1. Interfacing to LCD 16x2
By hendri@eepis-its.edu

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3. Block Diagram

4. Pin Connection

5. Timing Diagram

6. Timing Diagram

7. LCD Command

8. LCD Command

9. Initialize Procedure

10. Arduino way
#include <LiquidCrystal.h>
//LiquidCrystal lcd(RS, EN, D4, D5, D6, D7);
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
void setup() {
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print("H");
}
void loop() {
}

11. Arduino From Scratch
int RS = 8; delay(5); //delay 4.1ms
int En = 9;
int D4 = 4; //function set 1
int D5 = 5; digitalWrite(RS,LOW);
int D6 =6; digitalWrite(D7,LOW);
int D7 =7 ; digitalWrite(D6,LOW);
digitalWrite(D5,HIGH);
void enable() digitalWrite(D4,HIGH);
{ enable();
digitalWrite(En,LOW);
delay(1); delayMicroseconds(100);
digitalWrite(En,HIGH);
delay(1); //function set 1
digitalWrite(En,LOW); digitalWrite(RS,LOW);
} digitalWrite(D7,LOW);
// the setup routine runs once when you press reset: digitalWrite(D6,LOW);
void setup() { digitalWrite(D5,HIGH);
// initialize the digital pin as an output. digitalWrite(D4,HIGH);
pinMode(RS, OUTPUT); enable();
pinMode(En, OUTPUT);
pinMode(D4, OUTPUT); //bf can be check after following instruction
pinMode(D5, OUTPUT); digitalWrite(RS,LOW);
pinMode(D6, OUTPUT); digitalWrite(D7,LOW);
pinMode(D7, OUTPUT); digitalWrite(D6,LOW);
digitalWrite(D5,HIGH);
delay(15); digitalWrite(D4,LOW);
enable();
//function set 1
digitalWrite(RS,LOW);
digitalWrite(D7,LOW);
digitalWrite(D6,LOW);
digitalWrite(D5,HIGH);
digitalWrite(D4,HIGH);
enable();

12. Arduino From Cont
//function set 4 bit //display clear
digitalWrite(RS,LOW); digitalWrite(RS,LOW);
digitalWrite(D7,LOW); digitalWrite(D7,LOW);
digitalWrite(D6,LOW); digitalWrite(D6,LOW);
digitalWrite(D5,HIGH); digitalWrite(D5,LOW);
digitalWrite(D4,LOW); digitalWrite(D4,LOW);
enable(); enable();
digitalWrite(RS,LOW); digitalWrite(RS,LOW);
digitalWrite(D7,HIGH); digitalWrite(D7,LOW);
enable(); digitalWrite(D6,LOW);
digitalWrite(D5,LOW);
//display off digitalWrite(D4,HIGH);
digitalWrite(RS,LOW); enable();
digitalWrite(D7,LOW);
digitalWrite(D6,LOW); //entry mode set
digitalWrite(D5,LOW); digitalWrite(RS,LOW);
digitalWrite(D4,LOW); digitalWrite(D7,LOW);
enable(); digitalWrite(D6,LOW);
digitalWrite(RS,LOW); digitalWrite(D5,LOW);
digitalWrite(D7,HIGH); digitalWrite(D4,LOW);
digitalWrite(D6,LOW); enable();
digitalWrite(D5,LOW); digitalWrite(RS,LOW);
digitalWrite(D4,LOW); digitalWrite(D7,LOW);
enable(); digitalWrite(D6,LOW);
digitalWrite(D5,HIGH);
digitalWrite(D4,HIGH);
enable();
// init done

13. Arduino From Cont
// display on // the loop routine runs over and over again forever:
digitalWrite(RS,LOW); void loop() {
digitalWrite(D7,LOW); }
digitalWrite(D6,LOW);
digitalWrite(D5,LOW);
digitalWrite(D4,LOW);
enable();
digitalWrite(RS,LOW);
digitalWrite(D7,HIGH);
digitalWrite(D6,HIGH);
digitalWrite(D5,HIGH);
digitalWrite(D4,LOW);
enable();
// display 'H'
digitalWrite(RS,HIGH);
digitalWrite(D7,LOW);
digitalWrite(D6,HIGH);
digitalWrite(D5,LOW);
digitalWrite(D4,LOW);
enable();
digitalWrite(RS,HIGH);
digitalWrite(D7,HIGH);
digitalWrite(D6,LOW);
digitalWrite(D5,LOW);
digitalWrite(D4,LOW);
enable();
}