# Runnging the Program from VS Code

Both `cargo-embed` and `cargo-flash` are tools based on the `probe-rs` library. This library exposes an API to communicate with the J-Link and perform all the operations exposed by the JTAG protocol. For this workshop we have developed a small Cargo runner that uses the `probe-rs` library to streamline the process of running a program and printing logs, like `cargo-embed`, while also having better integration into VS code.

1. Run this command from the `tools/dk-run` folder:

``` console
$ cargo install --path . -f
```

2. Open the `src/bin/hello.rs` file and click the "Run" button that's hovering over the `main` function.

Note: you will get the "Run" button if the Rust analyzer's workspace is set to the `beginner/apps` folder. This will be the case if the current folder in VS code (left side panel) is set to `beginner/apps`.

If you are not using VS code, run the command `cargo run --bin hello` from within the `beginer/apps` folder. Rust Analyzer's "Run" button is a short-cut for that command.

``` console
$ cargo run --bin hello
INFO:hello -- Hello, world!
stack backtrace:
   0: 0x0000229c - __bkpt
   1: 0x0000030e - hello::__cortex_m_rt_main
   2: 0x0000011a - main
   3: 0x00001ba2 - Reset
```

`cargo run` will compile the application and then invoke the `dk-run` tool with its argument set to the path of the output ELF file.

Unlike `cargo-embed`, `dk-run` will terminate when the program reaches a breakpoint (`asm::bkpt`) that halts the device. Before exiting `dk-run` will print a stack backtrace of the program starting from the breakpoint. This can be used to write small test programs that are meant to perform some work and then terminate.