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[SOLVED] 20x4 LCD not working with Pic18..Need Help.....

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Praveen Kumar P S

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Hello Guys.........

I connected my 4x20 lcd to pic18f4550..But it not even displaying a character.....i used a 10k pot for contrast....The Backlight is working fine....i used 4 lcd pin for data (D4-D7) , Remaining data pins (D0-D3) are left alone...I dont know why it is not working ....

Plz Help me Guys.............
 

Hi,

You do not mention the RS E and RW pins which control the data flow ?

If you are building your own circuit double check all the connections; poor wiring / soldering to the lcd is a very common fault.

If thats all ok, as said above post your code and circuit.

Does your lcd display 'black' boxes when powered on and the contrast turned up ?
 

Hey guys....
Here is my code......

Code: 
#include <18f4550.h>
#fuses NOWDT,NOPROTECT,NOLVP,NODEBUG,NOPBADEN,PUT,HS,BROWNOUT
#use delay(clock=48000000)           
#include <flex_lcd416.c>
#define Hs PIN_A1
void main()                                        
{ 
 lcd_init(); 
while(1)
   {                  
    lcd_setcursor_vb(1,1);
    Delay_ms(10);
    lcd_gotoxy(3,1);
    lcd_putc("EMBEDDED LAB!");                          
    delay_ms(10);
    output_bit(Hs,1);
    delay_ms(100);
    output_bit(Hs,0);
    delay_ms(100);
    
   }
    
}


Here my connection...........

7428272900_1410532161.png


When Power on, Black Box Appear for 5 sec then it disappears ............

I m using Flex_lcd.h
B0,B1,B2 connected to D0,D1,D2 of LCD Respectively
B4,B5,B6,B7 connected to D4,D5,D6,D7 of LcD Respectively....
BackLight appears to be fine..........
Plz Help me guys
Thank You....
 
Last edited:

Post the complete CCS C code. Show the LCD defines.
 

Guys i m having a problem .....
i tried to run a code for lcd blinking ....the code is given below....

Code: 
#include <18f4550.h>
#use delay(clock=40000000)
#fuses NOWDT, PUT, NOPROTECT, BROWNOUT, NOMCLR, NOLVP, NOCPD, INTRC
void main(void)
{
 
 for(;;)
 {
  output_low(PIN_A0);
  delay_ms(30);
  output_high(PIN_A0);
  delay_ms(30);
 }
}

But its not working....PIN_A0 is giving voltage of 0.65 V....I think my Pic is damaged....8-O

i think i have given a 5V supplay to PIN_A0 ,carelessly ..which ruined my pic....

also i doubt the fuse i have used....

Plz help me guys.....

Thank YOU
 
Last edited:

Your fuse settings is correct. Try another pin instead of A0. 30 ms delay is too small. Increase it to 500 ms.
 

milan.rajik said:
Your fuse settings is correct. Try another pin instead of A0. 30 ms delay is too small. Increase it to 500 ms.
Click to expand...

I did that milan....
But no pins in ANY PORT is giving me voltage above 1V..Execpt pin B7....
I think i have to buy new pic................
 

You haven't used HS PLL but you are using 40 MHz Clock. I don't know whether it works or not. Please zip and post your CCS C project files. I will test it here.
 

milan.rajik said:
You haven't used HS PLL but you are using 40 MHz Clock. I don't know whether it works or not. Please zip and post your CCS C project files. I will test it here.
Click to expand...

Here is the project which i was using for led blink.......

Thank You...........
 

Attachments

  • Short code lcd.rar
    38.9 KB · Views: 88

Mr praveen

Even though your are are using flel


Code: 
#include <18f4550.h>
#fuses NOWDT,NOPROTECT,NOLVP,NODEBUG,NOPBADEN,PUT,HS,BROWNOUT
#use delay(clock=48000000)           
#include <flex_lcd416.c>////////////////[COLOR="#FF0000"]this is the problem eventough are using flex lcd driver it is only for 16x4 [/COLOR] [COLOR="#00FF00"]there is a driver  named lcd420.c in ccs compiler by default it will not enable change it to #include<lcd420>  [/COLOR]
#define Hs PIN_A1
void main()                                        
{ 
 lcd_init(); 
while(1)
   {                  
    lcd_setcursor_vb(1,1);
    Delay_ms(10);
    lcd_gotoxy(3,1);
    lcd_putc("EMBEDDED LAB!");                          
    delay_ms(10);
    output_bit(Hs,1);
    delay_ms(100);
    output_bit(Hs,0);
    delay_ms(100);
    
   }
    
}
 
Last edited by a moderator:

Code: 
#use delay(clock=40000000)
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP

you need to add fuse for high speed crystal.
for(;;)
{
output_bit(PK,1);
Output_high_A(0Xff);
Output_high_B(0Xff);
Output_high_C(0Xff);
Output_high_D(0Xff);
}
Click to expand...

set port A,B,C,D as output before you use "Output_high_x()".
 

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