hd44780-driver

Implementation of the embedded-hal traits for the HD44780.

Examples

Examples for several different boards can be found here

Any platform that implements the embedded-hal traits is supported by this library! See awesome-embedded-rust for a list of supported platforms.

Getting Started

This library aims to keep it simple in that to get started all you will have to do is supply the HD44780::new function a bunch of pins from your platform that implement the OutputPin trait for embedded-hal as well as a struct that implements the delay traits DelayUs<u16> and DelayMs<u8>.

// Pseudo-code: check the HAL crate for your specific device for exact code to get pins / delay
// It is recommended to use push/pull output pins, but if your specific LCD device has pull-up resistors
// an open/drain output pin should work too

let mut delay = Delay::new();

let mut lcd = HD44780::new_4bit(
    d4.into_push_pull_output(&mut port), // Register Select pin
    d3.into_push_pull_output(&mut port), // Enable pin

    d9.into_push_pull_output(&mut port),  // d4
    d10.into_push_pull_output(&mut port), // d5
    d11.into_push_pull_output(&mut port), // d6
    d12.into_push_pull_output(&mut port), // d7
    &mut delay,
);

// Unshift display and set cursor to 0
lcd.reset(&mut delay);

// Clear existing characters
lcd.clear(&mut delay);

// Display the following string
lcd.write_str("Hello, world!", &mut delay);

// Move the cursor to the second line
lcd.set_cursor_pos(40, &mut delay);

// Display the following string on the second line
lcd.write_str("I'm on line 2!", &mut delay);

Async API

The async API is similar to the sync API. The the major differences are that:

The async API requires the async feature to use.
The async API requires the nightly compiler because of use of unstable features.
The async API uses embedded-hal-async rather than embedded-hal traits.

Embassy provides some implementations of these traits for some MCUs, and provides an executor that can execute futures. However, projects implementing embedded-hal-async traits, including this project, can run on any executor with any driver, provided such executor and driver also implement embedded-async-traits.

use hd44780_driver::non_blocking::HD44780;

let mut delay = embassy::time::Delay::new();
pin_mut!(delay);

let mut display = HD44780::new_4bit(
    rs,
    en,
    d4,
    d5,
    d6,
    d7,
    delay.as_mut(),
)
.await
.unwrap();

display.clear(delay.as_mut()).await;
display.write_str(msg, delay.as_mut()).await;

Features

4-bit & 8-bit modes are supported
Support for i2c backpacks
Non-blocking API

Todo

Busy flag support
A more user-friendly API with additional features
Custom characters

Contributing

Additional issues as well as pull-requests are welcome.
If you have a platform not yet covered in this repository that is supported by embedded-hal, a pull-request of an example would be awesome!

License

This project is licensed under MIT license (LICENSE or https://opensource.org/licenses/MIT)

ahmedcharles/hd44780-driver