Rust ESP32S3 Lvgl Clickme

The purpose of this demo is to get lv-binding-rust (Lvgl) running on the ESP32S3 development board and to use the touchscreen.

Development Board

Aliexpress ESP32-8048S070 - 7 inch 800x400 TN RGB with ESP32S3, 8M PSRAM, 16M Flash, 512KB SRAM

Overview

This application shows how to use lv-binding-rust crate on a ESP32S3 device along with the touchscreen. The program will display a large button that shows "Click me!". When the user clicks the button the button will now show "Clicked!"

partition-table folder

The partition-table folder contains a file called partitons.csv. This file increases the default factory/app partiton from the default of 1M to 3M. This allows us more space for our program and since the flash size is 16M this should not be a problem. This file will be called when we flash the device.

custom-fonts folder

I left the custom-fonts folder in the project but currenly I am not using a custom but but instead using the LV_FONT_MONTSERRAT_28 enabled in the lv_conf.h file. I also made the LV_FONT_MONTSERRAT_28 as the LV_FONT_DEFAULT. The custom-fonts folder contains our custom fonts. The customs fonts are converted from TTF fonts using lvgl online font converter at https://lvgl.io/tools/fontconverter. I used https://ttfonts.net to find a font I liked and then downloaded the font. In the lvgl-online-font-converter I used the font name plus the font size for the name of the font. I chose Bpp of 2 bit-per-pixel and set the range of 0x30-0x3A since I only need numbers and the ":" character. After clicking on "Convert" the file will be downloaded. I placed this downloaded file (*.c) into the custom-fonts folder. Then I created a header file which has an extern to my *.c file, along with changing the ifndef and define names. To use this custom font, I added LVGL_FONTS_DIR = {relative = true, value = "custom-fonts"} to my config.toml under [env]. This allows our font to be compiled when lvgl is compiled.

lvgl-configs folder

The lvgl-configs folder holds the lv_config.h and lv_drv_conf.h files which are required by lvgl to compile. Everything in lv_drv_conf.h file is set to 0 as I am not using the lvgl drivers. I the only thing I changed in the lv_conf.h file was I added additional font (LV_FONT_MONTSERRAT_28) and changed the default font (LV_FONT_DEFAULT &lv_font_montserrat_28).

lcd_panel.rs file

The LCD RGB panel driver.

gt911.rs file

The GT911 touchscreen controller driver.

sdkconfig.defaults file

The following needs to be added for using PSRAM.

CONFIG_SPIRAM=y
CONFIG_SPIRAM_MODE_OCT=y
CONFIG_SPIRAM_SPEED_80M=y

# Enabling the following configurations can help increase the PCLK frequency in the case when
# the Frame Buffer is allocated from the PSRAM and fetched by EDMA
CONFIG_SPIRAM_FETCH_INSTRUCTIONS=y
CONFIG_SPIRAM_RODATA=y

Cargo.toml project file

I have the following to the "dependencies" section.

[dependencies]
# Logging
log = { version = "0.4", default-features = false }

# ESP specifics
esp-idf-svc = { version = "0.51", features = ["critical-section", "embassy-time-driver", "embassy-sync", "alloc"] }

# LVGL
lvgl = { version = "0.6.2", default-features = false, features = [
    "embedded_graphics",
    "unsafe_no_autoinit",
    #"lvgl_alloc",
    #"alloc"
] }

lvgl-sys = { version = "0.6.2" }

# Hardware IO Abstraction Layer
embedded-hal = {version = "1.0.0"}
embedded-graphics-core = "0.4.0"

# Error
anyhow = "1.0"

# C String
cstr_core = "0.2.1"

I also included patch.crates-io section to patch esp-idf-sys, lvgl and lvgl-sys

[patch.crates-io]
lvgl = { git = "https://github.com/enelson1001/lv_binding_rust"}
lvgl-sys = { git = "https://github.com/enelson1001/lv_binding_rust"}

config.toml

To get lv-bindings-rust to comple and build I made the following changes to the config.toml file.

[build]
target = "xtensa-esp32s3-espidf"

[target.xtensa-esp32s3-espidf]
linker = "ldproxy"
runner = "espflash flash --monitor"
rustflags = [ "--cfg",  "espidf_time64",]

[unstable]
build-std = ["std", "panic_abort"]

[env]
MCU="esp32s3"

# Note: this variable is not used by the pio builder (`cargo build --features pio`)
ESP_IDF_VERSION = "v5.2.3"

# The directory that has the lvgl config files - lv_conf.h, lv_drv_conf.h
DEP_LV_CONFIG_PATH = { relative = true, value = "lvgl-configs" }

# Required to make lvgl build correctly otherwise get wrong file type (ie compiled for a big endian system and target is little endian)
CROSS_COMPILE = "xtensa-esp32s3-elf"

# Required for lvgl otherwise the build would fail with the error -> dangerous relocation: call8: call target out of range
# for some lvgl functions
CFLAGS_xtensa_esp32s3_espidf="-mlongcalls"

# Directory for custom fonts (written in C) that Lvgl can use
LVGL_FONTS_DIR = {relative = true, value = "custom-fonts"}

# Required for lvgl to build otherwise you will get string.h not found.
# Verfiy path and toolchain version being used on your PC (esp-14.2.0_20240906)
TARGET_C_INCLUDE_PATH = "/home/ed/.rustup/toolchains/esp/xtensa-esp-elf/esp-14.2.0_20240906/xtensa-esp-elf/xtensa-esp-elf/include"

lv-binding-rust fork

I updated my fork of lv-binding-rust to include PR153 ie the changes recommended by madwizard-thomas and merged with Master commit d83b374

Flashing the ESP32S3 device

I used the following command to flash the ESP32S3 device.

$ cargo espflash flash --partition-table=partition-table/partitions.csv --monitor

Picture of Aliexpress ESP32S3 running the demo

The picture quality is pretty poor but you get the idea what you should be seeing.

The click me

The clicked

Versions

v1.0 :

• initial release

Change History

Feb 04, 2025 - Use latest lv_binding_rust commit d83b374, use esp-idf-svc v0.51