TFT LCD Displays

There are a few common TFT display drivers on the electronics hobbyist market, and a handful of libraries that work with them. TFT displays are high resolution and full color, unlike the OLED or ePaper displays mentioned in this repository. Most libraries for color TFT displays implement the usual 24-bit RGB color space, where 0xFF0000 is red, 0x00FF00 is green, and 0x0000FF is blue.

You can find the code examples at this link.

TFT displays can be slow to update. Therefore, it’s sometimes usefil to draw only part of the display at once. Adafruits GFX library includes a Canvas class, which lets you update elements offscreen and then draw them. It doesn’t speed up the display, but it can simplify drawing a subset of the screen. See this example to see it in use. Other libraries don’t include a canvas, but you can draw a filled rectangle over part of the screen and then draw on top of it, as shown in this example for the ILI9225.

Hardware

The TFT boards I have encountered so far have had either Sitronix or Ilitek interfaces. The models are detailed below.

Pin Connections

Most TFT displays tend to have an SPI interface, with some extra pins, as explained on the main page of this repo. Some displays, like MakerFocus’ 1.3” TFT, do not implement the CS pin. For this board and others like it, initializing them with SPI_MODE3 works.

Sitronix ST7735 and ST7789 TFT Displays

All of the displays listed below have been tested with the Adafruit_ST7735/ST7789 libraries and the Adafruit_GFX library, with the modifications mentioned below.

• Adafruit 1.8” ST7735R display with MicroSD Breakout
• Adafruit 1.44” ST7735R display with MicroSD Breakout
• Adafruit 1.54” ST7789 Display with MicroSD
• Adafruit 1.14” Display with MicroSD
• MakerFocus 1.3” LCD Display, no MicroSD, Amazon link - This display does not have a CS pin, so it can’t be used with other SPI devices at the same time. It works with the Adafruit_ST7789 library, but you have to change the init() function to include the SPI mode like so: display.init(width, height, SPI_MODE3);.
• DFRobot 7687S round display
  • DFRobot library for this display
  • DFRobot Display library

Ilitek-based displays:

ILI9225

• Datasheet
• Tinkersphere breakout board for this display
• ILI9225 library from Nkawu

Libraries

There’s no standard library for TFT screens, unfortunately. Vendors tend to support the displays they make in their own breakout boards, and not others. As with other types of displays, a well-supported library like the Adafruit libraries makes the display worth more, but limits you to the types of displays that vendor offers. Display manufacturers like Ilitek and Sitronix do not appear to release their own libraries for their displays.

ST7735/7789

The Adafruit_ST7735/7789 library and Adafruit_GFX library works well with some of the Sitronix boards above. It does not support the DFRobot ST7867S board, however.

ST7687S

The DFRobot_ST7687S library has slow refresh rate on the ST7687S board. It’s unclear whether the issue is the library or the board, however. I have yet to find another library to use with this display, though there are a couple other vendors for the board itself on Amazon. Unfortunately the u8g2 library doesn’t support this display, though it does support many of the Sitronix boards.

ILI9225

The TFT_22_ILI9225 library works with this display, and its methods are well documented. Its graphics API is different than some of the other graphics libraries, and doesn’t implement the Printable API, so you can’t use commands like print() and println() with it. It has its own drawText() method instead, which takes an Arduino String object. It comes with a few built-in fonts, and includes many of the Adafruit GFX fonts, and you can generate your own fonts using the The squix.ch custom font generator. Set the settings to

• Preview Display: TFT 2.4”
• Library Version: Adafruit GFX

Like other color TFT libraries, its color scheme is a standard RGB hexadecimal code, where 0xFF0000 is red, 0x00FF00 is green, and 0x0000FF is blue.