < tft.width()+radius; x+=radius*2) {
for (int16_t y=0; y < tft.height()+radius; y+=radius*2) {
tft.drawCircle(x, y, radius, color);
}
}
}
void testtriangles() {
tft.fillScreen(ST77XX_BLACK);
int color = 0xF800;
int t;
int w = tft.width()/2;
int x = tft.height()–1;
int y = 0;
int z = tft.width();
for(t = 0 ; t <= 15; t++) {
tft.drawTriangle(w, y, y, x, z, x, color);
x-=4;
y+=4;
z-=4;
color+=100;
}
}
void testroundrects() {
tft.fillScreen(ST77XX_BLACK);
int color = 100;
int i;
int t;
for(t = 0 ; t <= 4; t+=1) {
int x = 0;
int y = 0;
int w = tft.width()–2;
int h = tft.height()–2;
for(i = 0 ; i <= 16; i+=1) {
tft.drawRoundRect(x, y, w, h, 5, color);
x+=2;
y+=3;
w-=4;
h-=6;
color+=1100;
}
color+=100;
}
}
void tftPrintTest() {
tft.setTextWrap(false);
tft.fillScreen(ST77XX_BLACK);
tft.setCursor(0, 30);
tft.setTextColor(ST77XX_RED);
tft.setTextSize(1);
tft.println(“Hello World!”);
tft.setTextColor(ST77XX_YELLOW);
tft.setTextSize(2);
tft.println(“Hello World!”);
tft.setTextColor(ST77XX_GREEN);
tft.setTextSize(3);
tft.println(“Hello World!”);
tft.setTextColor(ST77XX_BLUE);
tft.setTextSize(4);
tft.print(1234.567);
delay(1500);
tft.setCursor(0, 0);
tft.fillScreen(ST77XX_BLACK);
tft.setTextColor(ST77XX_WHITE);
tft.setTextSize(0);
tft.println(“Hello World!”);
tft.setTextSize(1);
tft.setTextColor(ST77XX_GREEN);
tft.print(p, 6);
tft.println(” Want pi?”);
tft.println(” “);
tft.print(8675309, HEX); // print 8,675,309 out in HEX!
tft.println(” Print HEX!”);
tft.println(” “);
tft.setTextColor(ST77XX_WHITE);
tft.println(“Sketch has been”);
tft.println(“running for: “);
tft.setTextColor(ST77XX_MAGENTA);
tft.print(millis() / 1000);
tft.setTextColor(ST77XX_WHITE);
tft.print(” seconds.”);
}
void mediabuttons() {
// play
tft.fillScreen(ST77XX_BLACK);
tft.fillRoundRect(25, 10, 78, 60, 8, ST77XX_WHITE);
tft.fillTriangle(42, 20, 42, 60, 90, 40, ST77XX_RED);
delay(500);
// pause
tft.fillRoundRect(25, 90, 78, 60, 8, ST77XX_WHITE);
tft.fillRoundRect(39, 98, 20, 45, 5, ST77XX_GREEN);
tft.fillRoundRect(69, 98, 20, 45, 5, ST77XX_GREEN);
delay(500);
// play color
tft.fillTriangle(42, 20, 42, 60, 90, 40, ST77XX_BLUE);
delay(50);
// pause color
tft.fillRoundRect(39, 98, 20, 45, 5, ST77XX_RED);
tft.fillRoundRect(69, 98, 20, 45, 5, ST77XX_RED);
// play color
tft.fillTriangle(42, 20, 42, 60, 90, 40, ST77XX_GREEN);
}
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The video below shows my breadboard test circuit:
Related Project:
Arduino Interface with ST7789 Color TFT Display
