kolibri-cyd-tester-app-embassy/lvgl-based

Rust M5Stack Lvgl Demo

The purpose of this demo is to get lv-binding-rust (Lvgl) running on the M5Stack development board

Development Board

M5Stack Basic Development Kit V1.0 with 16M Flash

Overview

This application shows how to use lv-binding-rust crate on the M5Stack. The program displays 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.

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.

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" }

display-interface-spi = "0.4.1"
mipidsi = "0.7.1"

I also included patch.crates-io section to patch 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-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 M5Stack

I used the following command to flash the M5Stack.

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

Picture of M5stack running the demo

Versions

v1.0 :

• initial release