black boxes on 16×2 LCD

[sachin]

i am begineer in microcontroler and making project at89c51 based “A” character display. i make it and after on supply lcd shows black boxes on first row.i am not able to rectify it.what is generally cause of this ? how to solve it? plz tell me step by step…………………………..

[Qaisar]

black boxes means data is not transfering to lcd ..

visit post ”lcd interfacing to 8051 by qurat ain” i put code and diagram there. 

first try that code and diagram . if still u r unable to interface lcd then check ur haedware and lcd connection.

[Qaisar]

black boxes means data is not transfering to lcd ..

visit post ”lcd interfacing to 8051 by qurat ain” i put code and diagram there. 

first try that code and diagram . if still u r unable to interface lcd then check ur haedware and lcd connection.

[Sajjad]

i have the same problem….. i get the results on simulations but i get black boxes on harware…. kindly help me out… i am using thi engineers garage code…..

 

 

 

 

[AJISH ALFRED]

Black boxes on the first row means “LCD not initialized”. Only after proper initialization an LCD can display characters.

Problem could be either hardware or software. First check your circuit connections and then your code.

If possible post your connection diagram here.

[Sajjad]

wysiwyg_imageupload:6726:THIS IS THE CUIRCUIT DAIGRAM I AM USING. i get black boxes in ist row. kindly tell me if there is any flaw? 

[Sajjad]

 

//Program to Display string on LCD using AVR Microcontroller (ATmega16)

/*

LCD DATA port—-PORT B

signal port

---

PORT D

rs

---

PD0

rw

---

PD1

en

---

PD2

*/

 

#include<avr/io.h>

#include<util/delay.h>

 

#define LCD_DATA PORTB //LCD data port

 

#define ctrl PORTD

#define en PD2 // enable signal

#define rw PD1 // read/write signal

#define rs PD0 // register select signal

 

void LCD_cmd(unsigned char cmd);

void init_LCD(void);

void LCD_write(unsigned char data);

 

int main()

{

DDRB=0xff;

DDRD=0x07;

init_LCD(); // initialization of LCD

_delay_ms(50); // delay of 50 mili seconds

LCD_write_string(“EngineersGarage”); // function to print string on LCD

return 0;

}

 

void init_LCD(void)

{

LCD_cmd(0x38); // initialization of 16X2 LCD in 8bit mode

_delay_ms(1);

 

LCD_cmd(0x01); // clear LCD

_delay_ms(1);

 

LCD_cmd(0x0E); // cursor ON

_delay_ms(1);

 

LCD_cmd(0x80); // —8 go to first line and –0 is for 0th position

_delay_ms(1);

return;

}

 

void LCD_cmd(unsigned char cmd)

{

LCD_DATA=cmd;

ctrl =(0<<rs)|(0<<rw)|(1<<en);

_delay_ms(1);

ctrl =(0<<rs)|(0<<rw)|(0<<en);

_delay_ms(50);

return;

}

 

void LCD_write(unsigned char data)

{

LCD_DATA= data;

ctrl = (1<<rs)|(0<<rw)|(1<<en);

_delay_ms(1);

ctrl = (1<<rs)|(0<<rw)|(0<<en);

_delay_ms(50);

return ;

}

 

void LCD_write_string(unsigned char *str) //store address value of the string in pointer *str

{

int i=0;

while(str!=’’) // loop will go on till the NULL character in the string 

{

LCD_write(str); // sending data on LCD byte by byte

i++;

  }

return;

}

THIS IS THE CODE i am using. 
i have used the control pins and data pins according to code…

[anand]

Did you try adjusting the contrast of LCD with potentiometer connected. These boxes also would be seen if you set the contrast to dark…

[Sajjad]

yes i did.. but nothing changes. i only get these boxes nothing else

[AJISH ALFRED]

Hi Sajjad,

In your code, you are writing into ctrl which is defined as portD (#define ctrl PORTD) at somany lines, but you haven’t connected the portD of your controller to anywhere !

[Bala murugan]

I have same problem ….i was using engineersgarage circuit and code but not working .plz help me

wysiwyg_imageupload:11996:

[Ashutosh Bhatt]

try to do one thing. connect RW pin of LCD to ground. and read LCD datasheet for proper operation initialization.

[SHAH DISHANT H.]

The issue seems with Initilisation process. Send following commands.

0x38

0x0E

0x01

0x06

0x80

 

Provide enough delay inbetween. What is the frequency of crystal you have connected?

[Ganesh Selvaraj]

And also check if you connected everything properly… one loose contact and the LCD won’t work like we expect it to… #personal_experience

[Author]

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