ESP32 System Monitor Display

ESP32 part of esp32-sysmon-* project;
Desktop part of this project - requiered to collect metrics for this display

ESP32 SoC requierements and support

It is possible, that with changes to source code ESP32's without exact requiered fetures will also work

Requierements

• Native USB
• Xtensa CPU
• ~4MB flash

Supported SoC's

ESP32-S3 - without changes to code/build - you can flash right away!

ESP32-S2 - with small changes to Cargo.toml and .cargo/config.toml. These changes will be discussed later in this README. Support is theoretical, not tested

Requiered peripherals

It is possible, that with changes to source code other peripherals will also work

KY-012 active buzzer (optional)
128x160 ST7735 SPI screen

Remark about screen birghtness
I have built this firmware without PWM screen brightness, so brightness is always 100%.

3D printing

This repository includes STL files for a printable case:

• sysmon.stl - main case body
• st7735s Top.stl - top cover for the ST7735 screen

Suggested wiring

ST7735 Display

Display pin	ESP32-S3 pin	Notes
VCC	3.3V	Power
GND	GND	Ground
SCL / SCK	GPIO12	SPI clock
SDA / MOSI	GPIO11	SPI data
RES / RST / RESET	GPIO2	Reset
DC / A0	GPIO7	Data/command
CS	GPIO1	Chip select
BLK / LED	3.3V	Backlight, if present

KY-012 Buzzer

Buzzer pin	ESP32-S3 pin	Notes
S	GPIO4	Signal
+ / VCC	3.3V	Power
- / GND	GND	Ground

Flashing

From release

Note: Release firmware is made only for ESP32-S3 with suggested wiring
If you want to change the firmware to suit your wiring or preferences, you should flash from source

Prerequisites:
espflash

Download latest release

Flash the firmware

espflash write-bin --chip esp32s3 0x0 display.bin

From source

Prerequisites:

Rust
espup
espflash

This repository targets ESP32-S3 and uses the esp toolchain declared in rust-toolchain.toml.

Toolchain setup

Install espup and the Espressif Rust toolchain:

cargo install espup --locked
espup install

Install espflash:

cargo install espflash

Platform-specific notes

Linux and macOS: load the environment exported by espup:

. $HOME/export-esp.sh

Host dependencies

Debian/Ubuntu:

sudo apt install llvm-dev libclang-dev clang

macOS:

brew install llvm

Running and building

Clone this repository:

git clone https://github.com/c4ff0e/esp32-sysmon-display

cd esp32-sysmon-display

This project is currently configured for ESP32-S3 in .cargo/config.toml.

Build, flash, and open the serial monitor:

cargo run --release

Build only:

cargo build --release

Build and generate release image:

cargo build --release

espflash save-image --chip esp32s3 --merge target/xtensa-esp32s3-none-elf/release/display display.bin

The release bin file will be generated at project root

If you are using different hardware and/or wiring, or have personal preferences, update the configuration in Cargo.toml, .cargo/config.toml, main.rs, frame_mgr.rs before building.

More info here

Adapting firmware to your hardware and preferences

You need to flash from source to perform these changes

Peripherals

main.rs
Display configuration:

// change frequency if you see visual artifacts
let display_config = Config::default()
    .with_frequency(Rate::from_mhz(40)) 
    .with_mode(Mode::_0);

// change GPIO pins to match your wiring
let cs = Output::new(
    peripherals.GPIO1, // here
    Level::High,
    OutputConfig::default()
);

let reset = Output::new(
    peripherals.GPIO2, // here
    Level::High,
    OutputConfig::default()
);

let dc = Output::new(
    peripherals.GPIO7, // here
    Level::Low,
    OutputConfig::default()
);
let spi_bus = Spi::new(peripherals.SPI2, display_config).unwrap()
.with_sck(peripherals.GPIO12) // here
.with_mosi(peripherals.GPIO11); // here

let rgb = true; // set to false if red and blue are swapped
let inverted = false; // set to true if colors look inverted

Buzzer configuration:

let mut beeper = Output::new(
    peripherals.GPIO4, // change this GPIO pin to match your wiring
    Level::Low,
    OutputConfig::default(),
);
// if you don't want to hear beeps at all, or you don't have a buzzer, change both values to false
const BEEP_ON_UNSUPPORTED: bool = true; // unsupported desktop hardware detected
const BEEP_ON_FAILURES: bool = true;  // server unavailable or wrong USB port

Hardware

You need to flash from source to perform these changes

To flash this firmware to ESP32-S2 change all contents of Cargo.toml to this:

[package]
edition      = "2024"
name         = "display"
rust-version = "1.88"
version      = "1.0.0"

[[bin]]
name = "display"
path = "./src/bin/main.rs"

[dependencies]
esp-hal = { version = "~1.0", features = ["esp32s2", "log-04", "unstable"] } 


esp-bootloader-esp-idf = { version = "0.4.0", features = ["esp32s2", "log-04"] }
log                    = "0.4.27"

critical-section = "1.2.0"
esp-backtrace = { version = "0.18.1", features = [
  "esp32s2",
  "panic-handler",
  "println",
] }
esp-println = { version = "0.16.1", features = ["esp32s2", "log-04"] }
usb-device = "0.3.2"
usbd-serial = "0.2.2"

postcard = {version = "1.1.3", default-features = false}
serde = { version = "1.0.188", default-features = false, features = ["derive"] }
heapless = {version = "0.9.2", features = ["serde"]}

st7735-lcd ="0.10.0"
embedded-graphics = "0.8.2"
embedded-hal-bus = "0.3.0"
profont = "0.7.0"

[profile.dev]
# Rust debug is too slow.
# For debug builds always builds with some optimization
opt-level = "s"

[profile.release]
codegen-units    = 1     # LLVM can perform better optimizations using a single thread
debug            = 2
debug-assertions = false
incremental      = false
lto              = 'fat'
opt-level        = 's'
overflow-checks  = false

and .cargo/config.toml

[target.xtensa-esp32s2-none-elf]
runner = "espflash flash --monitor --chip esp32s2"

[env]
ESP_LOG="info"

[build]
rustflags = [
  "-C", "link-arg=-nostartfiles",
]

target = "xtensa-esp32s2-none-elf"

[unstable]
build-std = ["core"]

Metrics display style

Metric panel appearance is defined in frame_mgr.rs.

You can adjust:

• CPU, GPU, and RAM border colors and enable fill
• text colors
• font styles

Example:

const CPU_TEXT_STYLE: MonoTextStyle<'_, Rgb565> =
MonoTextStyle::new(&PROFONT_12_POINT, Rgb565::CSS_STEEL_BLUE);
// you can change text color and font size

Errors/Troubleshooting

You are connected to COM port
Switch port
You have connected device to the wrong USB port, if there are two of them. Connect device to the other port.

Your [something] is unsupported
Server has reported that something from your desktop hardware is not supported by it. Display will continue to work, but unsupported hardware metrics will not be shown.

No data
Check server
Desktop server didn't send any metrics/metrics are stale. Check whether it crashed/exited/lost connection or using the wrong port.