AVR-GCC 4 bit and 8 bit LCD library
Standard alphanumeric LCD display controlled by 74HC164 LCD controller can accept 8 bit data bytes or 4 bit nibbles. Earlier my 4 bit and 8 bit LCD libraries were split in separate files as they were used in different projects. Now they are merged in to one library where simple logic is implemented to select 4 bit or 8 bit library just by modifying only three lines of code.
In the library header file there is line added:
//Uncomment this if LCD 4 bit interface isused
//******************************************
#define LCD_4bit
//******************************************
what allows to select different LCD modes by commenting and uncommenting this line. Also don't forget to select proper ports and pins where LCD is connected:
#define LCD_RS 0 //define MCU pin connected to LCD RS
#define LCD_RW 1 //define MCU pin connected to LCD R/W
#define LCD_E 2 //define MCU pin connected to LCD E
#define LCD_D0 0 //define MCU pin connected to LCD D0
#define LCD_D1 1 //define MCU pin connected to LCD D1
#define LCD_D2 2 //define MCU pin connected to LCD D1
#define LCD_D3 3 //define MCU pin connected to LCD D2
#define LCD_D4 4 //define MCU pin connected to LCD D3
#define LCD_D5 5 //define MCU pin connected to LCD D4
#define LCD_D6 6 //define MCU pin connected to LCD D5
#define LCD_D7 7 //define MCU pin connected to LCD D6
#define LDP PORTD //define MCU port connected to LCD data pins
#define LCP PORTD //define MCU port connected to LCD control pins
#define LDDR DDRD //define MCU direction register for port connected to LCD data pins
#define LCDR DDRD //define MCU direction register for port connected to LCD control pins
In newer library there is also couple new functionalities added:
-
Predefining 8 custom LCD characters during LCD initialisation;
-
LCDprogressBar() function have been adapted from AVRLib.
Complete function set:
void LCDsendChar(uint8_t); //forms data ready to send to 74HC164
void LCDsendCommand(uint8_t); //forms data ready to send to 74HC164
void LCDinit(void); //Initializes LCD
void LCDclr(void); //Clears LCD
void LCDhome(void); //LCD cursor home
void LCDstring(uint8_t*, uint8_t); //Outputs string to LCD
void LCDGotoXY(uint8_t, uint8_t); //Cursor to X Y position
void CopyStringtoLCD(const uint8_t*, uint8_t, uint8_t);//copies flash string to LCD at x,y
void LCDdefinechar(const uint8_t *,uint8_t);//write char to LCD CGRAM
void LCDshiftRight(uint8_t); //shift by n characters Right
void LCDshiftLeft(uint8_t); //shift by n characters Left
void LCDcursorOn(void); //Underline cursor ON
void LCDcursorOnBlink(void); //Underline blinking cursor ON
void LCDcursorOFF(void); //Cursor OFF
void LCDblank(void); //LCD blank but not cleared
void LCDvisible(void); //LCD visible
void LCDcursorLeft(uint8_t); //Shift cursor left by n
void LCDcursorRight(uint8_t); //shif cursor right by n
// displays a horizontal progress bar at the current cursor location
void LCDprogressBar(uint8_t progress, uint8_t maxprogress, uint8_t length);
I have added simple demo program that should help to start working with LCD:

Comments
Changing PORT
How can I change the port to conect the lcd screen?I mean, I m using an ATmega16 MCU and I want to use The PORTC instead of PORTD.I tried changing the header file lcd_lib.hwriting:#define LDP PORTC #define LCP PORTC #define LDDR DDRC #define LCDR DDRC But guess what nothing happens still working on PORTDor your library only works in PORTD??
Blinking LEDs
I wish that more topics will be included on Blinking LEDs
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