i2c1602

A Raspberry Pi C library to write LCD 16x2 with I2C using WiringPi

This library is based mainly on Lewis Loflin's code. It uses wiringPi I2C to interface with an I2C 16x2 LCD, which has a I2C converter module attached in the back.

To clone and install this library:

Make sure to have wiringPi installed. RasbianOS has wiringPi pre-installed by default. Check by typing gpio -v in terminal. If there is a version then wiringPi is installed.

$ wget https://github.com/vinhcatba/i2c1602/archive/refs/heads/main.zip
$ unzip main.zip
$ cd i2c1602-main
$ make
$ sudo make install

To use: include lib and declare I2C16x2 struct

include <i2c1602.h>
I2C16x2 lcd;

compile your program with -lwiringPi -li2c1602 flags.

$ gcc -lwiringPi -li2c1602 -o example example.c

for more details see example.c and source + header file.

Usage and API

void lcd_init(int addr);

initialize LCD at addr I2C address. Address can be found by typing i2cdetect -y 1 to terminal. this function will set data length to 4-bit, 2 line, small font size, display ON, cursor OFF, cursor blink OFF, direction Left to Right and clear the display screen + RAM.

void lcd_setAddr(int fd);

this function set/change LCD I2C address, without init.

address stores in (int)addr inside struct I2C16x2

void lcd_byte(int bits, int mode);

send a byte of data, using 4-bit lenght (send 2 nibble). Mode can be LCD_CMD for command or LCD_CHR for character.

void lcd_toggle_enable(int bits);

toggle Enable bit after sending a nibble (4 bits)

void typeInt(int i);

print integer as a string to LCD at current cursor position

void typeFloat(float myFloat);

print float with 2 digits after decimal point as a string to LCD at current cursor position

void typeString(const char *s);

print string of any length to lcd (no text wrapping)

void typeChar(char val);

print a char to current cursor position.

void lcdLoc(int line);

move cursor to position line. Position is LINE1/LINE2 + offset. Example: lcdLoc(LINE1) to move cursor to LINE 1 ROW 0 LINE 1; lcdLoc(LINE2+7) move to LINE 2 ROW 7

void ClrLcd(void);

clear LCD display + RAM and return cursor to home (LINE 1 ROW 0 or 0x80)