[SOLVED] 16x2 lcd display problem

[niru005]

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?

 

[ckshivaram]

post your circuit and code here...

 

[Seetha09]

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.

 

[blunderboy]

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

 

[ckshivaram]

What is your voltage and current rating????/

 

[blunderboy]

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

 

[niru005]

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...

 

[ckshivaram]

You mean reference supply voltage at pin 3 of LCD. it i am right then it should be 5V and controlled via a potentiometer......

 

[blunderboy]

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

 

[niru005]

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?

 

[blunderboy]

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...

 

[g_shyam1682]

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,

 

[niru005]

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..

 

[electronics rock]

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?

 

[bmn.ever]

16*2 lcd

pin 1 -->> ground

pin 2-->> vcc

pin 3 -->> 1k resistor between ground