esp-println

Provides print!, println! and dbg! implementations for various Espressif devices.

• Supports ESP32, ESP32-C2/C3/C6, ESP32-H2, ESP32-S2/S3, and ESP8266
• Dependency free (not even depending on esp-hal, one optional dependency is log, another is critical-section)
• Supports JTAG-Serial output where available
• Supports RTT (lacking working RTT hosts besides probe-rs for ESP32-C3)
• no-op features turns printing into a no-op

RTT on ESP32-C3 / ESP32-C6

The cli utility should work for flashing and showing RTT logs on ESP32-C3 by using it's run command. You need to use the direct-boot feature of the HAL to flash via probe-rs.

Usage

In your Cargo.toml, under [dependencies], add:

esp-println = { version = "0.3.1", features = ["esp32"] }

Choose a recent version and your chipset.

Then in your program:

use esp_println::println;

You can now println!("Hello world") as usual.

Logging

With the feature log activated you can initialize a simple logger like this

init_logger(log::LevelFilter::Info);

There is a default feature colors which enables colored log output.

Additionally you can use

init_logger_from_env();

In this case the following environment variables are used:

• ESP_LOGLEVEL sets the log level, use values like trace, info etc.
• ESP_LOGTARGETS if set you should provide the crate names of crates (optionally with a path e.g. esp_wifi::compat::common) which should get logged, separated by , and no additional whitespace between

If this simple logger implementation isn't sufficient for your needs you can implement your own logger on top of esp-println - see https://docs.rs/log/0.4.17/log/#implementing-a-logger

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.