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Topic: Nokia 5110 Odd behaviour (Read 368 times) previous topic - next topic

Alzibiff

I am using a UNO board to control a stepper motor and have a NOKIA 5110 LCD display to show various pieces of information.

When powered by a 12V mains adapter, the NOKIA display takes two power cycles before it displays anything although the backlight comes on from the very start. That is: power on (display blank, backlight on), power off, power on (display comes on as does the backlight). Now that is odd and I am stuggling to find a way of getting it to come on at the first attempt.

Switching to a 12V battery supply, the display simply never comes on. At first I thought it was a limited  current issue from the battery but I can drive the stepper motor with both the mains adapter and the battery and I can't see a lot of demand for current from the LCD anyway.

I am resetting the LCD via an R-C pair rather than by software: 47K from RST on the display to Vcc and a 0.1uF capacitor from the RST to GND. I have tried various values to lengthen and shorten the reset pulse but no difference.

I am using the PCD8544 files to drive the LCD.

I guess I could put up with the "second time around and it works" situation when using the mains adapter but this issue stops me using the battery.

I have read something about "bias values" but not a clue how to amend these in the PCD8544 code which is set at its default. (Before anybody asks, I am powering the LCD from 3.3V and using 10K resistors to limit current to the LCD control pins connected to the Arduino).

Alan

MK1888

You're powering the display with 12V?  Isn't that way above its spec?

Alzibiff

You're powering the display with 12V?  Isn't that way above its spec?
Definitely not - that would be silly. I am powering the Arduino with a 12V supply and connecting my NOKIA 5110 display to the Arduino.
The display takes its supply from the 3.3V Arduino pin and is controlled by Arduino I/O pins which, as they bounce between 0V and 5V connect to the NOKIA LCD via 10K resistors.

Thank you for your reply. Hope this makes things clearer and you can offer me some help  - let me know if you need any clarification.

Alan

Nick_Pyner

#3
May 24, 2020, 05:02 am Last Edit: May 24, 2020, 05:05 am by Nick_Pyner
When powered by a 12V mains adapter, the NOKIA display takes two power cycles before it displays anything although the backlight comes on from the very start. That is: power on (display blank, backlight on), power off, power on (display comes on as does the backlight). Now that is odd and I am stuggling to find a way of getting it to come on at the first attempt.
That would suggest mechanical, although no explanation if it really is a strict one-two-one-two sequence. Try power on once. If no display, gently press on it.
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Switching to a 12V battery supply, the display simply never comes on.
That sounds like slack-arsed wiring. You are right in that 5110 runs on practically nothing.
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I am resetting the LCD via an R-C pair rather than by software
I can't imagine why you would want to do that. Just to prove the point, desisting might be a good idea.
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I have read something about "bias values" but not a clue how to amend these in the PCD8544 code which is set at its default.
In my experience, the best thing about the PCD8544 library is that you don't have to amend them. Since you have not complained about the quality of the display, only about your ability to see it, this applies double for you.

Alzibiff

#4
May 24, 2020, 09:01 am Last Edit: May 24, 2020, 09:05 am by Alzibiff
Thank you Nick.
I guess that you are absolutely right about not needing to tinker with any of the library settings given that the display actually IS displaying albeit not every time - and yes, it ALWAYS comes on at the second switch on when on 12V mains adapter power.

I have done some wire wobbling but to no effect. I am going to replace the LCD with another one - I have read elsewhere that some of these displays are very old, that they may still be selling surplus from 90s and that they use conductive grease for wiring inside, which tends to dry up with time and cause issues. (Although what I am experiencing isn't really answered by that idea!).

Many thanks,
Alan

Paul__B

I have read elsewhere that some of these displays are very old
Some of them?  :smiley-roll:

Nick_Pyner

I am going to replace the LCD with another one - I have read elsewhere that some of these displays are very old, that they may still be selling surplus from 90s and that they use conductive grease for wiring inside, which tends to dry up with time and cause issues. (Although what I am experiencing isn't really answered by that idea!).
Yes, they are surplus and/or seconds from the greatest phone ever made, the Nokia 5110. I only have one bad one, and it is OK most of the time. I don't know about the conductive grease. I'm not sure I would rush out and get a replacement these days. You might have a look at the SSD1306. it is similar in size and price, probably more versatile, and may be fine for your purpose. It is also new....

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