| Supported Targets | ESP32 | ESP32-S2 | ESP32-S3 | | ----------------- | ----- | -------- | -------- | # LVGL porting example (based on i80 interfaced LCD controller) LVGL is an open-source graphics library for creating modern GUIs. It has plenty of built-in graphical elements with low memory footprint, which is friendly for embedded GUI applications. This example can be taken as a skeleton of porting the LVGL library onto the `esp_lcd` driver layer. **Note** that, this example only focuses on the display interface, regardless of the input device driver. The whole porting code is located in [i80_controller_example_main.c](main/i80_controller_example_main.c), and the UI demo code is located in [lvgl_demo_ui.c](main/lvgl_demo_ui.c). The UI will display two images (one Espressif logo and another Espressif text), which have been converted into C arrays by the [online converting tool](https://lvgl.io/tools/imageconverter), and will be compiled directly into application binary. This example is constructed by [IDF component manager](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/tools/idf-component-manager.html), all the external dependency will be handled by the CMake build system automatically. In this case, it will help download the lvgl from [registry](https://components.espressif.com/component/lvgl/lvgl), with the version specified in the [manifest file](main/idf_component.yml). This example uses the [esp_timer](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/esp_timer.html) to generate the ticks needed by LVGL. For more porting guides, please refer to [LVGL porting doc](https://docs.lvgl.io/master/porting/index.html). ## How to use the example ### Hardware Required * An ESP development board * An Intel 8080 interfaced (so called MCU interface or parallel interface) LCD (this example can use ST7789, NT35510 or ILI9341) * An USB cable for power supply and programming ### Hardware Connection The connection between ESP Board and the LCD is as follows: ``` ESP Board LCD Screen ┌─────────────┐ ┌────────────────┐ │ │ │ │ │ 3V3 ├─────────────►│ VCC │ │ │ │ │ │ GND ├──────────────┤ GND │ │ │ │ │ │ DATA[0..7] │◄────────────►│ DATA[0..7] │ │ │ │ │ │ PCLK ├─────────────►│ PCLK │ │ │ │ │ │ CS ├─────────────►│ CS │ │ │ │ │ │ D/C ├─────────────►│ D/C │ │ │ │ │ │ RST ├─────────────►│ RST │ │ │ │ │ │ BK_LIGHT ├─────────────►│ BCKL │ │ │ │ │ │ │ └────────────────┘ │ │ LCD TOUCH │ │ ┌────────────────┐ │ │ │ │ │ I2C SCL ├─────────────►│ I2C SCL │ │ │ │ │ │ I2C SDA │◄────────────►│ I2C SDA │ │ │ │ │ └─────────────┘ └────────────────┘ ``` The GPIO number used by this example can be changed in [i80_controller_example_main.c](main/i80_controller_example_main.c). Especially, please pay attention to the binary signal level used to turn the LCD backlight on, some LCD modules need a low level to turn it on, while others require a high level. You can change the backlight level macro `EXAMPLE_LCD_BK_LIGHT_ON_LEVEL` in [i80_controller_example_main.c](main/i80_controller_example_main.c). ### Build and Flash Run `idf.py set-target <target-name>` to select one supported target that can run this example. This step will also apply the default Kconfig configurations into the `sdkconfig` file. Run `idf.py menuconfig` to open a terminal UI where you can tune specific configuration for this example in the `Example Configuration` menu. * `i80 LCD controller model`: Choose the LCD model to use by the example. If you choose `NT35510`, there will be another relevant configuration `NT35510 Data Width`, to choose the data line width for your NT35510 LCD module. * `Allocate color data from PSRAM`: Select this option if you want to allocate the LVGL draw buffers from PSRAM. Run `idf.py -p PORT build flash monitor` to build, flash and monitor the project. A fancy animation will show up on the LCD as expected. The first time you run `idf.py` for the example will cost extra time as the build system needs to address the component dependencies and downloads the missing components from registry into `managed_components` folder. (To exit the serial monitor, type ``Ctrl-]``.) See the [Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/latest/get-started/index.html) for full steps to configure and use ESP-IDF to build projects. ### Example Output ```bash I (0) cpu_start: Starting scheduler on APP CPU. I (418) example: Turn off LCD backlight I (418) gpio: GPIO[2]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0 I (428) example: Initialize Intel 8080 bus I (438) example: Install LCD driver of st7789 I (558) example: Turn on LCD backlight I (558) example: Initialize LVGL library I (558) example: Register display driver to LVGL I (558) example: Install LVGL tick timer I (558) example: Display LVGL animation ``` ## Touch Screen Support This example supports touch screen connected via I2C. You can enable it by running `idf.py menuconfig` and navigating to `Example Configuration -> Enable LCD touch`. When touch is enabled, there will be a new button in the GUI that can restart the animation. These touch controllers are supported: * [GT911](https://github.com/espressif/esp-bsp/tree/master/components/lcd_touch/esp_lcd_touch_gt911) * [TT21100](https://github.com/espressif/esp-bsp/tree/master/components/lcd_touch/esp_lcd_touch_tt21100) * [FT5X06](https://github.com/espressif/esp-bsp/tree/master/components/lcd_touch/esp_lcd_touch_ft5x06) ## Troubleshooting * Can't get a stable UI when `EXAMPLE_LCD_I80_COLOR_IN_PSRAM` is enabled. This is because of the limited PSRAM bandwidth, compared to the internal SRAM. You can either decrease the PCLK clock `EXAMPLE_LCD_PIXEL_CLOCK_HZ` in [i80_controller_example_main.c](main/i80_controller_example_main.c) or increase the PSRAM working frequency `SPIRAM_SPEED` from the KConfig (e.g. **ESP32S3-Specific** -> **Set RAM clock speed**) or decrease the FPS in LVGL configuration. For illustration, this example has set the refresh period to 100ms in the default sdkconfig file. For any technical queries, please open an [issue] (https://github.com/espressif/esp-idf/issues) on GitHub. We will get back to you soon.