I2C based PCF8574 access library for HD44780 based LCD on Raspberry Pi using pigpio for I2C access
Copyright U. Raich Jan. 2017
This program is part of a course on embedded systems held at the University of Cape Coast, Ghana in 2017
It is released under the GNU Public License For details please see https://www.gnu.org/licenses/gpl.html. More...

#include <hd44780.h>

Include dependency graph for hd44780.c:

Functions
void	hd44780SetDebug (bool onOff)
	switches debug mode on or off More...

int	hd44780BackLight (bool onOff)
	switches the display back light on or off More...

int	hd44780Home ()
	Sets the DDRAM address to zero such that the next character is written to the top left position if the LED screen. If the display is shifted it is set back to the original position. More...

int	hd44780Cursor (bool onOff, bool blink)
	Sets the DDRAM address to zero such that the next character is written to the top left position if the LED screen. If the display is shifted it is set back to the original position. More...

int	hd44780Display (bool onOff)
	Switches the display on or off. More...

int	hd44780EntryMode (bool incDec, bool shift)
	Defines if the address counter counts up or down and sets shifting the whole display on or off. More...

int	hd44780SecondLine ()
	Sets the DDRAM address to the beginning of the second line. More...

int	hd44780SetDDRamAddr (unsigned char addr)
	Sets the DDRAM address. More...

int	hd44780Clear ()
	Clears the display. More...

int	hd44780PutC (char c)
	Write a character to the display. More...

int	hd44780PutS (char *text)
	Writes a zero terminated character string to the display Not more than 16 characters are written it no zero is found. More...

int	hd44780ReadBusy (bool busy, unsigned char address)
	Reads the busy flag and the DDRAM address. More...

int	hd44780GetC (char *c)
	Read a character from the display. More...

int	hd44780Open ()
	hd44770Open: initializes the pigpio library opens the I2C connection to the pcf8574 which is on the I2C address 0x3f More...

void	hd44780Close ()
	hd44770Close: closes the I2C connection to the pcf8574 and disconnects from the pigpio library More...

int	hd44780CreateChar (unsigned char cgramAddr, unsigned char *dotMatrix)
	hd44780CreateChar: creates a character in the character generator RAM (CGRAM) More...

Detailed Description

I2C based PCF8574 access library for HD44780 based LCD on Raspberry Pi using pigpio for I2C access
Copyright U. Raich Jan. 2017
This program is part of a course on embedded systems held at the University of Cape Coast, Ghana in 2017
It is released under the GNU Public License For details please see https://www.gnu.org/licenses/gpl.html.

:

Author: Uli Raich

Function Documentation

◆ hd44780BackLight()

int hd44780BackLight ( bool onOff )

switches the display back light on or off

Parameters

onOff true: switches debug mode on
false: switches debug mode off

Returns: result from the call to the pigpio library

Return values

HD44780_SUCCESS	-> success
negative	error code from the pigpio library

◆ hd44780Clear()

int hd44780Clear ( void )

Clears the display.

Returns: result from the call to the hd44780WriteCmd function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780WriteCmd function

◆ hd44780Close()

void hd44780Close ( void )

hd44770Close: closes the I2C connection to the pcf8574 and disconnects from the pigpio library

◆ hd44780CreateChar()

int hd44780CreateChar	(	unsigned char	cgramAddr,
		unsigned char *	dotMatrix
	)

hd44780CreateChar: creates a character in the character generator RAM (CGRAM)

Parameters

address	the address in the CGRAM where to write the character must be on a 8 byte boundary
character	the dot matrix consisting of 7 bytes

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780putC function

◆ hd44780Cursor()

int hd44780Cursor	(	bool	onOff,
		bool	blink
	)

Sets the DDRAM address to zero such that the next character is written to the top left position if the LED screen. If the display is shifted it is set back to the original position.

Returns: result from the call to the hd44780WriteCmd function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780WriteCmd function

◆ hd44780Display()

int hd44780Display ( bool onOff )

Switches the display on or off.

Parameters

onOff false: switches the display off
true: switches it on

Returns: result from the call to the hd44780WriteCmd function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780WriteCmd function

◆ hd44780EntryMode()

int hd44780EntryMode	(	bool	incDec,
		bool	shift
	)

Defines if the address counter counts up or down
and sets shifting the whole display on or off.

Parameters

incDec	false: the address counter is decremented when a character is written true: it is incremented
shift	false: display shifts are switched off true: they are switched on

Returns: result from the call to the hd44780WriteCmd function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780WriteCmd function

◆ hd44780GetC()

int hd44780GetC ( char * c )

Read a character from the display.

Parameters

c	pointer to the character read from the display controller

Returns: result from the call to the hd44780Read function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780Read function

◆ hd44780Home()

int hd44780Home ( void )

Sets the DDRAM address to zero such that the next character is written to the top left position if the LED screen. If the display is shifted it is set back to the original position.

Returns: result from the call to the hd44780WriteCmd function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780WriteCmd function

◆ hd44780Open()

int hd44780Open ( void )

hd44770Open: initializes the pigpio library opens the I2C connection to the pcf8574 which is on the I2C address 0x3f

Returns: result from the call to the pigpio library

Return values

HD44780_SUCCESS	-> success
negative	error code from the pigpio library

◆ hd44780PutC()

int hd44780PutC ( char c )

Write a character to the display.

Parameters

c	the character to be written

Returns: result from the call to the hd44780WriteCmd function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780WriteCmd function

◆ hd44780PutS()

int hd44780PutS ( char * text )

Writes a zero terminated character string to the display Not more than 16 characters are written it no zero is found.

Parameters

text	the zero terminated C character string

Returns: result from the call to the hd44780PutC function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780PutC function

◆ hd44780ReadBusy()

int hd44780ReadBusy	(	bool *	busy,
		unsigned char *	address
	)

Reads the busy flag and the DDRAM address.

Parameters

*busy	a pointer to a boolean into which the busy flag will be written
*address	a pointer to an unsigned char into which the DDRAM address will be written

Returns: result from the call to the hd44780Read function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780Read function

◆ hd44780SecondLine()

int hd44780SecondLine ( void )

Sets the DDRAM address to the beginning of the second line.

Returns: result from the call to hd44780SetDDRamAddr()

◆ hd44780SetDDRamAddr()

int hd44780SetDDRamAddr ( unsigned char addr )

Sets the DDRAM address.

Parameters

addr	the DDRAM address to which the next character will be written or read from

Returns: result from the call to the hd44780WriteCmd function

Return values

HD44780_SUCCESS	-> success
negative	error code from the hd44780WriteCmd function

◆ hd44780SetDebug()

void hd44780SetDebug ( bool onOff )

switches debug mode on or off

Parameters

onOff true: switches debug mode on
false: switches debug mode off

Functions

Detailed Description

Function Documentation

◆ hd44780BackLight()

◆ hd44780Clear()

◆ hd44780Close()

◆ hd44780CreateChar()

◆ hd44780Cursor()

◆ hd44780Display()

◆ hd44780EntryMode()

◆ hd44780GetC()

◆ hd44780Home()

◆ hd44780Open()

◆ hd44780PutC()

◆ hd44780PutS()

◆ hd44780ReadBusy()

◆ hd44780SecondLine()

◆ hd44780SetDDRamAddr()

◆ hd44780SetDebug()