lcd1602.h File Reference

Header file for the LCD1602 module. More...

Go to the source code of this file.

Macros
#define	LCD1602_ADDR   0x27
#define	LCD1602_ROW_OFFSET   0x40
#define	LCD1602_DATA   0x01
#define	LCD1602_COMMAND   0x00
#define	LCD1602_CLR_E   0x00
#define	LCD1602_SET_E   0x04
#define	LCD1602_BACKLIGHT_ON   0x08
#define	LCD1602_BACKLIGHT_OFF   0x00

Functions
void	lcd1602_sendCommand (uint8_t cmd)
	Send a command. More...
void	lcd1602_sendData (uint8_t byte)
	Send a data byte. More...
void	lcd1602_init (void)
	Initialize the display. More...
void	lcd1602_displayOn (void)
	Turn the display on. More...
void	lcd1602_displayOff (void)
	Turn the display off. More...
void	lcd1602_displayClear (void)
	Clear the display. More...
void	lcd1602_cursorHome (void)
	Place the cursor at its home position. More...
void	lcd1602_cursorSet (uint8_t col, uint8_t row)
	Set cursor to the specified position. More...
void	lcd1602_putchar (const char c)
	Print a character at the display. More...
void	lcd1602_puts (const char *s)
	Print a string at the display. More...

Detailed Description

Header file for the LCD1602 module.

This is a library for the LCD1602 monochrome liquid-crystal display. The module has an i2c interface and uses a 4-bit data transfer mode where the upper 4 bits are the data and the lower 4 bits are control bits. Please see page 33 of the HD44780 data sheet for the details of the data transfer.

I2C Interface

Bit	7	6	5	4	3	2	1	0
I2C	D7	D6	D5	D4	D3	D2	D1	D0
HD7780	DB7	DB6	DB5	DB4	BL	E	R/W	RS

• DB7 ... DB4: Data bits for 4-bit operation
• BL : Background lighting (0: off, 1: on)
• E : Starts data read/write
• R/W : Selects read or write (0: write, 1: read)
• RS : Selects register (0: instruction, 1: data)

Two 4-bit transfers are necessary to send a byte to the display controller. The control bits have to be set appropriately. Look at the following code example for a possible implementation.

uint8_t backlight = LCD1602_BACKLIGHT_OFF;

static void write_4bits(uint8_t data, uint8_t rs)
{
    i2c_write(data << 4 | backlight | rs | LCD1602_SET_E);
    i2c_write(data << 4 | backlight | rs | LCD1602_CLR_E);
}

static void write_8bits(uint8_t data, uint8_t rs)
{
    write_4bits(data >> 4, rs);
    write_4bits(data, rs);
}

Author

Wolfgang Neff

Version

2.0

Date

2017-12-20

History

Created: 2013-06-19
Modified: 2016-05-14
Modified: 2017-12-20

Macro Definition Documentation

LCD1602_ADDR

#define LCD1602_ADDR   0x27

LCD1602_BACKLIGHT_OFF

#define LCD1602_BACKLIGHT_OFF   0x00

LCD1602_BACKLIGHT_ON

#define LCD1602_BACKLIGHT_ON   0x08

LCD1602_CLR_E

#define LCD1602_CLR_E   0x00

LCD1602_COMMAND

#define LCD1602_COMMAND   0x00

LCD1602_DATA

#define LCD1602_DATA   0x01

LCD1602_ROW_OFFSET

#define LCD1602_ROW_OFFSET   0x40

LCD1602_SET_E

#define LCD1602_SET_E   0x04

Function Documentation

lcd1602_cursorHome()

void lcd1602_cursorHome

(

void

)

Place the cursor at its home position.

lcd1602_cursorSet()

void lcd1602_cursorSet	(	uint8_t	col,
		uint8_t	row
	)

Set cursor to the specified position.

This routine places the cursor at the specified position. The column and row counting starts with 1.

Parameters

col	The new column position.
row	The new row position.

lcd1602_displayClear()

void lcd1602_displayClear

(

void

)

Clear the display.

Clears the display and sets the cursor to its home position.

lcd1602_displayOff()

void lcd1602_displayOff

(

void

)

Turn the display off.

Turns the display and the background lighting off.

lcd1602_displayOn()

void lcd1602_displayOn

(

void

)

Turn the display on.

Turns the display and the background lighting on.

lcd1602_init()

void lcd1602_init

(

void

)

Initialize the display.

This routine initializes the I2C module and the display controller. Please see page 46 of the HD44780 data sheet for the details.

lcd1602_putchar()

void lcd1602_putchar

(

const char

c

)

Print a character at the display.

Parameters

c	The character to be printed.

lcd1602_puts()

void lcd1602_puts

(

const char *

s

)

Print a string at the display.

Parameters

s	The string to be printed.

lcd1602_sendCommand()

void lcd1602_sendCommand

(

uint8_t

cmd

)

Send a command.

Sends a command to the display controller by an I2C transaction.

Parameters

cmd	The command to be sent.

lcd1602_sendData()

void lcd1602_sendData

(

uint8_t

byte

)

Send a data byte.

Sends a data byte to the display controller by an I2C transaction.

Parameters

data	The data byte to be sent.