CHAPTER 3
I/OS
Eng. Hazem W. Marar
LCDS
Simply, the LCD consists of 6 panels. The most
important part is a set of two transparent panels with a
liquid crystal solution between them. Light is shined
from behind the panels. Each crystal either allows light
to pass through or blocks the light. The configuration of
the crystals forms the image.
LCD PINOUT
HOW TO INTERFACE
THE LCD?
CODE
sbit LCD_RS at RB4_bit;
sbit LCD_EN at RB5_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB1_bit;
sbit LCD_D6 at RB2_bit;
sbit LCD_D7 at RB3_bit;
sbit LCD_RS_Direction at TRISB4_bit;
sbit LCD_EN_Direction at TRISB5_bit;
sbit LCD_D4_Direction at TRISB0_bit;
sbit LCD_D5_Direction at TRISB1_bit;
sbit LCD_D6_Direction at TRISB2_bit;
sbit LCD_D7_Direction at TRISB3_bit;
// End LCD module connections
char txt1[ ] = "LCD Example";
char i;
// Loop variable
void main(){
ANSEL = 0;
// Configure AN
pins as digital I/O
ANSELH = 0;
C1ON_bit = 0;
// Disable
comparators
C2ON_bit = 0;
Lcd_Init();
// Initialize LCD
Lcd_Cmd(_LCD_CLEAR);
// Clear
display
Lcd_Cmd(_LCD_CURSOR_OFF);
//
Cursor off
Lcd_Out(1,6,txt1);
// Write text in
first row
// Moving text
for(i=0; i<4; i++) {
// Move text to the
right 4 times
Lcd_Cmd(_LCD_SHIFT_RIGHT);
Delay_ms(1000);
}}
WRITE A CODE TO CHECK WHICH
PIN IS CLICKED IN PORT D
KEYPAD INTERFACING
KEYPAD CODE
unsigned short kp = 0;
char txt[6];
// Keypad module connections
char keypadPort at PORTD;
// End Keypad module connections
void main() {
Keypad_Init();
Keypad
ANSEL = 0;
ANSELH = 0;
// Initialize
while(1) {
kp = 0;
// Wait for key to be pressed and
released
while (!kp);
{ kp = Keypad_Key_Click();}
// Store key code in kp variable
switch (kp) {
case 1: kp = 49; break; // 1
case 2: kp = 50; break; // 2
case 3: kp = 51; break; // 3
case 4: kp = 52; break; // 4
case 5: kp = 53; break; // 5
case 6: kp = 54; break; // 6
case 7: kp = 55; break; // 7
case 8: kp = 56; break; // 8
case 9: kp = 57; break; // 9
case 10: kp = 42; break; // '*'
case 11: kp = 48; break; // '0'
case 12: kp = 35; break; // '#'
default: kp += 48; } }}
SAMPLE CODE
do {
case 9: kp = 55; break; // 7
kp = 0;
case 10: kp = 56; break; // 8
do
case 11: kp = 57; break; // 9
kp = Keypad_Key_Click();
case 13: kp = 42; break; // *
while (!kp);
case 14: kp = 48; break; // 0
switch (kp) {
case 1: kp = 49; break; // 1
case 2: kp = 50; break; // 2
case 3: kp = 51; break; // 3
case 5: kp = 52; break; // 4
case 6: kp = 53; break; // 5
case 7: kp = 54; break; // 6
case 15: kp = 35; break; // #
}
Lcd_Chr(1, 10, kp);
// Print key ASCII value on
LCD
} while (1);
MAKE A SIMPLE CALCULATOR
HINT: YOU MAY NEED WordToStr(unsigned short, txt);
OR
IntToStr(int, txt);
RELAYS
HOW TO INTERFACE RELAYS WITH PIC ?

Remember transistor ?
MAKE A LOCK/UNLOCK SYSTEM
USE RELAYS TO CONTROL THE OUTPUT SIGNAL
LAB EXERCISE
Chapter 4