problem regarding interfacing LCD using ATMEGA16 code by CHINMAY CHINARA

[query]

I am using the JHD162A LCD and based on the tutorial code.The connections are made as per the tutorial circuit diagram. But instead of showing an ‘A’ on the screen what I see is the backlit display is on and the first line of the screen is filled with black squares. Even if I increase or decrease the contrast pot only the black sqares become dark or light and no other output is obtained. Kindly help me out with it.

[dagakshay]

this sounds some loose connection problem…

[Tuhin]

You have made a worng connection. Just see the back sibe of LCD and conform which pin is no1. and so on. Then connect it. I myself suffered from this problem.I’m giving you the pin configration of LCD you connect it as per your requirment.

 

1.GND

2.VDD(5V or 3V)

3.V0(Contrast adjustment)

4.RS

5.R/W

6.EN

7.DB0

8.DB1

   :

   :

   :

14.DB7

15.LED+(~ 4.2V)

16.LED-(GND)

            Just see the backside of lcd and make sure  your connection is right or not.  

[Sagar]

m having same problem with JHD162A ATmega16

heres the code…

 

//#define F_CPU 16000000

#include <avr/io.h>
//#include <util/delay.h>

#define lcd_data PORTB

/*

PD.0=rs
PD.1=rw
PD.2=en

*/

void lcdbusy() //function to monitor d7th bit (busy flag)
{
    DDRB=0x7f;// this will make msb of portb to input

    PORTD=0xfe;// rs=0 rw=1 en=1, rw=1->read from lcd

    while(PINB>>7) //move the msb to lsb
    {

        PORTD |=0x04; //en-> from low to high
        PORTD &=0xfb; //en-> from high to low
    }

    DDRB=0xff;//make PORTB for output

}

void initlcd()
{
    DDRD=0xff; //PORTD as output
    DDRB=0xff; //portb as output
    
    lcd_data=0x38; //8 bit,5×7 dots
    PORTD=0xfc; //rs=0 rw=0 en=1, 0xfc where c=1100
    PORTD=0xf8; //rs=0 rw=0 en=0, 0xf8 where 8=1000, frm en->high to low

    lcdbusy(); // w8 b4 executing next command

    lcd_data=0x0f; //cursor blinking display on
    PORTD=0xfc;
    PORTD=0xf8;

    lcd_data=0x01; // clear lcd
    PORTD=0xfc;
    PORTD=0xf8;

    lcdbusy();

    lcd_data=0x06; //entry mode
    PORTD=0xfc;
    PORTD=0xf8;

    lcdbusy();
}

void lcdcmd(unsigned char ch)
{
    lcd_data=ch;
    PORTD=0xfc;
    PORTD=0xf8;

    lcdbusy();
}

void lcdchar(unsigned char ch)
{
    lcd_data=ch;
    PORTD=0xfd; // 0xfd where d=1101 rs=w rw=0 en=1
    PORTD=0xf9; //9=1001 rs=1 rw=0 en=0, en-> from high to low
    lcdbusy();
}

void lcdstring(char *str)
{
    while(*str)
    {
        lcdchar(*str);
        str++;
    }
}

int main()
{
    initlcd();
    lcdcmd(0x80);// move cursor to 1st line 1st column
    lcdstring(“Welcome ATmega16 !”);

    while(1);

    return 0;

}

 

 

m i missing something ?

[Sagar]

hey guys solved my problem…. !

 

this is wat i did.

 

added little delay betwn two instruction of enable pin.

 

@query :  add _delay_ms(1); after each high to low pulse for enable pin.

surely this will work for you.

[Author]

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