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    16x2 lcd display problem

    my 16x2 lcd is working in a PIC development board with sample program of MikroC.
    but same connection, doesnt work in my circuit. i dont kno whats wrong.

    normally if power is supplied to LCD, dark square boxes will appear on screen. but in my case, i cant get that from my circuit. so, i took it as some kind of power problem. i get the power from a function generator. im using Variable resister for reference voltage pin.

    do you have any idea to solve the problem?

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    Re: 16x2 lcd display problem

    post your circuit and code here...
    " It is so simple to be happy,
    but it is so difficult to be simple"


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    Re: 16x2 lcd display problem

    Hi
    Even I faced the same problem when interfacing LCD with some other microcontroller, Check the applied Vdd voltage to the LCD , check for proper grounding of LCD and have u placed a POT for the backlight adjustment if all these are proper then I think the problem might be with your code ie your code is being struck somewhere.
    AS



    •   Alt30th June 2011, 05:17

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    Re: 16x2 lcd display problem

    firstly only connect
    pin 1-->GND
    pin 2-->VCC
    pin 3-->pot(10k) varying between vcc and gnd
    pin15-->GND
    pin16-->Vcc

    The backlight should glow and after adjusting the pot...you will get black rectangles on one line...lower line



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    Re: 16x2 lcd display problem

    What is your voltage and current rating????/
    " It is so simple to be happy,
    but it is so difficult to be simple"



    •   Alt30th June 2011, 06:19

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    Re: 16x2 lcd display problem

    Yes you should probably tell us what lcd you have...atleast the name on the lcd...so that we can refer to the datasheet



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    Re: 16x2 lcd display problem

    my LCD is LMB162ABC

    i think i have problem with reference voltage supply..
    i set that as 1V-2V by using resistor and variable resistor..
    and need to know the range of the reference voltage...



    •   Alt1st July 2011, 01:20

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    Re: 16x2 lcd display problem

    You mean reference supply voltage at pin 3 of LCD. it i am right then it should be 5V and controlled via a potentiometer......
    " It is so simple to be happy,
    but it is so difficult to be simple"


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    Re: 16x2 lcd display problem

    yes you need to connect a potentiometer(10k would do) at pin 3,
    the input to that pin must vary from 0-Vcc...its the contrast adjustment


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    Re: 16x2 lcd display problem

    what is the max voltage has to be given to pin-3 by potentiometer..?
    one of my mate says, the range for contrast adjustment is 0V - 0.7V... it means- 0V for high contrast, and 0.7V for minimum contrast. from the potentio meter we need to set that voltage to pin-3. is it correct? i ddint check it that.
    Can we Ground the 3rd pin?



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    Re: 16x2 lcd display problem

    Niru just make a small connection...
    do not connect your microcontroller right now.
    just connect the power...
    pin 1-->gnd
    pin 2-->Vcc
    pin 3-->potentiometer(10k) middle pin(potentiometers other pins connected to vcc and gnd)
    pin15(anode)-->330 ohm resistance-->Vcc
    pin16(cathode)-->GND

    turn the potentiometer to see the effect
    Check the datasheet of your device you will find these settings i have given above...



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    Re: 16x2 lcd display problem

    Hi friend

    I have experiance that
    if data line is not connected properly then also this type of problem arise.
    Check your data line connection between micro and LCD

    Shyam,



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    Re: 16x2 lcd display problem

    thanks all for the valuable advice..

    i have solved the problem..

    normally potentiometer is used to supply reference voltage to pin-3... so we can adjust the voltage value of pin-3 by potentiometer. the voltage range of pin-3 has become 0V-5V..
    before i thought we need to give high reference supply for high contrast..(for LMB162ABC). but for the high contrast, low voltage has to be given to pin-3. it should be 0V-0.7V.. ( 0V for max contrast, 0.7V for min Contrast).
    i have grounded the 3rd pin with out using any potentiometer, and got the wright ans..

    thank u all..



    •   Alt2nd July 2011, 02:16

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    Re: 16x2 lcd display problem

    i have the same problem.my code runs smoothly but when i tested it on real lcd, no display is shown. can you help tell me the what's the problem?


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    Re: 16x2 lcd display problem

    16*2 lcd

    pin 1 -->> ground

    pin 2-->> vcc

    pin 3 -->> 1k resistor between ground Click image for larger version. 

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