Microcontrollers

The cortex_m_rt crate provides (among other things) a reset handler for Cortex M microcontrollers.

1. ```
   #![no_main]
   ```
2. ```
   #![no_std]
   ```

4. ```
   extern crate panic_halt as _;
   ```

6. ```
   mod interrupts;
   ```

8. ```
   use cortex_m_rt::entry;
   ```

10. ```
    #[entry]
    ```
11. ```
    fn main() -> ! {
    ```
12. ```
        loop {}
    ```
13. ```
    }
    ```

Next we’ll look at how to access peripherals, with increasing levels of abstraction.

• The cortex_m_rt::entry macro requires that the function have type fn() -> !, because returning to the reset handler doesn’t make sense.
• Run the example with cargo embed --bin minimal