Rust ESP32S3 Lvgl Demo

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

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. The program will display a clock time on a blue backgound screen. The clock time is a simulated time of 21:00 to 21::59 where the seconds are incremented each second and repeats the 00-59 seconds forever.

Comments

I use linux-mint as my development PC and I had to install gcc-multilib or else I got an error 'bits/libc-header-start.h' file not found.

$ sudo apt update
$ sudo apt upgrade
$ sudo apt-get install gcc-multilib

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

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 don't think I changed anything in the lv_conf.h file.

lcd_panel.rs file

The LCD RGB display driver.

sdkconfig.defaults file

Increased the main task stack size to 60000 to allow app to run without crashing.

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 added the following to the "dependencies" section.

esp-idf-hal = { version = "0.42.5" }
esp-idf-sys = { version = "0.33.7"}

cstr_core = "0.2.1"
embedded-graphics-core = "0.4.0"

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

lvgl-sys = { version = "0.6.2" }

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

[patch.crates-io]
esp-idf-sys = { git = "https://github.com/esp-rs/esp-idf-sys"}
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-esp32-espidf"

[target.xtensa-esp32-espidf]
linker = "ldproxy"
# runner = "espflash --monitor" # Select this runner for espflash v1.x.x
runner = "espflash flash --monitor" # Select this runner for espflash v2.x.x
rustflags = [
    # Extending time_t for ESP IDF 5: https://github.com/esp-rs/rust/issues/110
    "--cfg",
    "espidf_time64",

    # Added the following 2 entries so lvgl will build without getting string.h file not found
    "--sysroot",
    "/home/ed/.rustup/toolchains/esp/xtensa-esp32s3-elf/esp-13.2.0_20230928/xtensa-esp-elf/xtensa-esp-elf/include",
]

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

[env]
MCU = "esp32"
# Note: this variable is not used by the pio builder (`cargo build --features pio`)
ESP_IDF_VERSION = "v5.1.1"

# 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
CROSS_COMPILE = "xtensa-esp32-elf"

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

lv-binding-rust fork

I updated my fork of lv-binding-rust to include PR153 ie the changes recommended by madwizard-thomas.

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

Versions

v1.0 :

• initial release