st7789 tft display module free sample

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).

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

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.

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.

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).

This is a graphics library for the family of small colour TFT displays based on the ST7735 and ST7789 driver chips. These are really nice displays; bright, colourful, available in a variety of useful sizes, and available at low cost from suppliers like Adafruit, AliExpress, or Banggood:

This library allows you to plot points, draw lines, draw filled rectangles, and plot text with an optional scale factor. I"ve included a demo histogram-plotting program that adjusts itself to fit each of the displays I"ve supported.

Unlike most other TFT display libraries this one doesn"t require a memory buffer, allowing it to be run on any processor down to an ATtiny85. The displays are SPI and require four pins to drive the display, leaving one pin free on an ATtiny85 to interface to another device, such as a temperature sensor. If you need more pins choose a larger chip, such as the ATtiny84; see Using the library with other AVR chips at the end of the article for information about how to convert the code for different chips.

I"ve published a library for a colour OLED display in a previous article: Colour Graphics Library. The main difference between the colour TFT displays and the colour OLED displays is that the TFT displays are not self-illuminating, and so need a backlight; they therefore have a slightly higher power consumption. However, they are exceedingly cheap, and they are available in larger sizes than the colour OLED displays.

This library will work with displays based on the ST7735 which supports a maximum display size of 132 (H) x 162 (V), or the similar ST7789 which supports a maximum display size of 240 (H) x 320 (V).

The display driver interfaces to the displays with the longer side as the vertical dimension, which is why the rectangular displays are usually listed with the longer dimension second. My library allows you to rotate the image for any desired orientation.

All the Adafruit breakout boards for these displays include level-shifting circuitry, so they will work with either 5V or 3.3V microcontroller boards. They also include an SD card socket, if that"s of interest to you. The Adafruit boards have pullups on the backlight and reset pins, so the display will work if you leave these pins unconnected.

The pullup resistor from the display"s CS pin is optional; it holds the chip select high to prevent the display from being affected by the ISP signals while programming the ATtiny85.

The different displays are catered for by six constants which specify the size of the display, the offsets relative to the area supported by the display driver, whether the display is inverted, and the rotation value; for example:

Note that on some displays you may also have to change the xoff or yoff value when rotating the display. For example, to rotate the image on the 240x240 displays by 180° use the settings:

To check or adjust the values for each display I ran this program, which draws a one-pixel border around the display area, and plots an "F" to show the orientation:

The ATtiny85 and other AVR processors supports toggling of one or more bits in a port, so provided you set all the pins to their disabled state at startup, for speed the display access routines can simply toggle the appropriate pins to enable or disable them.

The InitDisplay() routine first defines the four display pins as outputs, and takes the SCK, DC, and CS pins high (inactive). It then sends the essential configuration commands to the display.

The display memory stores 18 bits per pixel: 6 bits per colour. However, you can write to the display in three alternative modes, with 12, 16, or 18 bits per pixel. I chose the 16 bit mode, which assigns 5 bits to red, 6 bits to green, and 5 bits blue. It"s the most convenient one to work with as you simply send two bytes to define the colour of each pixel.

To clear the display the ClearDisplay() routine sends the appropriate number of zero bytes. The routine temporarily switches to 12-bit colour mode, which reduces the time to clear the display by 25%:

The library includes basic graphics routines for plotting points and drawing lines. These work on a conventional coordinate system with the origin at lower left. For example, on the 80x160 display:

My first version of PlotChar() plotted characters by calling PlotPoint() for each pixel. However, I then tried the following alternative approach which defines an area of the display using the CASET (Column Address Set) and RASET (Row Address Set) commands, and then sends a stream of the appropriate bytes to define the character. This turned out to be over three times faster!

14th January 2020: Tested the program with the Adafruit 1.3" 240x240 TFT display, and updated the program to correct a problem when rotating the image on that display.

It works with TFT displays available from AliExpress, and I"ve included four examples showing how you can do things that wouldn"t be possible without the ability to read from the display.

You can use an exclusive-OR drawing mode that changes the state of pixels reversibly. Drawing the same thing a second time restores the display to its previous state. This is especially important for dynamic data plotting.

To implement these applications without the ability to read pixels from the display would require you to keep a mirror of the display in RAM, and update the mirror every time you draw to the actual display. This would slow down graphics and require a lot of memory: for example, to mirror a 320x240 colour display would require 153.6Kbytes of RAM. To put this in context, the ATtiny414 used to run these examples only has 256 bytes of RAM.

Unfortunately this feature does not work with Adafruit displays, which is why I didn"t include it in my original Tiny TFT Graphics Library 2. It is, however, compatible with all displays based on the ST7735 and ST7789 driver chips available from vendors such as AliExpress and Banggood. Here"s a list of displays I"ve tested:

Adafruit have a range of great TFT displays, in a wide selection of sizes and resolutions, but unfortunately they are not compatible with this library. The reason is that their displays all include a unidirectional on-board logic-level converter to allow them to be used with either 3.3V or 5V, but this has the downside of preventing them from being able to read back from the display memory.

The solution would be to replace the unidirectional logic-level converter on the MOSI connection to the display driver with a bidirectional one, which would require one N-MOSFET and two resistors. I originally planned to include details of how to modify an Adafruit display to implement this, but I"ve decided against this because the displays are fragile, and the risk of ending up with a non-functional display is too great.

This first uses the display commands CASET and RASET to set the column range and row range to the current point. It then gives the RAM read command, RAMRD.

The sequence to shift the 21 bits into the variable pixel needs to be slightly different depending on whether the display uses the ST7735 or ST7789 driver chip. The two if statements determine this from the width of the display, and toggle the sck pin either before or after reading the mosi pin, as appropriate. It took a bit of experimentation to figure this out.

These examples included with the library demonstrate applications of reading back from the display memory. For convenience I"ve used my Universal TFT Display Backpack to run these examples, but that"s not necessary.

This simple demo takes a triangular section of an existing image on the screen, and reflects it through horizontal, vertical, and diagonal lines to create a symmetrical image, like a kaleidoscope. It works best on square displays; here it is on a 240x240 1.54" display:

To run it first draw an image, and then run Kaleidoscope(). For this example the initial image is the Waterfall() demo, used for the title image in the article Tiny TFT Graphics Library 2:

The stopwatch takes advantage of exclusive-OR plotting to draw and undraw the hand when it moves without corrupting the clock face. It is designed for a 128x128 display:

Anything drawn in red on the display is treated as a barrier, and the ball will bounce off it. Any other colours, such as the white text, are ignored and can be used to create an interesting background.

The final demo draws the BarChart() demo, and it then calls BMPSave() to save it to a BMP-format image file on an SD card. Here"s the BarChart() demo running on a 320x170 display:

Here is the version of the Tiny TFT Graphics Library with the extensions for reading from the display, and the demos described above (excluding BMPSave()): Tiny TFT Graphics Library with Read.

There are several popular libraries out there that work with this display. It took me a little longer to get it working than I expected but that was because with no CS pin, the SPI mode needs to be set to SPI_MODE2. With that set, it works like a charm!

This display (like many others) is very fragile and will be damaged if it’s not protected. The one I received came in a small plastic box that no longer fit when I soldered the pins on so I cut a small hole in the box so the pins could stick through.

The TFT display provides a semiconductor switch for each pixel and each pixel is directly controlled by pulse. Therefore, each node is relatively independent and can be continuously controlled, which not only improves the response speed of the display, but also can be accurately controlled. The color level is displayed to make the TFT LCD color more realistic, the brightness is good, the contrast is high, the layering is strong and the color is bright.

The Capacitive touch panel is activated with anything containing an inductive load such as a finger or stylus. It allows for multi-touch options. When using the capacitive touch screen, the display needs a separate controller to interface with the touch panel. The display for capacitive touch is brighter since the touch panel is transparent.

The Transmissive polarizer is best used for displays that run with the backlight on all the time. This polarizer provides the brightest backlight possible. If you have a need for a bright backlight with lower power drain, transmissive is a good choice for this thin-film transistor.

Focus LCDs can provide many accessories to go with your display. If you would like to source a connector, cable, test jig or other accessory preassembled to your LCD (or just included in the package), our team will make sure you get the items you need.Get in touch with a team member today to accessorize your display!

Focus Display Solutions (aka: Focus LCDs) offers the original purchaser who has purchased a product from the FocusLCDs.com a limited warranty that the product (including accessories in the product"s package) will be free from defects in material or workmanship.

ER-TFT028A3-4 is 240x320 dots 2.8" color tft lcd module display with ST7789V controller and optional capacitive touch panel and 4-wire resistive touch panel,superior display quality,super wide viewing angle and easily controlled by MCU such as 8051, PIC, AVR, ARDUINO ARM and Raspberry PI.It can be used in any embedded systems,industrial device,security and hand-held equipment which requires display in high quality and colorful image.It supports 8080 8-bit,9-bit,16-bit,18-bit parallel,3-wire,4-wire serial spi interface. FPC with zif connector is easily to assemble or remove.Lanscape mode is also available.

Of course, we wouldn"t just leave you with a datasheet and a "good luck!".Here is the link for 2.8"TFT Touch Shield with Libraries, Examples.Schematic Diagram for Arduino Due,Mega 2560 and Uno . For 8051 microcontroller user,we prepared the detailed tutorial such as interfacing, demo code and development kit at the bottom of this page.