Lesson 22 – 1602 LCD

Setup

1. Before you start working with any of the tutorials in this series please make sure you have completed the following tasks –
   1. Downloaded and installed the Arduino IDE.
   2. Are able to connect to the Arduino IDE from your computer
   3. Have been successful in uploading a simple (e.g. Blink LED’s) example programs (that comes with the Arduino IDE) onto your Arduino UNO board
2. If you haven’t installed the Arduino IDE please head back to the first tutorial and make sure you’ve gone through each of the steps involved.
3. Once you’ve sorted all of the above you are ready to move onto the next tutorial.

Tutorial

In this experiment, we use an Arduino to drive the 1602 LCD. 1602 LCD has wide applications. In the beginning,1602 LCD uses a HD44780 controller. Now, almost all 1602 LCD module uses a compatible IC, but their features are basically the same.

1602LCD Parameters:

1. Display Capacity: 16 × 2 characters
2. Chip Operating Voltage: 4.5 ~ 5.5V
3. Working Current: 2.0mA (5.0V)
4. Optimum working voltage of the module is 5.0V
5. Character Size: 2.95 * 4.35 (W * H) mm

LCD 1602 Interface Description:

1. Two power sources, one for module power, another one for backlight, generally use 5V. In this project, we use 3.3V for backlight.
2. VL is the pin for adjusting contrast ratio; it usually connects a potentiometer(no more than 5KΩ) in series for its adjustment. In this experiment, we use a 1KΩ resistor. For the connection, it has 2 methods, namely high potential and low potential. Here, we use low potential method; connect the resistor and then the GND.
3. RS is a very common pin in LCD. It’s a selecting pin for command/data. When the pin is in high level, it’s in data mode; when it’s in low level, it’s in command mode.
4. RW pin is also very common in LCD. It’s a selecting pin for read/write. When the pin is in high level, it’s in read operation; when it’s in low level, it’s in write operation.
5. E pin is also very common in LCD. Usually, when the signal in the bus is stabilized, it sends out a positive pulse requiring read operation. When this pin is in high level, the bus is not allowed to have any change.
6. D0-D7 is 8-bit bidirectional parallel bus, used for command and data transmission.
7. BLA is anode for back light; BLK, cathode for back light.

1602 can directly communicate with Arduino. According to the product manual, it has two connection methods, namely 8-bit connection and 4-bit connection.

Hardware Required : Here’s the hardware you will need for the tutorials –

1. Arduino Board x1
2. 1 * 1602 LCD
3. 1 * Breadboard
4. 1 * potentiometer
5. 1 * USB cable
6. 16 *Jumper wires

8-bit connection method:

Connection:

You will find fritzing diagrams below outlining circuit connections for both the Arduino Uno and the Arduino Mega 2560.

Let’s have a look at the code for the tutorial.

int DI = 12;
int RW = 11;
int DB[] = {3, 4, 5, 6, 7, 8, 9, 10};// use array to select pin for bus
int Enable = 2;

void LcdCommandWrite(int value) {
// define all pins
int i = 0;
for (i=DB[0]; i <= DI; i++) // assign value for bus { digitalWrite(i,value & 01);// for 1602 LCD, it uses D7-D0( not D0-D7) for signal identification; here, it’s used for signal inversion. value >>= 1;
}
digitalWrite(Enable,LOW);
delayMicroseconds(1);
digitalWrite(Enable,HIGH);
delayMicroseconds(1);  // wait for 1ms
digitalWrite(Enable,LOW);
delayMicroseconds(1);  // wait for 1ms
}

void LcdDataWrite(int value) {
// initialize all 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);
digitalWrite(Enable,HIGH);
delayMicroseconds(1);
digitalWrite(Enable,LOW);
delayMicroseconds(1);  // wait for 1ms
}

void setup (void) {
int i = 0;
for (i=Enable; i <= DI; i++) {
   pinMode(i,OUTPUT);
}
delay(100);
// initialize LCD after a brief pause
// for LCD control
LcdCommandWrite(0x38);  // select as 8-bit interface, 2-line display, 5x7 character size 
delay(64);                      
LcdCommandWrite(0x38);  // select as 8-bit interface, 2-line display, 5x7 character size 
delay(50);                      
LcdCommandWrite(0x38);  // select as 8-bit interface, 2-line display, 5x7 character size             
delay(20);                      
LcdCommandWrite(0x06);  // set input mode
                         // auto-increment, no display of shifting
delay(20);                      
LcdCommandWrite(0x0E);  // display setup
                         // turn on the monitor, cursor on, no flickering
delay(20);                      
LcdCommandWrite(0x01);  // clear the scree, cursor position returns to 0
delay(100);                      
LcdCommandWrite(0x80);  //  display setup
                         //  turn on the monitor, cursor on, no flickering

delay(20);                      
}

void loop (void) {
  LcdCommandWrite(0x01);  // clear the scree, cursor position returns to 0  
  delay(10); 
  LcdCommandWrite(0x80+3); 
  delay(10);                     
  // write in welcome message 
  LcdDataWrite('W');
  LcdDataWrite('e');
  LcdDataWrite('l');
  LcdDataWrite('c');
  LcdDataWrite('o');
  LcdDataWrite('m');

  LcdDataWrite('e');
  LcdDataWrite(' ');
  LcdDataWrite('t');
  LcdDataWrite('o');
  delay(10);
  LcdCommandWrite(0xc0+1);  // set cursor position at second line, second position
  delay(10); 
  LcdDataWrite('g');
  LcdDataWrite('e');
  LcdDataWrite('e');
  LcdDataWrite('k');
  LcdDataWrite('-');
  LcdDataWrite('w');
  LcdDataWrite('o');
  LcdDataWrite('r');
  LcdDataWrite('k');
  LcdDataWrite('s');
  LcdDataWrite('h');
  LcdDataWrite('o');
  LcdDataWrite('p');
  delay(5000);
  LcdCommandWrite(0x01);  // clear the screen, cursor returns to 0  
  delay(10);
  LcdDataWrite('I');
  LcdDataWrite(' ');
  LcdDataWrite('a');
  LcdDataWrite('m');
  LcdDataWrite(' ');
  LcdDataWrite('h');
  LcdDataWrite('o');
  LcdDataWrite('n');
  LcdDataWrite('g');
  LcdDataWrite('y');
  LcdDataWrite('i');
  delay(3000);
  LcdCommandWrite(0x02); // set mode as new characters replay old ones, where there is no new ones remain the same
  delay(10);
  LcdCommandWrite(0x80+5); // set cursor position at first line, sixth position
  delay(10);  

  LcdDataWrite('t');
  LcdDataWrite('h');
  LcdDataWrite('e');
  LcdDataWrite(' ');
  LcdDataWrite('a');
  LcdDataWrite('d');
  LcdDataWrite('m');
  LcdDataWrite('i');
  LcdDataWrite('n');
  delay(5000);
}

4-bit connection method: When using this module, 8-bit connection uses all the digital pins of the Arduino, leaving no pin for sensors. What then? you can use 4-bit connection.

See the diagrams below for connections for the Arduino Uno and Arduino Mega 2560.

Please Note : The line of code with the #include is incomplete. It should read,

#include <LiquidCrystal.h>

Please make the change in your program before you try compiling it.

/*
  LiquidCrystal Library - Hello World

 Demonstrates the use a 16x2 LCD display.  The LiquidCrystal
 library works with all LCD displays that are compatible with the
 Hitachi HD44780 driver. There are many of them out there, and you
 can usually tell them by the 16-pin interface.

 This sketch prints "Hello World!" to the LCD
 and shows the time.

  The circuit:
 * LCD RS pin to digital pin 12
 * LCD Enable pin to digital pin 11
 * LCD D4 pin to digital pin 9
 * LCD D5 pin to digital pin 8
 * LCD D6 pin to digital pin 7
 * LCD D7 pin to digital pin 6
 * LCD R/W pin to ground
 * LCD VSS pin to ground
 * LCD VCC pin to 5V
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)

 Library originally added 18 Apr 2008
 by David A. Mellis
 library modified 5 Jul 2009
 by Limor Fried (http://www.ladyada.net)
 example added 9 Jul 2009
 by Tom Igoe
 modified 22 Nov 2010
 by Tom Igoe

 This example code is in the public domain.

 http://www.arduino.cc/en/Tutorial/LiquidCrystal
 */

// include the library code: 
#include 

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 9, 8, 7, 6);

void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print("hello, world!");
}

void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(millis() / 1000);
}

Download the above code to the controller board and see the result.

Prerequisites

This development track requires an investment a bit of hardware. See below for details –

1. Arduino IDE –
   1. You will need to download and install the Arduino development IDE.
   2. The approach to installation, configuration, setup of the Arduino IDE is covered in our tutorials.
2. Arduino Uno, Sensors, etc. –
   1. You will need to purchase the Super Learning Kit for Arduino from OzToyLib.
   2. The Arduino Advent kit has all the sensors you need to perform the tutorials covered in this development track.
   3. If you do not have an Arduino Uno or Arduino Mega 2560 you might want to head over to Arduino boards and pick one up now.

The Super Learning Kit for the Arduino kit has all the sensors you need to perform the tutorials covered in this development track.

About the Super Learning Kit for Arduino

The Super Learning Starter Kit for Arduino comes packed with ~35+ different electronic bits (Sensors, LEDs, switches, LCD, servo, etc.) and can be purchased with either the Keyestudio UNO R3 or the Keyestudio Mega 2560 board. The Keyestudio Arduino boards can be used to interface with the different electronic bits i.e. sensors, LED’s, switches, servos, etc. included in the starter kit. The starter kit for the Keyestudio Uno R3 offers a great opportunity to explore the world of electronics using the Arduino Development Platform. Interact with the real world through the various sensors, create innovative projects, learn how to program the micro:bit to read data from the sensors and perform certain actions. The starter kit for the Arduino is a great way to dive into the awesome world of electronics and get started with your own STEM (Science, Technology, Engineering, Math) learning journey.

The Arduino advanced study kit walks you through the basics of using the Arduino in a hands-on way. You’ll learn the fundamentals of electronics and working on the Arduino through building several creative projects. The kit includes a selection of the most common and useful electronic components with a book of 32 projects. Starting the basics of electronics, to more complex projects, the kit will get you interacting with the physical world using sensor and actuators. Along with the kit you get access to detailed tutorials and wiring diagrams.

You can purchase the Super Learning Kit for Arduino from OzToyLib.

About the Arduino UNO

The Arduino UNO is the most used and documented board of the whole Arduino family and very easy to setup, play with. The Arduino UNO is a microcontroller board based on the ATmega328 . The Arduino UNO has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button. Here’s a listing of the some of the features of the Arduino UNO –

1. Microcontroller: ATmega328
2. Operating Voltage: 5V
3. Input Voltage (recommended): 7-12V
4. Input Voltage (limits): 6-20V
5. Digital I/O Pins: 14 (of which 6 provide PWM output)
6. Analog Input Pins: 6
7. DC Current per I/O Pin: 40 mA
8. DC Current for 3.3V Pin: 50 mA
9. Flash Memory: 32 KB of which 0.5 KB used by bootloader
10. SRAM: 2 KB (ATmega328)
11. EEPROM: 1 KB (ATmega328)
12. Clock Speed: 16 MHz

Arduino is an open-source, prototyping platform and its simplicity makes it ideal for hobbyists to use as well as professionals. The Arduino UNO contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. The Arduino UNO differs from all preceding boards in that it does not use the FTDI USB-to-serial driver chip. Instead, it features the Atmega8U2 microcontroller chip programmed as a USB-to-serial converter. “Uno” means one in Italian and is named to mark the upcoming release of Arduino 1.0. The Arduino Uno and version 1.0 will be the reference versions of Arduno, moving forward. The Uno is the latest in a series of USB Arduino boards, and the reference model for the Arduino platform.

You can read more about the Arduino here – www.arduino.cc.