qmk-firmware/docs/feature_hd44780.md
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Co-Authored-By: fauxpark <fauxpark@gmail.com>
2019-10-18 18:14:49 -07:00

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Markdown

# HD44780 LCD Displays
This is an integration of Peter Fleury's LCD library. This page will explain the basics. [For in depth documentation visit his page.](http://homepage.hispeed.ch/peterfleury/doxygen/avr-gcc-libraries/group__pfleury__lcd.html)
You can enable support for HD44780 Displays by setting the `HD44780_ENABLE` flag in your keyboards `rules.mk` to yes.
## Configuration
You will need to configure the pins used by your display, and its number of lines and columns in your keyboard's `config.h`.
Uncomment the section labled HD44780 and change the parameters as needed.
````
/*
* HD44780 LCD Display Configuration
*/
#define LCD_LINES 2 //< number of visible lines of the display
#define LCD_DISP_LENGTH 16 //< visibles characters per line of the display
#define LCD_IO_MODE 1 //< 0: memory mapped mode, 1: IO port mode
#if LCD_IO_MODE
#define LCD_PORT PORTB //< port for the LCD lines
#define LCD_DATA0_PORT LCD_PORT //< port for 4bit data bit 0
#define LCD_DATA1_PORT LCD_PORT //< port for 4bit data bit 1
#define LCD_DATA2_PORT LCD_PORT //< port for 4bit data bit 2
#define LCD_DATA3_PORT LCD_PORT //< port for 4bit data bit 3
#define LCD_DATA0_PIN 4 //< pin for 4bit data bit 0
#define LCD_DATA1_PIN 5 //< pin for 4bit data bit 1
#define LCD_DATA2_PIN 6 //< pin for 4bit data bit 2
#define LCD_DATA3_PIN 7 //< pin for 4bit data bit 3
#define LCD_RS_PORT LCD_PORT //< port for RS line
#define LCD_RS_PIN 3 //< pin for RS line
#define LCD_RW_PORT LCD_PORT //< port for RW line
#define LCD_RW_PIN 2 //< pin for RW line
#define LCD_E_PORT LCD_PORT //< port for Enable line
#define LCD_E_PIN 1 //< pin for Enable line
#endif
````
Should you need to configure other properties you can copy them from `quantum/hd44780.h` and set them in your `config.h`
## Usage
To initialize your display, call `lcd_init()` with one of these parameters:
````
LCD_DISP_OFF : display off
LCD_DISP_ON : display on, cursor off
LCD_DISP_ON_CURSOR : display on, cursor on
LCD_DISP_ON_CURSOR_BLINK : display on, cursor on flashing
````
This is best done in your keyboards `matrix_init_kb` or your keymaps `matrix_init_user`.
It is advised to clear the display before use.
To do so call `lcd_clrsrc()`.
To now print something to your Display you first call `lcd_gotoxy(column, line)`. To go to the start of the first line you would call `lcd_gotoxy(0, 0)` and then print a string with `lcd_puts("example string")`.
There are more methods available to control the display. [For in depth documentation please visit the linked page.](http://homepage.hispeed.ch/peterfleury/doxygen/avr-gcc-libraries/group__pfleury__lcd.html)