Hello World

There is a lot to learn, so let's start simple. Our "hello world" is more of a logging practice.

Connect the board to your computer and access the first project:
```
cd exercises/hello_world
```
Build, flash, and monitor the project with cargo run. You should see:
```
..
Commands:
    CTRL+R    Reset chip
    CTRL+C    Exit
..
loop..!
..
```
Tip

Try pressing CTRL+R to reset, then press CTRL+C to exit.

The aim here is just run the binary.

Build, flash and monitor?

The .cargo/config.toml includes this config:

[target.riscv32imac-unknown-none-elf] # our processor arch.
runner = "espflash flash --monitor"   # for `cargo run`.

Our cargo run is replaced by cargo build && espflash flash <elf_path> --monitor.

This builds and then flashes the binary. Finally, it monitors for logs. Removing --monitor it won't wait for logs.

We already know our code can print information with println! macro. For prettier logs we can use log or defmt. Let's try adding them:

Take some time to read the code. Do you recognise the boilerplate discussed earlier?
Try commenting out the line:
```
use esp_backtrace as _;
```
So that we can see what it provides. Then uncomment the line.
Uncomment the "log lines" in src/main.rs,
Add the log dependency to Cargo.toml.
The log crate logging level is controlled with ESP_LOG under the [env] section in .cargo/config.toml.
- Change the ESP_LOG variable to turn off all logs. Re-run cargo run, to test how it works.
- Try with other levels, for example, with trace.

The examples/hello_world.rs contains a solution. You can run it with cargo run --example hello_world.

Important

Running the solution requires fixing the log-lines at the bottom of Cargo.toml.