Tutorial.LCD8Bits History

Hide minor edits - Show changes to output

November 22, 2008, at 06:32 PM by David A. Mellis -
Added lines 1-2:
(:redirect Reference/LiquidCrystal :)
October 18, 2005, at 02:00 AM by 195.178.229.25 -
Changed lines 1-121 from:
http://static.flickr.com/25/53544993_3611fce234_o.jpg
to:
!!LCD Display - 8 bits

This example shows the most basic action to be done with a LCD display: to show a welcome message. In our case we have an LCD display with backlight and contrast control. Therefore we will use a potentiometer to regulate the contrast.

LCD displays are most of the times driven using an industrial standard established by Hitachi. According to it there is a group of pins dedicated to sending data and locations of that data on the screen, the user can choose to use 4 or 8 pins to send data. On top of that three more pins are needed to synchronize the communication towards the display.

The backdrop of this example is that we are using almost all the available pins on Arduino board in order to drive the display, but we have decided to show it this way for simplicity.

[[http://static.flickr.com/25/53544993_3611fce234_o.jpg|http://static.flickr.com/25/53544993_3611fce234.jpg]]

''Picture of a protoboard supporting the display and a potentiometer''

[=
/* LCD Hola
* --------
*
* This is the first example in how to use an LCD screen
* configured with data transfers over 8 bits. The example
* uses all the digital pins on the Arduino board, but can
* easily display data on the display
*
* There are the following pins to be considered:
*
* - DI, RW, DB0..DB7, Enable (11 in total)
*
* the pinout for LCD displays is standard and there is plenty
* of documentation to be found on the internet.
*
* (cleft) 2005 DojoDave for K3
*
*/

int DI = 12;
int RW = 11;
int DB[] = {3, 4, 5, 6, 7, 8, 9, 10};
int Enable = 2;

void LcdCommandWrite(int value) {
// poll all the pins
int i = 0;
for (i=DB[0]; i <= DI; i++) {
digitalWrite(i,value & 01);
value >>= 1;
}
digitalWrite(Enable,LOW);
delayMicroseconds(1);
// send a pulse to enable
digitalWrite(Enable,HIGH);
delayMicroseconds(1); // pause 1 ms according to datasheet
digitalWrite(Enable,LOW);
delayMicroseconds(1); // pause 1 ms according to datasheet
}

void LcdDataWrite(int value) {
// poll all the pins
int i = 0;
digitalWrite(DI, HIGH);
digitalWrite(RW, LOW);
for (i=DB[0]; i <= DB[7]; i++) {
digitalWrite(i,value & 01);
value >>= 1;
}
digitalWrite(Enable,LOW);
delayMicroseconds(1);
// send a pulse to enable
digitalWrite(Enable,HIGH);
delayMicroseconds(1);
digitalWrite(Enable,LOW);
delayMicroseconds(1); // pause 1 ms according to datasheet
}

void setup (void) {
int i = 0;
for (i=Enable; i <= DI; i++) {
pinMode(i,OUTPUT);
}
delay(100);
// initiatize lcd after a short pause
// needed by the LCDs controller
LcdCommandWrite(0x30); // function set:
// 8-bit interface, 1 display lines, 5x7 font
delay(64);
LcdCommandWrite(0x30); // function set:
// 8-bit interface, 1 display lines, 5x7 font
delay(50);
LcdCommandWrite(0x30); // function set:
// 8-bit interface, 1 display lines, 5x7 font
delay(20);
LcdCommandWrite(0x06); // entry mode set:
// increment automatically, no display shift
delay(20);
LcdCommandWrite(0x0E); // display control:
// turn display on, cursor on, no blinking
delay(20);
LcdCommandWrite(0x01); // clear display, set cursor position to zero
delay(100);
LcdCommandWrite(0x80); // display control:
// turn display on, cursor on, no blinking
delay(20);
}

void loop (void) {
LcdCommandWrite(0x02); // set cursor position to zero
delay(10);
// Write the welcome message
LcdDataWrite('H');
LcdDataWrite('o');
LcdDataWrite('l');
LcdDataWrite('a');
LcdDataWrite(' ');
LcdDataWrite('C');
LcdDataWrite('a');
LcdDataWrite('r');
LcdDataWrite('a');
LcdDataWrite('c');
LcdDataWrite('o');
LcdDataWrite('l');
LcdDataWrite('a');
delay(500);
}
=]
October 18, 2005, at 01:53 AM by 195.178.229.25 -
Added line 1:
http://static.flickr.com/25/53544993_3611fce234_o.jpg

Share