4 releases (2 breaking)

0.4.0 Sep 15, 2020
0.3.0 Feb 21, 2019
0.2.1 Oct 17, 2018
0.2.0 Aug 8, 2018

#40 in Embedded development

Download history 19/week @ 2020-06-02 5/week @ 2020-06-09 6/week @ 2020-06-16 2/week @ 2020-06-23 5/week @ 2020-06-30 6/week @ 2020-07-07 9/week @ 2020-07-14 3/week @ 2020-07-21 5/week @ 2020-07-28 5/week @ 2020-08-04 20/week @ 2020-08-11 39/week @ 2020-08-18 31/week @ 2020-08-25 12/week @ 2020-09-01 12/week @ 2020-09-08 19/week @ 2020-09-15

56 downloads per month
Used in nucleo-f401re

MIT license

776 lines


crates.io crates.io travis-ci.org API

Implementation of the embedded-hal traits for the HD44780.


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);


  • 4-bit & 8-bit modes are supported
  • Support for i2c backpacks


  • Busy flag support (Waiting for support from embedded-hal to read and write from a pin)
  • Non-blocking API
  • A more user-friendly API with additional features
  • Custom characters


  • 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!


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