LCD16x2-4bits-Driver-AVR

LCD 16x2 interfacing with AVR Atmega16a microcontroller using 4-bits mode - LCD16x2 4bits Mode Driver

Description:

A driver for alphanumeric characters LCD 16x2 modules with the internal HD-44780U controller using 4-bits mode.

Target microcontrollers:

This library uses only I/O ports & registers, so it can be used for all 8-bits AVRs family microcontrollers and some other simple 8-bits microcontrollers by editing the I/O ports & registers definitions macros in lcd.h file.

Features:

Use 4-bits mode for minimum microcontroller pins usage (uses only 7 port pins).
Allow the user to select which microcontroller port pins to connect the while LCD pins.
Tested and verified with the Smallest delay for this slow LCD modules (as the biggest delay for commands/data never exceeds 2ms).
Contains all the LCD HD44780U controller possible functions from clear, shifting, cursor modes .. etc.

Functions Supported:

initializing LCD.
send commands to LCD.
send single character data to LCD.
send a string to LCD.
clear LCD.
set cursor mode (on, off, blinking).
shift the cursor to right and left.
shift displayed data to right and left.
move the DDRAM address of LCD to any position.

Requirements:

compiled for AVR/GNU C Compiler (avr-gcc) for 8 bits AVR micro-controllers

How to use:

All LCD configurations related to I/O interfacing are placed in lcd.h file

Change the I/O registers to the LCD port you want to use in lcd

#define LCD_DATA_DDR		DDRA						// LCD data/command port direction register		
#define LCD_DATA_PORT		PORTA						// LCD data/command port register
#define LCD_DATA_PIN		PINA						// LCD data/command pin register	
#define LCD_CONTROL_DDR		DDRB						// LCD control port direction register	
#define LCD_CONTROL_PORT	PORTB						// LCD control port register	
#define RS										0		// LCD RS pin
#define RW										1		// LCD R/W pin
#define EN										2		// LCD EN pin

The library is compiled for a specific LCD D4-D7 pins connection to microcontroller pins by using pre-compiled user-defined macros as follows:

Use this code if you connect LCD D4-D7 pins to microcontroller port pins 0-3

#define USE_MCU_PORT_HIGH_OR_LOW_NIBBLE			0		// 0>use port 0,1,2,3 pins .. 1>use port 4,5,6,7 pins
#define LCD_D4_PIN								0		// make it 0 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 0 .. 4 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 1
#define LCD_D5_PIN								1		// make it 1 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 0 .. 5 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 1
#define LCD_D6_PIN								2		// make it 2 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 0 .. 6 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 1
#define LCD_D7_PIN								3		// make it 3 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 0 .. 7 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 1

OR edit to this code instead if you connect LCD D4-D7 pins to microcontroller port pins 4-7

#define USE_MCU_PORT_HIGH_OR_LOW_NIBBLE			1		// 0>use port 0,1,2,3 pins .. 1>use port 4,5,6,7 pins
#define LCD_D4_PIN								4		// make it 0 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 0 .. 4 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 1
#define LCD_D5_PIN								5		// make it 1 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 0 .. 5 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 1
#define LCD_D6_PIN								6		// make it 2 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 0 .. 6 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 1
#define LCD_D7_PIN								7		// make it 3 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 0 .. 7 if USE_MCU_PORT_HIGH_OR_LOW_NIBBLE = 1

Testing and verification:

All functions have been tested and verified on AVR Atmega16a microcontroller.

Demo:

"youtube link"

NOTE:

Files: lcd.h and lcd.c are the only files for the driver.
File: main.c is for driver testing and verification.

amr-mostafa/LCD16x2-4bits-Driver-AVR