# uart_16550
[](https://github.com/rust-osdev/uart_16550/actions?query=workflow%3ABuild) [](https://docs.rs/uart_16550/)
Minimal support for [serial communication](https://en.wikipedia.org/wiki/Asynchronous_serial_communication) through [UART](https://en.wikipedia.org/wiki/Universal_asynchronous_receiver-transmitter) devices, which are compatible to the [16550 UART](https://en.wikipedia.org/wiki/16550_UART). This crate supports port-mapped and memory mapped UARTS.
## Usage
Depending on the system architecture, the UART can be either accessed through [port-mapped I/O](https://wiki.osdev.org/Port_IO) or [memory-mapped I/O](https://en.wikipedia.org/wiki/Memory-mapped_I/O).
### With port-mappd I/O
The UART is accessed through port-mapped I/O on architectures such as `x86_64`. On these architectures, the [`SerialPort`](https://docs.rs/uart_16550/~0.2/uart_16550/struct.SerialPort.html) type can be used:
```rust
use uart_16550::SerialPort;
const SERIAL_IO_PORT: u16 = 0x3F8;
let mut serial_port = unsafe { SerialPort::new(SERIAL_IO_PORT) };
serial_port.init();
// Now the serial port is ready to be used. To send a byte:
serial_port.send(42);
// To receive a byte:
let data = serial_port.receive();
```
### With memory mapped serial port
Most other architectures, such as [RISC-V](https://en.wikipedia.org/wiki/RISC-V), use memory-mapped I/O for accessing the UARTs. On these architectures, the [`MmioSerialPort`](https://docs.rs/uart_16550/~0.2/uart_16550/struct.MmioSerialPort.html) type can be used:
```rust
use uart_16550::MmioSerialPort;
const SERIAL_PORT_BASE_ADDRESS: usize = 0x1000_0000;
let mut serial_port = unsafe { MmioSerialPort::new(SERIAL_PORT_BASE_ADDRESS) };
serial_port.init();
// Now the serial port is ready to be used. To send a byte:
serial_port.send(42);
// To receive a byte:
let data = serial_port.receive();
```
## Crate Feature Flags
* `nightly`: This is the default.
* `stable`: Use this to build with non-nightly rust. Needs `default-features = false`.
## Building with stable rust
This needs to have the [compile-time requirements](https://github.com/alexcrichton/cc-rs#compile-time-requirements) of the `cc` crate installed on your system.
It was currently only tested on Linux and MacOS.
## License
Licensed under the MIT license ([LICENSE](LICENSE) or <http://opensource.org/licenses/MIT>).