Arduino/C3/Interfacing-LCD-through-AVR-GCC-programming/English
| Visual Cue | Narration |
| Slide 1: | Welcome to the Spoken Tutorial on Interfacing LCD through AVR-GCC programming. |
| Slide 2:
Learning objectives |
In this tutorial, we will learn to:
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| Slide 3:
Pre-requisites |
To follow this tutorial, you should have basic knowledge of :
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| Slide 4:
System Requirement |
To record this tutorial, I am using:
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| Slide 5:
External Devices |
We also require some external devices such as:
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| Show the image: | In this experiment, we will be using a 16 by 2 LCD.
Please refer to the basic level tutorial of this series to know more about LCD. |
| Show the image: | Make use of the given table to connect the Arduino pins to the LCD.
This table is available in the Additional reading material link of this tutorial. |
| Show the circuit connection(LCD_circuit.jpg) | This is the circuit connection. |
| Point to the pins in the image | Connect one extreme lead of the potentiometer to pin 1 of the LCD.
The other extreme end is connected to pin 2 of the LCD. The middle pin is connected to pin 3 of the LCD. |
| Live setup:
LCD-Setup.JPEG |
This is the live setup of the connection. |
| Now we will write an AVR-GCC program to display the digit 5 on the LCD. | |
| Open text editor | Open any text editor and type the following. |
| Highlight according to narration:
#include <util/delay.h> #include <stdlib.h> |
avr/io.h contains all the basic libraries required to perform the input and output operations.
Util slash delay.h contains the libraries for the delay function. stdlib.h contains the libraries for defining variable types and other commonly used functions. |
| typedef uint8_t byte;
#define ClearBit(x,y) x &= ~_BV(y) #define SetBit(x,y) x |= _BV(y) |
ClearBit(x comma y) is equivalent to cbi(x comma y). It used to clear the yth bit of PORTx.
SetBit(x comma y) is equivalent to sbi(x comma y). It used to set the yth bit of PORTx. |
| #define LCD_RS 0
#define LCD_E 1 #define DAT4 2 #define DAT5 3 #define DAT6 4 #define DAT7 5 #define CLEARDISPLAY 0x01 |
All the numerical pins of the LCD are replaced with the names using hash define.
This is done to make the program easier to understand. |
| void PulseEnableLine()
{ SetBit (PORTB, LCD_E); _delay_us(40); ClearBit(PORTB, LCD_E); } |
The PulseEnableLine function is used to toggle the enable pin of the LCD.
SetBit will set to high and Clearbit will set to low, with a delay in between. |
| void SendNibble(byte data)
{ PORTB &= 0xC3; if (data & _BV(4)) SetBit(PORTB,DAT4); if (data & _BV(5)) SetBit(PORTB,DAT5); if (data & _BV(6)) SetBit(PORTB,DAT6); if (data & _BV(7)) SetBit(PORTB,DAT7); PulseEnableLine(); } |
The SendNibble function is used to send data of one nibble to the PORTB. |
| void SendByte(byte data)
{ SendNibble(data); SendNibble(data<<4); ClearBit(PORTB, 5); } |
The SendByte function is used to send data of one byte to the PORTB. |
| void LCD_Cmd (byte cmd)
{ ClearBit(PORTB, LCD_RS); SendByte(cmd); } |
The LCD underscore Cmd function is used to send a command to the LCD. |
| void LCD_Char (byte ch)
{ SetBit(PORTB, LCD_RS); SendByte(ch); } |
The LCD underscore Char function is used to send a character data to the LCD. |
| void LCD_Init()
{ LCD_Cmd(0x33); LCD_Cmd(0x32); LCD_Cmd(0x28); LCD_Cmd(0x0C); LCD_Cmd(0x06); LCD_Cmd(0x01); _delay_ms(3); } |
The LCD underscore Init function is used to initialise the LCD. |
| void LCD_Clear()
{ LCD_Cmd(CLEARDISPLAY); _delay_ms(3); } |
The LCD underscore Clear function is used to clear the display. |
| void LCD_Message(const char *text)
{ LCD_Char(*text++); } |
The LCD underscore Message function is used to send a string of data to be displayed on the LCD. |
| void LCD_Integer(int data)
{ char st[8] = ""; itoa(data, st, 10); LCD_Message(st); } |
The LCD underscore Integer function is used to send an integer data to the LCD. |
| int main(void)
{ DDRB = 0xFF; LCD_Init(); while(1) { LCD_Clear(); LCD_Integer(5); _delay_ms(600); } } |
This is the main function where we pass the value 5 to the display. |
| Text box to display the message. | This code is available in the Code files link of this tutorial. You can download and use it. |
| Save the file. | I’ll save the code as lcd.c file in the Downloads folder.
Ensure that the Makefile is also present in the same folder. |
| Switch to the terminal. | |
| Type,
> cd /home/spoken/Downloads > make FNAME = lcd |
Go to the folder where lcd.c file is saved.
Type, make space FNAME in capital = lcd and press Enter. |
| Highlight the command | This command creates a .hex file and uploads it to Arduino. |
| Point to the output
LCD-Output.jpeg |
Now you can see that the digit 5 is displayed on the LCD. |
| Slide 6:
Assignment |
Pause the tutorial and do the below assignment.
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| This brings us to the end of this tutorial. Let us summarize. | |
| Slide 7:
Summary |
In this tutorial, we learnt to:
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| Slide 8:
About Spoken Tutorial project |
The video at the following link summarizes the Spoken Tutorial project.
Please download and watch it. |
| Slide 9:
Spoken Tutorial workshops |
The Spoken Tutorial Project Team:
For more details, please write to us. |
| Slide 10:
Forum for specific questions |
Please post your timed queries in this forum. |
| Slide 11:
Acknowledgement |
Spoken Tutorial project is funded by NMEICT, MHRD, Government of India.
More information on this mission is available at this link. |
| This tutorial has been contributed by FOSSEE and Spoken Tutorial Project, IIT Bombay.
This is Priya from IIT Bombay signing off. Thanks for watching. |
