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Topic: 5110 LCD streaks and contrast (Read 4405 times) previous topic - next topic

NickPyner

Dec 12, 2012, 02:39 am Last Edit: Dec 12, 2012, 02:44 am by NickPyner Reason: 1
Further to my struggles with the 5110, has anybody a link that gives the good oil on contrast and streaking?

I have it running nicely with text but the graphics could be better. Perhaps I am expecting too much, or maybe just unlucky, but somebody has a really nice multi-channel voltmeter on youtube.

I have had a couple of goes at the Set LCD Vop setting and am now using 0xB5. This has made one hell of an improvement but it is really just by blunder, and I would rather know a bit more about what I'm doing.

This is all with Pawel's digital timer, I have not tried mixing text and graphics, and I have not tried any other adjustment in LcdInitialise. I guess it is inherently easier to get the text right and all those dark areas makes graphics more demanding on the LCD. I am running it on a 9v supply.

 

MarkT

As I understand it that display is a passive matrix, not TFT, so there is inevitably some level of interference between pixels.

Post a picture of what you see on it - others may then be able to decide if that's normal or erroneous?
[ I won't respond to messages, use the forum please ]

floresta

Nick:

You could really increase your chances of getting help by including more information in your original post.

By not giving any information about the device (5110), the  program (Set LCD Vop), or the mysterious Pawel you are limiting yourself to those who are already familiar with all that stuff.

There's a possibility that others out there have used something similar but don't recognize those particular terms and don't know that their experience could help you.

Of course they could always do a search but on the other hand why bother spending time doing a search when the OP didn't bother to post this basic information?


Don

NickPyner

#3
Dec 12, 2012, 07:00 am Last Edit: Dec 12, 2012, 07:48 am by NickPyner Reason: 1

As I understand it that display is a passive matrix, not TFT, so there is inevitably some level of interference between pixels.

Post a picture of what you see on it - others may then be able to decide if that's normal or erroneous?


Thanks for your comment. I appreciate that the 5110 is pretty old, we have three 5110 phones in service - the best phone ever. I guess you are right, and Nokia may keep the screen clean by careful control and careful choice of what to show.  The streaks appear to vary. There is virtually nothing there right now and it is very hard to photograph.  There may even be some optical illusion in this, the van der Biezold effect perhaps.  The main problem is in the graph bar, about ten pixels in from each end.  Looking through a loupe, I can't see any streaking but I can now see that the pixels in question at the right are actually faulty. They are not so bad individually at the left, but the cumulative effect is worse. You can see, though, that the bad patches in the bar align with the gaps between the characters above, so maybe there is more than one problem in play.

I have three little sketches, clock ( badly streaked), graphics (rather washed out), and text (excellent). I copied the initialisation from the text to the others. The clock was a lot better but it did nothing for the graphics.

void LcdInitialise(void)
{
 pinMode(PIN_SCE,   OUTPUT);
 pinMode(PIN_RESET, OUTPUT);
 pinMode(PIN_DC,    OUTPUT);
 pinMode(PIN_SDIN,  OUTPUT);
 pinMode(PIN_SCLK,  OUTPUT);

 digitalWrite(PIN_RESET, LOW);
 digitalWrite(PIN_RESET, HIGH);

 LcdWrite(LCD_CMD, 0x21);  // LCD Extended Commands.
 LcdWrite(LCD_CMD, 0xBf);  // Set LCD Vop (Contrast). //B1
 LcdWrite(LCD_CMD, 0x04);  // Set Temp coefficent. //0x04
 LcdWrite(LCD_CMD, 0x14);  // LCD bias mode 1:48. //0x13
 LcdWrite(LCD_CMD, 0x0C);  // LCD in normal mode. 0x0d for inverse
 LcdWrite(LCD_C, 0x20);
 LcdWrite(LCD_C, 0x0C);
}

I would like to better understand the contrast, and bias. Perhaps there is not much there to understand. Even Lang's magnum opus has nothing to say.

http://ianlangelectronic.webeden.co.uk/#/lcd-module-0/4569058582

Here is the clock. The text seems fine. I'm pretty pleased with that.


NickPyner

#4
Dec 12, 2012, 07:21 am Last Edit: Dec 12, 2012, 07:25 am by NickPyner Reason: 1


you are limiting yourself to those who are already familiar with all that stuff.



The information I have given is as adequate as you are likely to see. The people I want to hear from are exactly as you describe.  They will know about the contrast control for the 5110, or if they don't, I won't be too surprised. The 5110s are so haphazard and variable, that the best information I can give is that it is on a red circuit board, which is not likely to be relevant.  

floresta

Quote
The information I have given is as adequate as you are likely to see.


I am sorry that you feel offended when someone tries to help you improve.  I never said that your information was inadequate, I just gave you some tips on how you could make it better.

I had no idea that the number 5110 referred to a phone otherwise I never would have even looked at the thread.  I thought it might be an LCD that I hadn't heard of before.  Before you get upset again I mention this because, if you had included the word phone in the thread subject, you might have attracted the attention of people who had similar problems with LCDs obtained from other phones, maybe even other phones with the same type of display.


Don

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