This library supports these boards without any effort.

With the boards, there is a link supplied and there are a lot of examples present and this looks fine. These examples for LVGL depend on external libraries (TFT_eSPI or LovyanGFX). However, when implementing the capacitive version, I found out that these libraries had their flaws using these boards. Additionally, There was a log of unnecessary code included in these libraries. There is also a library for LVGL present LVGL_ESP32_drivers but this is not aimed at the Arduino framework but ESP-IDF framework.

These boards are available on AliExpress for decent prices and offer a lot. They can be bought in the Sunton Store on AliExpress but saw them also from other sellers.

• ESP32-2432S024R/C/N - 2.4" 240x320 TFT Resistive/Capacitive touch/No touch
• ESP32-2432S028R - 2.8" 240x320 TFT Resistive touch
• ESP32-3248S035R/C 3.5" 320x480 TFT Resistive/Capacitive touch
• ESP32-8048S070C/N - 7.0" 800x480 TFT Capacitive touch/No touch

These boards offer:

• ESP32-WROOM,
• 4MB Additional Flash,
• Display with touch (IL9341/ST7796 and XPT2046/GT911),
• Light sensor (CDS),
• Audio amplifier,
• RGB led (3.5" front, 2.8" back),
• Extension connectors,
• USB Serial interface,
• Expansion connectors,
• Power connector,
• 4 Holes so can easily be attached,
• ...

This library depends on some standard libraries to access the SPI and I2C busses:

• SPI (version ^2.0.0)
• Wire (version ^2.0.0) when using capacitive touch

To have all the constants and prototypes from LVGL, the LVGL library is already included.:

• LVGL (version ^8.3.2)

To use the LVGL library, a lv_conf.h file is required to define the settings for LVGL. This file needs to be provided by the application. As this file is referenced from the build of LVGL, the path must be known. Normally this file is included in the include directory of your project so the define must be

    -D LV_CONF_PATH=${PROJECT_INCLUDE_DIR}/lv_conf.h

The template for the lv_conf.h file can be found in the LVGL library at .pio/libdeps/esp32dev/lvgl/lv_conf_template.h.

Basically there is only ONE define that need to be defined: The type of board assuming everything is default.

• Type of board (required)

  • ESP32_2432S024R
  • ESP32_2432S024C
  • ESP32_2432S024N
  • ESP32_2432S028R
  • ESP32_3248S035R
  • ESP32_3248S035C
  • ESP32_8048S070N
  • ESP32_8048S070C

• Orientation of the board (optional)

  • TFT_ORIENTATION_PORTRAIT (default)
  • TFT_ORIENTATION_LANDSCAPE (rotated 90 degrees)
  • TFT_ORIENTATION_PORTRAIT_INV (rotated 180 degrees)
  • TFT_ORIENTATION_LANDSCAPE_INV (rotated 270/-90 degrees)

• Flipped/Mirrored (optional) Some TFT batches seem to have the contents mirrored and flipped. The flag TFT_FLIPPEDMIRRORED compensates for this (production?) anomaly.

• LCD Panel RGB order (if red and blue are swapped on the display, optional)

  • TFT_PANEL_ORDER_RGB
  • TFT_PANEL_ORDER_BGR (default)

These can be defined in the platformio.ini file defining the settings:

build_flags =
    # LVGL settings
    -D LV_CONF_PATH=${PROJECT_INCLUDE_DIR}/lv_conf.h
    # Smart display settings
    #-D TFT_PANEL_ORDER_BGR
    #-D TFT_PANEL_ORDER_RGB
    #-D TFT_ORIENTATION_PORTRAIT
    #-D TFT_ORIENTATION_LANDSCAPE
    #-D TFT_ORIENTATION_PORTRAIT_INV
    #-D TFT_ORIENTATION_LANDSCAPE_INV
    #-D TFT_FLIPPEDMIRRORED
    #-D ESP32_2432S024N
    #-D ESP32_2432S024R
    #-D ESP32_2432S024C
    #-D ESP32_2432S028R
    #-D ESP32_3248S035R
    #-D ESP32_3248S035C
    #-D ESP32_8048S070N
    #-D ESP32_8048S070C

lib_deps =
    rzeldent/esp32_smartdisplay@^1.0.9

The path for the lv_conf.h above is ${PROJECT_INCLUDE_DIR}. This needs to be specified because the LVGL library included this header file.

An bare minimum application to demonstrate the library can be found at esp32-smartdisplay-demo.

This mutex is defined to limit the access to lvgl functions to one thread. When used in multiple threads, this corrupts the display and/or state of LVGL

Use like this:

const std::lock_guard<std::recursive_mutex> lock(lvgl_mutex);

During the scope of this variable, the mutex is locked. This will allow only one thread or section to use lvgl.

Initialize the display and touch. This is the first function that needs to be called. It initializes the display controller and touch controller.

Set the color of the led. The led has 3 channels: R(ed), G(reen) and B(lue). Each channel has a 8 bit resolution so from 0-255.

The lv_colo32_t can be set in the following manner:

lv_color32_t({.ch = {.green = 0xFF}}) : lv_color32_t({.ch = {.red = 0xFF}})

Get the value of the CDS sensor. The sensor measures the (ambient) light level and can be used to adjust the brightness of the display.

Beep with the specified frequency and duration. To hear the sound a 8 ohms speaker must be connected.

Set the brightness of the backlight display. The resolution is 12 bit so 0-1023.

Put the display to sleep.

Wake the display.

• October 2023
  • Added option for flipped/mirrored TFT's
  • Changed default RGB order to BGR
  • Version 1.0.8 and 1.0.9
• September 2023
  • Added support for ESP32_2432S024N/R/S
  • Version 1.0.7
• August 2023
  • Added support for esp32_8048S070N/S
  • Display buffer size configurable
• February 2023
  • Version 1.0.3
  • Added variable for the LCD panel RGB/BGR order
• February 2023
  • Version 1.0.3
  • Added mutex for access to lvgl, required for multithreading
  • Changed RGB led input to lv_color32_t
• December 2022
  • Initial version 1.0.2.
  • Drivers for ESP32_2432S028R, ESP32_3248S035R and ESP32_3248S035C displays working.
  • Sound output
  • RGB Led output
  • CDS light sensor input
• July 2022
  • Initial work started