HD44780-AVR-library

Description:

This library is focused on providing a fast and simple way of communicating with the HD44780 controller while also providing low-level functionality to allow more control over the controller.

Note:

You can control data rate by redefining LCD_DELAY macro (default is 100)

Targets:

AVR devices

Limitations:

• Only supports 4-bit interface
• Doesn't support reading from display memory
• All pins have to be connected within a single port (PORTB, PORTD, etc..)

HD44780 LCD pinout:

Usage:

Getting started:

1. Pin configuration:

Warning: All pins have to be connected within a single port!

Create instance of PinConfig struct:

PinConfig config = {.ddr = &DDRD, .port = &PORTD, .d0 = 16, .d1 = 32, .d2 = 64, .d3 = 128, .rs = 4, .en = 8};

Values in PinConfig struct:

Assigned values must be corresponding to values of individual bits in port register:

2. Initializing the display

Call the LCD_init(PinConfig*) function with arguments:

1. pointer to an instance of the PinConfig struct

  LCD_init(&config);

Warning: If you change values in config you will also need to reinitialize the display

Display is off by default, to turn it on call LCD_on() function:

  LCD_on();

3. Printing a message:

You can prit individual characters with LCD_write_char():

  LCD_write_char('H');
  LCD_write_char('e');
  LCD_write_char('l');
  LCD_write_char('l');
  LCD_write_char('o');
  LCD_write_char(' ');
  LCD_write_char('w');
  LCD_write_char('o');
  LCD_write_char('r');
  LCD_write_char('l');
  LCD_write_char('d');
  LCD_write_char('!');

To clear the display use LCD_clear():

  LCD_clear();

To write string use LCD_write_string(char*) with arguments:

1. pointer to the string

  char greetings[] = "Hello world!";
  LCD_write_string(&greetings[0]);

4. Reference:

int LCD_init(PinConfig* config):

• Description:

  Initializes the HD44780 interface
  

• Arguments:

  1. Pointer to instance of PinConfig struct
  

• Return value: int:

  0 if success
  1 if pin verification failed (some values specified in provided config are the same or 0)
  

void LCD_instruction(uint8_t instruction):

• Description:

  Sends instruction to the display (list of instruction can be found in the datasheet on page 24)
  

• Arguments:

  1. Instruction
  

• Return value: void:

  none
  

void LCD_write_char(char character):

• Description:

  Writes one character to the display
  

• Arguments:

  1. ASCII character
  

• Return value: void:

  none
  

void LCD_clear():

• Description:

  Clears the display
  

• Arguments:

  none
  

• Return value: void:

  none
  

void LCD_set_cursor(uint8_t row, uint8_t collumn):

• Description:

  Sets the cursor position
  

• Arguments:

  1. row (0 or 1)
  2. collumn (0 to 40)
  

• Return value: void:

  none
  

void LCD_write_string(char* string):

• Description:

  Writes string of characters to the display
  

• Arguments:

  1. pointer to the string
  

• Return value: void:

  none
  

void LCD_write_buffer(char* buffer, uint16_t length):

• Description:

  Writes buffer to the display
  

• Arguments:

  1. pointer to the buffer
  2. length of the buffer
  

• Return value: void:

  none
  

void LCD_pulse_en():

• Description:

  Pulses the EN pin of the display 
    1. pulls the pin HIGH
    2. waits specified amount of microseconds (LCD_DELAY in HD44780/HD44780.h)
    3. pulls the pin LOW again
  

• Arguments:

  none
  

• Return value: void:

  none
  

void LCD_pulse_en_repeat(int repeat):

• Description:

  Calls LCD_pulse_en() specified amount of times
  

• Arguments:

  1. amount of times to repeat
  

• Return value: void:

  none
  

void LCD_show_cursor():

• Description:

  Turns on cursor on the display
  

• Arguments:

  none
  

• Return value: void:

  none
  

void LCD_hide_cusror():

• Description:

  Turns off cursor on the display
  

• Arguments:

  none
  

• Return value: void:

  none
  

void LCD_on():

• Description:

  Turns on the display
  

• Arguments:

  none
  

• Return value: void:

  none
  

void LCD_off():

• Description:

  Turns off the display
  

• Arguments:

  none
  

• Return value: void:

  none
  

void LCD_cursor_blink():

• Description:

  Turns cursor blink on
  

• Arguments:

  none
  

• Return value: void:

  none
  

void LCD_cursor_noblink():

• Description:

  Turns cursor blink off
  

• Arguments:

  none
  

• Return value: void:

  none
  

void LCD_home():

• Description:

  Sets cursor to the home position (0, 0)
  

• Arguments:

  none
  

• Return value: void:

  none
  

Resources:

• HD44780 datasheet
• Guide for communication