//! Serial interface echo server
//!
//! In this example every received byte will be sent back to the sender. You can test this example
//! with serial terminal emulator like `minicom`.
//!
//! ```
//! #![deny(unsafe_code)]
//! #![deny(warnings)]
//! #![no_main]
//! #![no_std]
//! 
//! #[macro_use(entry, exception)]
//! extern crate cortex_m_rt as rt;
//! extern crate f4;
//! #[macro_use(block)]
//! extern crate nb;
//! extern crate panic_semihosting;
//! 
//! use f4::hal::prelude::*;
//! use f4::hal::serial::Serial;
//! use f4::hal::stm32f4;
//! use rt::ExceptionFrame;
//! 
//! entry!(main);
//! 
//! fn main() -> ! {
//!     let p = stm32f4::Peripherals::take().unwrap();
//! 
//!     let mut flash = p.FLASH.constrain();
//!     let mut rcc = p.RCC.constrain();
//!     let mut gpioa = p.GPIOA.split(&mut rcc.ahb);
//! 
//!     let clocks = rcc.cfgr.freeze(&mut flash.acr);
//! 
//!     let tx = gpioa.pa9.into_af7(&mut gpioa.moder, &mut gpioa.afrh);
//!     let rx = gpioa.pa10.into_af7(&mut gpioa.moder, &mut gpioa.afrh);
//! 
//!     let serial = Serial::usart1(p.USART1, (tx, rx), 115_200.bps(), clocks, &mut rcc.apb2);
//!     let (mut tx, mut rx) = serial.split();
//! 
//!     loop {
//!         let byte = block!(rx.read()).unwrap();
//!         block!(tx.write(byte)).ok();
//!     }
//! }
//! 
//! exception!(HardFault, hard_fault);
//! 
//! fn hard_fault(ef: &ExceptionFrame) -> ! {
//!     panic!("{:#?}", ef);
//! }
//! 
//! exception!(*, default_handler);
//! 
//! fn default_handler(irqn: i16) {
//!     panic!("Unhandled exception (IRQn = {})", irqn);
//! }
//! ```
// Auto-generated. Do not modify.
