Go Down

Topic: LCD not working with arduino powered (Read 3018 times) previous topic - next topic

floresta

Quote
i tried and backlight lits up but no solid boxes

That's step 1.

What happens when you turn the potentiometer in step 2?

Did you try connecting pin 3 to GND?


Don


Quote
i tried and backlight lits up but no solid boxes

That's step 1.

What happens when you turn the potentiometer in step 2?

Did you try connecting pin 3 to GND?


Don


yes i did, i tried step 2 too but still nothing appeared except that the backlight is on all the time

Paul__B

So just to clarify, you have pins 1 an 2 connected to ground and +5V respectively, (what are you using to source the 5V, by the way?,) you have the backlight power through a resistor on pins 15 and 16.

You have a 10K potentiometer also connected between ground and +5V with the wiper connected to pin 3, and you try varying it from one end to the other.  The boxes should show up at one point or another, generally closer to the ground end.


So just to clarify, you have pins 1 an 2 connected to ground and +5V respectively, (what are you using to source the 5V, by the way?,) you have the backlight power through a resistor on pins 15 and 16.

You have a 10K potentiometer also connected between ground and +5V with the wiper connected to pin 3, and you try varying it from one end to the other.  The boxes should show up at one point or another, generally closer to the ground end.



+5V from the arduino from usb connection

when i placed the potentialmeter and turned 1 whole round, the boxes didn't appear at all only the backlight lits up

Paul__B


when i placed the potentiometer and turned 1 whole round, the boxes didn't appear at all only the backlight ligts up


That sounds bad.

Can you post a close up picture of how you wired the LCD?
All you need right now is GND on pin1 and pin3 and 5V on pin2 on your LCD. Don't connect pins 15, 16.
If you see backlight instead of blocks, it means you're connecting the wires to pins 16, 15, 14 and not 1, 2, 3. Make sure you're connecting the wires to the correct pins.


Can you post a close up picture of how you wired the LCD?
All you need right now is GND on pin1 and pin3 and 5V on pin2 on your LCD. Don't connect pins 15, 16.
If you see backlight instead of blocks, it means you're connecting the wires to pins 16, 15, 14 and not 1, 2, 3. Make sure you're connecting the wires to the correct pins.


tried the bold method, but now nothing appears in the screen not even the backlight from the picture i provided

i can show a picture of the full connection but my wire connection are messy


HazardsMind

Pin1: Ground
Pin2: 5V
Pin3: needs a pot between 5V - 0V
~
~
Pin15: 5V
Pin16: Ground
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

@HazardsMind:
We've been through that. You can connect Pin3 to GND (for testing). You don't need backlight on a transflective LCD to see something, so there is no need for Pin15/16 right now.

@ArchDemise:
To me this looks like a dead LCD.

HazardsMind

#24
Sep 12, 2013, 08:05 pm Last Edit: Sep 12, 2013, 08:07 pm by HazardsMind Reason: 1
I was going by the PDF. I also read all the posts so far and I too believe it's dead.

All in favor that's its a dead LCD?
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

floresta

Quote
All in favor that's its a dead LCD?


It's more likely to be an 'extended temperature' display in which case it needs a negative voltage on pin 3. 

To check this out you will need another power supply, a 9-volt battery will do.  You will need your original power supply connected to pins 1 and 2 of the LCD as before.

Connect the POSITIVE terminal of the battery to GND and the negative terminal to one end of your potentiometer. 

Connect the other end of the potentiometer to GND and connect the wiper to pin 3. 

Now adjust the potentiometer and see if you get a row of boxes.


Don

#26
Sep 13, 2013, 02:52 am Last Edit: Sep 13, 2013, 02:57 am by TheCoolest Reason: 1
Don, just out of interest, shouldn't such an LCD have an extra pin to drive the display itself built into the PCB?

*Edit* LCD Datasheet says LCD drive voltage is -0.3 - 13V.
http://www.pic16.com/wzsl/lma162a.pdf

floresta

Quote
Don, just out of interest, shouldn't such an LCD have an extra pin to drive the display itself built into the PCB?


I haven't come across any character LCDs that have a negative supply although many graphical LCDs do.

Quote
LCD Datasheet says LCD drive voltage is -0.3 - 13V.


So it's quite possible that a negative voltage is required at pin 3.

Notice that it is an 'extended temperature' device, down to -20 rather than 0.


Don


so i have no choice but to get a new LCD display?


Go Up