esp-wifi

A WiFi, BLE and ESP-NOW driver for Espressif microcontrollers.

Current support

If a cell contains am em dash (—) this means that the particular feature is not present for a chip. A check mark (✓) means that some driver implementation exists. A Tilde (˜) means its implemented but buggy. An empty cell means that the feature is present in the chip but not implemented yet.

	Wifi	BLE	Coex	ESP-NOW
ESP32	✓	✓	˜	✓
ESP32-S2	✓	—	—	✓
ESP32-S3	✓	✓	✓	✓
ESP32-C3	✓	✓	✓	✓
ESP32-C2	✓	✓		✓
ESP32-C6	✓	✓		✓

Minimum supported Rust compiler version: 1.72.0.0

Usage

Importing

Ensure that the right features are enabled for your chip. See the examples for more examples.

[dependencies.esp-wifi]
# A supported chip needs to be specified, as well as specific use-case features
features = ["esp32s3", "wifi", "esp-now"]

Link configuration

Make sure to include the rom functions for your target:

# .cargo/config.toml
rustflags = [
    "-C", "link-arg=-Tlinkall.x",
    "-C", "link-arg=-Trom_functions.x",
]

At time of writing, you will already have the linkall flag if you used cargo generate. Generating from a template does not include the rom_functions flag.

Optimization Level

Link time optimization is not yet recommended for use, please ensure lto = "off" is in your Cargo.toml for both release and debug profiles.

It is necessary to build with optimization level 2 or 3 since otherwise it might not even be able to connect or advertise.

To make it work also for your debug builds add this to your Cargo.toml

[profile.dev.package.esp-wifi]
opt-level = 3

[profile.dev]
lto = "off"
[profile.release]
lto = "off"

Xtensa considerations

Within this crate, CCOMPARE0 CPU timer is used for timing, ensure that in your application you are not using this CPU timer.

USB-SERIAL-JTAG

When using USB-SERIAL-JTAG you have to activate the feature phy-enable-usb.

Don't use this feature if your are not using USB-SERIAL-JTAG since it might reduce WiFi performance.

Features

Feature	Meaning
wifi-logs	logs the WiFi logs from the driver at log level info
dump-packets	dumps packet info at log level info
utils	Provide utilities for smoltcp initialization, this is a default feature
embedded-svc	Provides a (very limited) implementation of the embedded-svc WiFi trait, includes utils feature
ble	Enable BLE support
wifi	Enable WiFi support
esp-now	Enable esp-now support
coex	Enable coex support
mtu-XXX	Set MTU to XXX, XXX can be 746, 1492, 1500, 1514. Defaults to 1492
big-heap	Reserve more heap memory for the drivers
ipv6	IPv6 support
phy-enable-usb	See USB-SERIAL-JTAG below
ps-min-modem	Enable minimum modem sleep. Only for STA mode
ps-max-modem	Enable maximum modem sleep. Only for STA mode
log	Route log output to the log crate
defmt	Add defmt::Format implementation

When using the dump-packets feature you can use the extcap in extras/esp-wifishark to analyze the frames in Wireshark. For more information see extras/esp-wifishark/README.md

Tuning

The defaults used by esp-wifi and the examples are rather conservative. It is possible to change a few of the important settings.

See Tuning for details

Examples

See Examples for details.

Missing / To be done

• Make CoEx work on ESP32 (it kind of works when commenting out setting the country in wifi_start, probably some mis-compilation since it then crashes in a totally different code path)
• Combined SoftAP/STA mode
• Support for non-open SoftAP
• Direct-boot mode isn't supported

Directory Structure

• src/timer/: systimer code used for timing and task switching
• src/preemt/: a bare minimum RISCV and Xtensa round-robin task scheduler
• src/compat/: code needed to emulate enough of an (RT)OS to use the driver
  • common.rs: basics like semaphores and recursive mutexes
  • timer_compat.rs: code to emulate timer related functionality
• examples/*.rs: examples

Driver version

This uses the WiFi drivers from https://github.com/esp-rs/esp-wireless-drivers-3rdparty

v5.1-rc2-4-gc570f67461 commit c570f674610479fc5e070c8db6d181b73ddf60a8

https://github.com/esp-rs/esp-wireless-drivers-3rdparty/ (commit 976e9cc6c0725e8325a7e3a362d113559238c45c)

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.