LCD library

Basic routines for interfacing a HD44780U-based text LCD display. More...

Functions
void	lcd_init (uint8_t dispAttr)
	Initialize display and select type of cursor.
void	lcd_clrscr (void)
	Clear display and set cursor to home position.
void	lcd_home (void)
	Set cursor to home position.
void	lcd_gotoxy (uint8_t x, uint8_t y)
	Set cursor to specified position.
void	lcd_putc (char c)
	Display character at current cursor position.
void	lcd_puts (const char *s)
	Display string without auto linefeed.
void	lcd_puts_p (const char *progmem_s)
	Display string from program memory without auto linefeed.
void	lcd_command (uint8_t cmd)
	Send LCD controller instruction command.
void	lcd_data (uint8_t data)
	Send data byte to LCD controller.
#define	lcd_puts_P(__s)   lcd_puts_p(PSTR(__s))
	macros for automatically storing string constant in program memory
Definitions for MCU Clock Frequency
Adapt the MCU clock frequency in Hz to your target.
#define	XTAL   F_CPU
	clock frequency in Hz, used to calculate delay timer
Definition for LCD controller type
Use 0 for HD44780 controller, change to 1 for displays with KS0073 controller.
#define	LCD_CONTROLLER_KS0073   0
	Use 0 for HD44780 controller, 1 for KS0073 controller.
Definitions for Display Size
Change these definitions to adapt setting to your display
#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_LINE_LENGTH   0x40
	internal line length of the display
#define	LCD_START_LINE1   0x00
	DDRAM address of first char of line 1.
#define	LCD_START_LINE2   0x40
	DDRAM address of first char of line 2.
#define	LCD_START_LINE3   0x14
	DDRAM address of first char of line 3.
#define	LCD_START_LINE4   0x54
	DDRAM address of first char of line 4.
#define	LCD_WRAP_LINES   0
	0: no wrap, 1: wrap at end of visibile line
#define	LCD_IO_MODE   1
	0: memory mapped mode, 1: IO port mode
Definitions for 4-bit IO mode
Change LCD_PORT if you want to use a different port for the LCD pins. The four LCD data lines and the three control lines RS, RW, E can be on the same port or on different ports. Change LCD_RS_PORT, LCD_RW_PORT, LCD_E_PORT if you want the control lines on different ports. Normally the four data lines should be mapped to bit 0..3 on one port, but it is possible to connect these data lines in different order or even on different ports by adapting the LCD_DATAx_PORT and LCD_DATAx_PIN definitions.
#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   0
	pin for 4bit data bit 0
#define	LCD_DATA1_PIN   1
	pin for 4bit data bit 1
#define	LCD_DATA2_PIN   2
	pin for 4bit data bit 2
#define	LCD_DATA3_PIN   3
	pin for 4bit data bit 3
#define	LCD_RS_PORT   PORTD
	port for RS line
#define	LCD_RS_PIN   2
	pin for RS line
#define	LCD_RW_PORT   PORTD
	port for RW line
#define	LCD_RW_PIN   3
	pin for RW line
#define	LCD_E_PORT   PORTD
	port for Enable line
#define	LCD_E_PIN   4
	pin for Enable line
Definitions for LCD command instructions
The constants define the various LCD controller instructions which can be passed to the function lcd_command(), see HD44780 data sheet for a complete description.
#define	LCD_CLR   0
#define	LCD_HOME   1
#define	LCD_ENTRY_MODE   2
#define	LCD_ENTRY_INC   1
#define	LCD_ENTRY_SHIFT   0
#define	LCD_ON   3
#define	LCD_ON_DISPLAY   2
#define	LCD_ON_CURSOR   1
#define	LCD_ON_BLINK   0
#define	LCD_MOVE   4
#define	LCD_MOVE_DISP   3
#define	LCD_MOVE_RIGHT   2
#define	LCD_FUNCTION   5
#define	LCD_FUNCTION_8BIT   4
#define	LCD_FUNCTION_2LINES   3
#define	LCD_FUNCTION_10DOTS   2
#define	LCD_CGRAM   6
#define	LCD_DDRAM   7
#define	LCD_BUSY   7
#define	LCD_ENTRY_DEC   0x04
#define	LCD_ENTRY_DEC_SHIFT   0x05
#define	LCD_ENTRY_INC_   0x06
#define	LCD_ENTRY_INC_SHIFT   0x07
#define	LCD_DISP_OFF   0x08
#define	LCD_DISP_ON   0x0C
#define	LCD_DISP_ON_BLINK   0x0D
#define	LCD_DISP_ON_CURSOR   0x0E
#define	LCD_DISP_ON_CURSOR_BLINK   0x0F
#define	LCD_MOVE_CURSOR_LEFT   0x10
#define	LCD_MOVE_CURSOR_RIGHT   0x14
#define	LCD_MOVE_DISP_LEFT   0x18
#define	LCD_MOVE_DISP_RIGHT   0x1C
#define	LCD_FUNCTION_4BIT_1LINE   0x20
#define	LCD_FUNCTION_4BIT_2LINES   0x28
#define	LCD_FUNCTION_8BIT_1LINE   0x30
#define	LCD_FUNCTION_8BIT_2LINES   0x38
#define	LCD_MODE_DEFAULT   ((1<<LCD_ENTRY_MODE) | (1<<LCD_ENTRY_INC) )

---

Detailed Description

Basic routines for interfacing a HD44780U-based text LCD display.

 #include <lcd.h> 

Originally based on Volker Oth's LCD library, changed lcd_init(), added additional constants for lcd_command(), added 4-bit I/O mode, improved and optimized code.

Library can be operated in memory mapped mode (LCD_IO_MODE=0) or in 4-bit IO port mode (LCD_IO_MODE=1). 8-bit IO port mode not supported.

Memory mapped mode compatible with Kanda STK200, but supports also generation of R/W signal through A8 address line.

Author:

Peter Fleury pfleury@gmx.ch http://jump.to/fleury

See also:

The chapter Interfacing a HD44780 Based LCD to an AVR on my home page.

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Function Documentation

void lcd_clrscr

(

void

)

Clear display and set cursor to home position.

Parameters:

void

Returns:

none

Referenced by lcd_init().

void lcd_command

(

uint8_t

cmd )

Send LCD controller instruction command.

Parameters:

cmd	instruction to send to LCD controller, see HD44780 data sheet

Returns:

none

Referenced by lcd_clrscr(), lcd_gotoxy(), lcd_home(), and lcd_init().

void lcd_data

(

uint8_t

data )

Send data byte to LCD controller.

Similar to lcd_putc(), but without interpreting LF

Parameters:

data	byte to send to LCD controller, see HD44780 data sheet

Returns:

none

void lcd_gotoxy	(	uint8_t	x,
		uint8_t	y
	)

Set cursor to specified position.

Parameters:

x	horizontal position (0: left most position)
y	vertical position (0: first line)

Returns:

none

void lcd_home

(

void

)

Set cursor to home position.

Parameters:

void

Returns:

none

void lcd_init

(

uint8_t

dispAttr )

Initialize display and select type of cursor.

Parameters:

dispAttr

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

Returns:

none

void lcd_putc

(

char

c )

Display character at current cursor position.

Parameters:

c	character to be displayed

Returns:

none

Referenced by lcd_puts(), and lcd_puts_p().

void lcd_puts

(

const char *

s )

Display string without auto linefeed.

Parameters:

s	string to be displayed

Returns:

none

void lcd_puts_p

(

const char *

progmem_s )

Display string from program memory without auto linefeed.

Parameters:

s	string from program memory be be displayed

Returns:

none

See also:

lcd_puts_P