LittlevGL project for ESP32

LittlevGL ported to the ESP32.

Supported display controllers:

• ILI9341
• ILI9488
• HX8357B/HX8357D
• ST7789

Supported touchscreen controllers:

• XPT2046
• FT3236
• other FT6X36 or the FT6206 controllers should work as well (not tested)
• STMPE610

Get started

Install the ESP32 SDK

http://esp-idf.readthedocs.io/en/latest/

Note:

This project is compatible with both the ESP-IDF 3.X branch and the 4.0 branch. For the 4.0 branch, you can use either make or CMake, but CMake is recommended. Instructions here are given for the latest toolchain using idf.py (which invokes CMake), but it is easy to translate to make. For example instead of running idf.py menuconfig, just run make menuconfig.

Build this repository standalone and run the demo.

Try this first to make sure your hardware is supported, wired and configured properly.

1. Get this project: git clone --recurse-submodules https://github.com/littlevgl/lv_port_esp32.git

2. From its root run idf.py menuconfig

3. Select your display kit or board and other options - see config options

4. idf.py build

5. idf.py -p (YOUR PORT) flash (with make this is just make flash - in 3.x PORT is configured in menuconfig)

Install this project as a library submodule in your own project

It is recommended to install this repo as a submodule in your IDF project's git repo. The configuration system has been designed so that you do not need to copy or edit any files in this repo. By keeping your submodule directory clean you can ensure reproducible builds and easy updates from this upstream repository.

From your project root (you can get the esp32 idf project template here):

1. mkdir -p components
2. git submodule add https://github.com/littlevgl/lv_port_esp32.git components/lv_port_esp32
3. git submodule update --init --recursive
4. Edit your CMake or Makefile to add this repo's components folder to the IDF components path.

CMake

The examples below are taken from the ESP-IDF blink example which you can copy and use as the basis for your own project. The project root CMakeLists.txt file needs one line added, just before the project to add the extra components directory to the path like this:

#CMakeLists.txt
cmake_minimum_required(VERSION 3.5)

include($ENV{IDF_PATH}/tools/cmake/project.cmake)

set(EXTRA_COMPONENT_DIRS components/lv_port_esp32/components/lv_examples components/lv_port_esp32/components/lvgl components/lv_port_esp32/components/lvgl_esp32_drivers/lvgl_tft components/lv_port_esp32/components/lvgl_esp32_drivers/lvgl_touch components/lv_port_esp32/components/lvgl_esp32_drivers)

project(blink)

Temporal workaround

When adding this project as a component you need to update it's CMakeLists.txt file located at the root directory, like so (comment out the include line):

components/lv_port_esp32/CMakeLists.txt

cmake_minimum_required(VERSION 3.5)

# include($ENV{IDF_PATH}/tools/cmake/project.cmake)

set(EXTRA_COMPONENT_DIRS components/lv_port_esp32/components/lv_examples components/lv_port_esp32/components/lvgl components/lv_port_esp32/components/lvgl_esp32_drivers/lvgl_tft components/lv_port_esp32/components/lvgl_esp32_drivers/lvgl_touch components/lv_port_esp32/components/lvgl_esp32_drivers)

if (NOT DEFINED PROJECT_NAME)
	project(lvgl-demo)
endif (NOT DEFINED PROJECT_NAME)

In the CMakeLists.txt file for your /main or for the component(s) using LVGL you need to add REQUIRES directives for this project's driver and lvgl itself to the idf_component_register function, it should look like this:

set (SOURCES main.c)

idf_component_register(SRCS ${SOURCES}
    INCLUDE_DIRS .
    REQUIRES lvgl_esp32_drivers lvgl lv_examples lvgl_tft lvgl_touch)

target_compile_definitions(${COMPONENT_LIB} PRIVATE LV_CONF_INCLUDE_SIMPLE=1)

Please note that if your project require the use of the nvs_flash module (for example required by WiFi), it should be put in the REQUIRES list.

Makefile

If you are using make, you only need to add the EXTRA_COMPONENT_DIRS in the root Makefile of your project:

PROJECT_NAME := blink

EXTRA_COMPONENT_DIRS := components/lv_port_esp32/components/lv_examples \
    components/lv_port_esp32/components/lvgl \
    components/lv_port_esp32/components/lvgl_esp32_drivers/lvgl_tft \
    components/lv_port_esp32/components/lvgl_esp32_drivers/lvgl_touch \
    components/lv_port_esp32/components/lvgl_esp32_drivers \

include $(IDF_PATH)/make/project.mk

Configuration options

There are a number of configuration options available, all accessed through idf.py menuconfig -> Components -> LittlevGL (LVGL).

You can configure the TFT controller and the touch controller (if your display have one)

Touch Controller options

Options include:

• Touch controller options

• Pinout

• SPI Bus: Choose what SPI bus is used to communicate with the touch controller.

• Touchpanel configuration: Maximum and minimum coordinate values, inverting coordinate values, etc.

TFT Controller options

Options include:

• Display controller: Support for the most common TFT display controllers

• SPI Bus: Choose what SPI bus is used to communicate with the tft controller.

• Display resolution - set the height and width of the display

• Invert display - if text and objects are backwards, you can enable this
• Enable backlight control via GPIO (vs hardwiring on)
• Backlight active high or low - some displays expect a high (1) signal to enable backlight, others expect (low) (default) - if your backlight doesn't come on try switching this

Assign the correct pinout depending on your ESP32 dev board

There are several development boards based on the ESP32 chip, make sure you assign the correct pin numbers to the signals that interface with the TFT display board. Its recommended to use a predefined configuration below, but you can also set individual pins for both display controller and touch controller.

Predefined Display Configurations

For development kits that come with a display already attached, all the correct settings are already known and can be selected in menuconfig from the first option "Select predefined display configuration." Once selected all the other options will be defaulted and won't appear in the menu.

Boards we currently have defined this way are:

ESP-Wrover-Kit v4.1

This board comes with an embedded TFT screen with the ILI9341 display driver and it doesn't have touch screen. The screen size is 320 x 240 px.

M5Stack

This board comes with an embedded TFT screen with the ILI9341 display driver and it doesn't have touch screen. The screen size is 240 x 320px.

Predefined Board Pinouts

When wiring the display and touchpad (if applicable) it is best to use the board's designated HSPI and VSPI pins to take advantage of the hardware SPI support. Several board configurations are available; select the appropriate board in the "Select predefined board pinouts" menu in menuconfig and then wire the display and touchpad accordingly.

ESP32 Dev Board with 38 GPIOs

ILI9341 - HSPI

MOSI	CLK	CS	DC	RST	BCKL
13	14	5	19	18	23

XPT2046 - VSPI

MOSI	MISO	CLK	CS	IRQ
32	35	26	33	25

ESP32 DevKit v1 with 30 GPIOS

There is another development kit with only 30 GPIOs available:

ILI9341

For ILI9341 HSPI is used, modify the pin configuration in components/drv/disp_spi.h to:

ILI9341 - HSPI

MOSI	CLK	CS	DC	RST	BCKL
13	14	15	2	4	21

XPT2046 - VSPI

MOSI	MISO	CLK	CS	IRQ
23	19	18	5	25

ESP32 DevKit v4 with 38 GPIOS

See this pdf for further information: https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32d_esp32-wroom-32u_datasheet_en.pdf

ILI9341 - HSPI

MOSI	CLK	CS	DC	RST	BCKL
13	14	15	17	25	26

XPT2046 - VSPI

MOSI	MISO	CLK	CS	IRQ
23	19	18	5	27

Sparkfun ESP32 Thing Plus with Adafruit 3.5" 480x320 TFT Featherwing

Sparkfun ESP32 Thing Plus

Adafruit 3.5" 480x320 TFT Featherwing

The Adafruit Featherwing board uses a HX8357D TFT display controller and a STMPE610 resistive touch controller. Both are hardwired to the same SPI bus (VSPI). The STMPE610 is a strange little beast that configures its SPI mode based on the logic levels on MISO and CS during its power-on reset. The CS signal has a pull-up but the MISO is floating. It appears that it is usually sampled low (setting SPI Mode 1) but you may find you need a pull-down resistor from MISO to ground. A 47-kohm resistor will work fine. The TFT reset and backlight pins are not connected (hardwired on the Featherwing). There is no touchpad IRQ. These signals are connected to unused signals in the following configuration. Note that although I used a Sparkfun ESP32 board, the Adafruit ESP32 featherwing should work identically.

HX8357D - VSPI

MOSI	CLK	CS	DC	RST	BCKL
18	5	15	33	4	2

STMPE610 - VSPI

MOSI	MISO	CLK	CS	IRQ
18	19	5	32	25

Other Boards

Of course, all the individual pins can be configured in menuconfig if the available prefines don't match your board or project requirements. By default the prefined options are disabled and pin settings for the 30 pin dev board are defaulted.