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PIC LCD Interface Problem (Hitachi HD44780)

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Tiwana6330

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I hooked up a Hitachi HD44780 based 2x16 LCD with PIC18F2420. Now on the bootup, I should see boxes in the top row (Typical for a HD44780 based LCD). But what I see is 8 boxes in top row and 8 boxes in Bottom row.

Is the LCD Blown or something else is wrong? I have attached a snapshot of LCD display


photo (1).jpg

thanks for your time and help
 

Tiwana6330 said:
I hooked up a Hitachi HD44780 based 2x16 LCD with PIC18F2420. Now on the bootup, I should see boxes in the top row (Typical for a HD44780 based LCD). But what I see is 8 boxes in top row and 8 boxes in Bottom row.

Is the LCD Blown or something else is wrong? I have attached a snapshot of LCD display


View attachment 53699

thanks for your time and help
Click to expand...

sometimes it happens like this...but dnt be worried...you can use the Mikro c Sample programm of lcd...i hope it will work with you...
 

I have my doubt that LCD has gone bad.
Apparently this is the type of LCD where you need to make Vo (contrast pin) as N.C (not connected)
Then try with a working code, if you still have problems post the schematics and code and we'll look into it.
 

ok..Now I have connected the LCD to a working code but somehow, as soon as the controller sends signals to initialize the LCD (I have a LED which Blinks Before going into Initialization), the PIC controller burns out......PIC starts taking over 1 Amp. I took the PIC out of the board and on Digital Multimeter (DMM) the VCC and VDD pins are short (Beep short). I thought that there is some problem in the circuit board so I replaced the controller and ran another blinking LED code and no problems (even though that the LCD was still connected but I was not sending any commands). Later I burned the LCD code on the PIC and as soon as it started sending initialization signals, it burned....

Any clues? Thanks for help
 

the internal CG and DD Ram has gone bad ... i prefer not to use LCD as it in internally getting short when the data is received by registers.
 

Hi Friend

I think your LCD is burn out or bad .
because i have experience that if LCD is OK and code is wrong.
then only upper line of LCD has boxes and lower line is clean.

But if both line has boxes then it is burn out or bad.

change it with new one.

Good Luck
 

abidr said:
I have my doubt that LCD has gone bad.
Click to expand...

I take my words back.....
LCDs and VFDs are nasty things, I have seen many different behavior. The kind you mentioned above I saw this behavior in one of the 16x2 LCD that I used and I solved it the same way I mentioned above and that was to to N.C Vo pin.
Only one reason for this behavior you might have connected the LCD supply in reverse.
 
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check your installation part of LCD, post your installation code, check the contrast control at pin 3 ( here not the issue for 8 digit)
 

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