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 16000000
Definition for LCD controller type
Use 0 for HD44780 controller, change to 1 for displays with KS0073 controller.
#define	LCD_CONTROLLER_KS0073 0
Definitions for Display Size
Change these definitions to adapt setting to your display
#define	LCD_LINES 2
#define	LCD_DISP_LENGTH 20
#define	LCD_LINE_LENGTH 0x40
#define	LCD_START_LINE1 0x00
#define	LCD_START_LINE2 0x40
#define	LCD_START_LINE3 0x14
#define	LCD_START_LINE4 0x54
#define	LCD_WRAP_LINES 0
#define	LCD_IO_MODE 1
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
#define	LCD_DATA0_PORT LCD_PORT
#define	LCD_DATA1_PORT LCD_PORT
#define	LCD_DATA2_PORT LCD_PORT
#define	LCD_DATA3_PORT LCD_PORT
#define	LCD_DATA0_PIN 3
#define	LCD_DATA1_PIN 2
#define	LCD_DATA2_PIN 1
#define	LCD_DATA3_PIN 0
#define	LCD_RS_PORT LCD_PORT
#define	LCD_RS_PIN 7
#define	LCD_RW_PORT LCD_PORT
#define	LCD_RW_PIN 5
#define	LCD_E_PORT LCD_PORT
#define	LCD_E_PIN 6
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.

Define Documentation

#define LCD_BUSY 7

#define LCD_CGRAM 6

#define LCD_CLR 0

#define LCD_CONTROLLER_KS0073 0

Use 0 for HD44780 controller, 1 for KS0073 controller

#define LCD_DATA0_PIN 3

pin for 4bit data bit 0

#define LCD_DATA0_PORT LCD_PORT

port for 4bit data bit 0

#define LCD_DATA1_PIN 2

pin for 4bit data bit 1

#define LCD_DATA1_PORT LCD_PORT

port for 4bit data bit 1

#define LCD_DATA2_PIN 1

pin for 4bit data bit 2

#define LCD_DATA2_PORT LCD_PORT

port for 4bit data bit 2

#define LCD_DATA3_PIN 0

pin for 4bit data bit 3

#define LCD_DATA3_PORT LCD_PORT

port for 4bit data bit 3

#define LCD_DDRAM 7

#define LCD_DISP_LENGTH 20

visibles characters per line of the display

#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_E_PIN 6

pin for Enable line

#define LCD_E_PORT LCD_PORT

port for Enable line

#define LCD_ENTRY_DEC 0x04

#define LCD_ENTRY_DEC_SHIFT 0x05

#define LCD_ENTRY_INC 1

#define LCD_ENTRY_INC_ 0x06

#define LCD_ENTRY_INC_SHIFT 0x07

#define LCD_ENTRY_MODE 2

#define LCD_ENTRY_SHIFT 0

#define LCD_FUNCTION 5

#define LCD_FUNCTION_10DOTS 2

#define LCD_FUNCTION_2LINES 3

#define LCD_FUNCTION_4BIT_1LINE 0x20

#define LCD_FUNCTION_4BIT_2LINES 0x28

#define LCD_FUNCTION_8BIT 4

#define LCD_FUNCTION_8BIT_1LINE 0x30

#define LCD_FUNCTION_8BIT_2LINES 0x38

#define LCD_HOME 1

#define LCD_IO_MODE 1

0: memory mapped mode, 1: IO port mode

#define LCD_LINE_LENGTH 0x40

internal line length of the display

#define LCD_LINES 2

number of visible lines of the display

#define LCD_MODE_DEFAULT ((1<<LCD_ENTRY_MODE) | (1<<LCD_ENTRY_INC) )

#define LCD_MOVE 4

#define LCD_MOVE_CURSOR_LEFT 0x10

#define LCD_MOVE_CURSOR_RIGHT 0x14

#define LCD_MOVE_DISP 3

#define LCD_MOVE_DISP_LEFT 0x18

#define LCD_MOVE_DISP_RIGHT 0x1C

#define LCD_MOVE_RIGHT 2

#define LCD_ON 3

#define LCD_ON_BLINK 0

#define LCD_ON_CURSOR 1

#define LCD_ON_DISPLAY 2

#define LCD_PORT PORTB

port for the LCD lines

#define lcd_puts_P ( __s ) lcd_puts_p(PSTR(__s))

macros for automatically storing string constant in program memory

#define LCD_RS_PIN 7

pin for RS line

#define LCD_RS_PORT LCD_PORT

port for RS line

#define LCD_RW_PIN 5

pin for RW line

#define LCD_RW_PORT LCD_PORT

port for RW line

#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 XTAL 16000000

clock frequency in Hz, used to calculate delay timer

Function Documentation

void lcd_clrscr ( void )

Clear display and set cursor to home position.

Parameters:

void

Returns:: none

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

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:

character to be displayed

Returns:: none

void lcd_puts ( const char * s )

Display string without auto linefeed.

Parameters:

string to be displayed

Returns:: none

void lcd_puts_p ( const char * progmem_s )

Display string from program memory without auto linefeed.

Parameters:

string from program memory be be displayed

Returns:: none

See also:: lcd_puts_P

Generated on Sat Jun 9 13:19:03 2007 for Automatisk Guitartuner by

1.5.2

LCD library

Functions

Definitions for MCU Clock Frequency

Definition for LCD controller type

Definitions for Display Size

Definitions for 4-bit IO mode

Definitions for LCD command instructions

Detailed Description

Define Documentation

Function Documentation