Happy Chinese New Year

Arduino with 4x20 LCD using LCD4bit libaray

How to use LCD4bit with Arduino and LCD


















1. for Duemilanove board, use NG with ATmega168 instead of Diecimila in Arduino IDE 0012


2. Arduino------LCD------LCD pin

----------2--------enable---- 6

----------7--------DB4-------11

----------8--------DB5-------12

----------9--------DB6-------13

----------10------DB7-------14

----------12------DI (RS)----4

---------GND----RW---------5

3. Need to modify LCD4bit.cpp (\arduino-0012\hardware\libaries\LCD4Bit\LCD4bit.cpp) as follows and delete LCD4bit.o before compile/ verify the sketch.

I changed the origenal 4bit library code myself to let it work with my 4x20LCD, KS0066u Based.
I got it working perfectly.
Below the code for those of you who have the same LCD.

LCD4Bit.cpp:
changes I made
just replace the origenal ones with this ones.

The new constructor:

LCD4Bit::LCD4Bit (int num_lines) {
g_num_lines = num_lines;
if (g_num_lines < g_num_lines =" 1;"> 4)
{
g_num_lines = 4;
}
}

function cursorTo

void LCD4Bit::cursorTo(int line_num, int x){
//first, put cursor home
commandWrite(CMD_HOME);
if (x>19)
{
x=19;
}
switch (line_num)
{
case 1:
x+=0x00 ; break;
case 2:
x+= 0x40 ; break;
case 3:
x+= 0x14 ; break; // In fact, line 3 is an extension of the line 1 (beyond the 20 first characters)
case 4:
x+= 0x54 ; break; // Line 4 is an extension of line 2
}
//
commandWrite(0x80+x);
}

Test program:

#include
LCD4Bit lcd = LCD4Bit(4);

void setup() {
pinMode(13, OUTPUT); //we'll use the debug LED to output a heartbeat
lcd.init();
}

void loop() {
digitalWrite(13, HIGH); //light the debug LED
lcd.clear();
lcd.cursorTo(1,0);
lcd.printIn("Line 1");
lcd.cursorTo(2,0);
lcd.printIn("Line 2");
lcd.cursorTo(3,0);
lcd.printIn("Line 3");
lcd.cursorTo(4,0);
lcd.printIn("Line 4");
delay(1000);
digitalWrite(13, LOW); //clear the debug LED
}

Hope it works for you to!

check www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1170601618/0