Interfacing 16X2 LCD With PIC Microcontroller using miKroC ,CSS and proteus

LCD Interfacing with PIC microcontroller

LCD (Liquid Crystal Display):

In recent years the Alphanumeric display(Liquid Crystal Display) has been finding widespread and replacing "Seven segment display".

Why we prefer LCDs over LEDs..............

1. The declining cost of LCDs.

2. The LCD's can display numbers, characters, and graphics. In contrast,
LEDs, which are confined to display numbers and a few characters.

3.Manfacturers provide built in controller with LCD to control refresh rate as a result no need to write code in PIC18 for that task. Conversely, separate routine is required to refresh LEDs to carry displaying the information.

4. Simple programming for characters and graphics.

More importantly, LCD current(mA) requirement in comparison of seven segment displays is considerably low. Furthermore, Latest LCDs modules permit the coder to define custom character and graphics.

Once you find out how to interface it, it'll be the best and extremely reliable output device utilized by you. Moreover, to debug the code LCD can be easily utilized if you don't have debugger.

Pin Configuration table for a 16X2 LCD character display:-

Pin Number	Symbol	Function
1	Vss	Ground Terminal
2	Vcc	Positive Supply
3	Vdd	Contrast adjustment
4	RS	Register Select; 0→Instruction Register, 1→Data Register
5	R/W	Read/write Signal; 1→Read, 0→ Write
6	E	Enable; Falling edge
7	DB0	Bi-directional data bus, data transfer is performed once, thru DB0 to DB7, in the case of interface data length is 8-bits; and twice, through DB4 to DB7 in the case of interface data length is 4-bits. Upper four bits first then lower four bits.
8	DB1
9	DB2
10	DB3
11	DB4
12	DB5
13	DB6
14	DB7
15	LED-(K)	Back light LED cathode terminal
16	LED+(A)	Back Light LED anode terminal

Now that was all regarding the signals and also the hardware .Next, we discuss how one can send signals to LCD to display required information.

The information you want to display on LCD is kind of data signals and RS,E and RW categorized as control signals. To display data on LCD, First we send data then we put logic LOW on RS pin and RW pin and send high to low pulse to enable pin.

LCD needs a time of 39-43µS to display a character or if you want to execute any command like move the cursor on the right or left. In a similar manner, some operations like clearing display requires more time (1.63ms).Programmer must consider required time intervals when sending data, because if the defined time duration is not provided LCD controller may not display or execute commands.

Generally, Manufacturer provides two different kinds of RAMs within the LCD module ,Display data RAM which is responsible to hold the letters and the other one is Character Graphic RAM which permits user to define their custom or non standard characters.

Don't worry the above all operation can be automatically handle by using predefined library in miKroC and CSS.

Commands:

Instruction

Instruction Code

Instruction Code Description

Execution time

R/W

DB7

DB6

DB5

DB4

DB3

DB2

DB1

DB0

Read Data From RAM

Read data from internal RAM

1.53-1.64ms

Write data to RAM

Write data into internal RAM (DDRAM/CGRAM)

1.53-1.64ms

Busy flag & Address

AC6

AC5

AC4

AC3

AC2

AC1

AC0

Busy flag (BF: 1→ LCD Busy) and contents of address counter in bits AC6-AC0.

39 µs

Set DDRAM Address

AC6

AC5

AC4

AC3

AC2

AC1

AC0

Set DDRAM address in address counter.

39 µs

Set CGRAM Address

AC5

AC4

AC3

AC2

AC1

AC0

Set CGRAM Address in address counter.

39 µs

Function Set

Set interface data length (DL: 4bit/8bit), Numbers of display line (N: 1-line/2-line) display font type (F:0→ 5×8 dots, F:1→ 5×11 dots)

39 µs

Cursor or Display Shift

S/C

R/L

Set cursor moving and display shift control bit, and the direction without changing DDRAM data

39 µs

Display & Cursor On/Off

Set Display(D),Cursor(C) and cursor blink(b) on/off control

39 µs

Entry Mode Set

I/D

Assign cursor moving direction and enable shift entire display.

0µs

Return Home

Set DDRAM Address to “00H” from AC and return cursor to its original position if shifted.

43µs

Clear Display

Write “20H” to DDRAM and set DDRAM Address to “00H” from AC -Address
Counter

Proteus Simulation of Interfacing 16X2 LCD With PIC18F4580 Microcontroller

miKroC Code for Interfacing 16X2 LCD With PIC 18F4580 Microcontroller

// LCD module connections

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[] = "Welcome";

char txt2[] = "Lcd Example";

char txt3[] = "PIC18F4580";

char txt4[] = "Hello!";

char i; // Loop variable

void Move_Delay() { // Function used for text moving

Delay_ms(500); // You can change the moving speed here

}

void main(){

ADCON1 = 0xff;

CMCON = 0x7;

Lcd_Init(); // Initialize LCDa

Lcd_Cmd(_LCD_CLEAR); // Clear display

Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off

Lcd_Out(1,6,txt4); // Write text in first row

Lcd_Out(2,6,txt1); // Write text in second row

Delay_ms(2000);

Lcd_Cmd(_LCD_CLEAR); // Clear display

Lcd_Out(1,1,txt3); // Write text in first row

Lcd_Out(2,5,txt2); // Write text in second row

Delay_ms(2000);

//Moving text

for(i=0; i<4; i++) { // Move text to the right 4 times

Lcd_Cmd(_LCD_SHIFT_RIGHT);

Move_Delay();

}

while(1) { // Endless loop

for(i=0; i<8; i++) { // Move text to the left 7 times

Lcd_Cmd(_LCD_SHIFT_LEFT);

Move_Delay();

}

for(i=0; i<8; i++) { // Move text to the right 7 times

Lcd_Cmd(_LCD_SHIFT_RIGHT);

Move_Delay();

}

Proteus Simulation of Interfacing 16X2 LCD With PIC18F4580 using CSS Code

CSS Code for Interfacing 16X2 LCD With PIC 18F4580 Microcontroller

#define LCD_TYPE 2

#include <flex_lcd.c>

void main()

{

setup_adc_ports(NO_ANALOGS|VSS_VDD);

setup_adc(ADC_OFF|ADC_TAD_MUL_0);

setup_psp(PSP_DISABLED);

setup_spi(SPI_SS_DISABLED);

setup_wdt(WDT_OFF);

setup_timer_0(RTCC_INTERNAL);

setup_timer_1(T1_DISABLED);

setup_timer_2(T2_DISABLED,0,1);

setup_comparator(NC_NC_NC_NC);

setup_vref(FALSE);

lcd_init(); // Always call this first.

lcd_putc("\fHello World\n");

lcd_putc("");

while(1){

lcd_putc("\fHello World\n");

lcd_putc("CSS CODE Test");

delay_ms (1);

}

Friends for further learning about PIC18 checkout

https://microcontrollerpicavr.blogspot.com/2017/08/counter-programming-of-pic18f-using.html

PIC18f4580 Timer0 calculation using miKroC , CSS and proteus

PIC18f4580 TIMER PROGRAMMING The PIC18f4580 has four timers. they're named as Timers zero, one, two, and three. they will be used either as timers to come up with a time delay or as counters to count events happening outside the microcontroller. First, we see however Timers zero is employed to come up with time delays. Every timer wants a clock pulse to tick. The clock supply will be internal or external. If we have a tendency to use the inner clock supply, then 1/ fourth of the frequency of the crystal oscillator on the OSC1 and OSC2 pins (Fosc/4) is fed into the timer. Therefore, it's used for time delay generation and for that reason is termed a timer. By selecting the external clock choice, we have a tendency to feed pulses through one among the PIC18's pins: this is often known as a counter. GIF taken from https://exploreembedded.com Basic registers of the timer Majority of t timers in 18F are 16 bits wide. Because the PIC 18 has an 8- bit ...

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