This is a peripheral driver library for interfacing stm32 microcontrollers with the HD44780 display driver. The implementation uses the stm32 HAL to maximise device compatibility.

Features

Pure C implementation.
Only depends on the stm32 HAL include file.
4 bit and 8 bit operation.
5x8 dots and 5x10 dots symbol generation.
Accurate software delays.

Installation

This library is meant to be used in projects that employ the stm32 HAL library. The easiest way to include the library in your project is to simply copy HD44780.h to your include directory and HD44780.c to your source directory. The aforementioned files can be downloaded from the releases page.

Configuration

Before starting to use the library you are going to need to select your target architecture. This is done by defining a corresponding preprocessor symbol. The possible architectures are listed below:

STM32F0
STM32F1
STM32F2
STM32F3
STM32F4
STM32F7
STM32H7
STM32G0
STM32G4
STM32L0
STM32L1
STM32L4
STM32L5
STM32WB
STM32WL

Here are a couple of ways to define one of these symbols:

Define a symbol in your preprocessor settings

One method is to define the chosen symbol globally using the preprocessor settings.

With GCC:

gcc -DSTM32XX [options] [source files] [-o output file]

With STM32CubeIDE 1.7:

Project -> Properties -> C/C++ General -> Paths and Symbols -> Symbols -> Add...

Create an HD44780_config.h file

If none of the architecture symbols are defined the library will look for the HD44780_config.h file in your include path. This file can be used for defining the symbol for the chosen architecture. A template for this file can be obtained from the releases page.

#define STM32F1

API documentation

Documentation for the latest version is available at https://murar8.github.io/stm32-HD44780/latest

If you want to read the documentation for a specific version you can append the version tag to the base url. Example: https://murar8.github.io/stm32-HD44780/v0.1.0

Usage examples

Some common usage scenarios are listed below.

Initialization, 4 bit mode, 2 lines, 5x8 character font

HD44780 lcd = {
    .rs_gpio = LCD_RS_GPIO_Port,
    .rw_gpio = LCD_RW_GPIO_Port,
    .en_gpio = LCD_EN_GPIO_Port,
    .d4_gpio = LCD_D4_GPIO_Port,
    .d5_gpio = LCD_D5_GPIO_Port,
    .d6_gpio = LCD_D6_GPIO_Port,
    .d7_gpio = LCD_D7_GPIO_Port,
    .rs_pin = LCD_RS_Pin,
    .rw_pin = LCD_RW_Pin,
    .en_pin = LCD_EN_Pin,
    .d4_pin = LCD_D4_Pin,
    .d5_pin = LCD_D5_Pin,
    .d6_pin = LCD_D6_Pin,
    .d7_pin = LCD_D7_Pin,
};
 
HD44780_init(&lcd);

Initialization, 8 bit mode, single line, 5x10 character font

HD44780 lcd = {
    .rs_gpio = LCD_RS_GPIO_Port,
    .rw_gpio = LCD_RW_GPIO_Port,
    .en_gpio = LCD_EN_GPIO_Port,
    .d0_gpio = LCD_D0_GPIO_Port,
    .d1_gpio = LCD_D1_GPIO_Port,
    .d2_gpio = LCD_D2_GPIO_Port,
    .d3_gpio = LCD_D3_GPIO_Port,
    .d4_gpio = LCD_D4_GPIO_Port,
    .d5_gpio = LCD_D5_GPIO_Port,
    .d6_gpio = LCD_D6_GPIO_Port,
    .d7_gpio = LCD_D7_GPIO_Port,
    .rs_pin = LCD_RS_Pin,
    .rw_pin = LCD_RW_Pin,
    .en_pin = LCD_EN_Pin,
    .d0_pin = LCD_D0_Pin,
    .d1_pin = LCD_D1_Pin,
    .d2_pin = LCD_D2_Pin,
    .d3_pin = LCD_D3_Pin,
    .d4_pin = LCD_D4_Pin,
    .d5_pin = LCD_D5_Pin,
    .d6_pin = LCD_D6_Pin,
    .d7_pin = LCD_D7_Pin,
    .interface_8_bit = true,
    .single_line = true,
    .font_5x10 = true,
};
 
HD44780_init(&lcd);

Printing a string on the lcd

HD44780_put_str(&lcd, "Hello, world!");

HD44780_put_str

void HD44780_put_str(const HD44780 *lcd, const char *str)

Write a string to the lcd, then advance the cursor.

Generating and printing a new 5x8 symbol

uint8_t skull[8] = {
    0b00000,
    0b01110,
    0b10001,
    0b11011,
    0b10001,
    0b01110,
    0b01110,
    0b00000
};
 
HD44780_create_symbol(&lcd, 0x04, false, skull);
HD44780_put_str(&lcd, "\x04");

Enable cursor and blinking

HD44780_Config lcd_config = { .enable_cursor = true, .enable_blink = true };

HD44780_configure(&lcd, &lcd_config);

HD44780_configure

void HD44780_configure(const HD44780 *lcd, const HD44780_Config *config)

Update the configuration of the controller.

HD44780_Config

HD44780 controller configuration.

Definition: HD44780.h:113

HD44780_Config::enable_cursor

bool enable_cursor

Make the cursor visible.

Definition: HD44780.h:124

Update the text in a specific position

HD44780_put_str(&lcd, "Temperature: 21C");
HD44780_cursor_to(&lcd, 13, 0);
HD44780_put_str(&lcd, "30");

Donations

I do not expect to make any money from this project but if you would like to buy me a coffee or something you are welcome to do so :)

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.