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[on:]

Hi, I have made a prototype using a Nokia 5110 LCD and an ATMEGA328P. The display is powered at 3.3V as well as the ATMEGA328P used on this project, and they are directly connected (no resistences between them, since both use the same power supply). I have used Adafruit library, and also this library: http://code.google.com/p/pcd8544. I had some contrast problems (there was a significant black tint all over, that make it difficult to see the text printed on the LCD), I made some tweaks on the LCD initialization and ended up using the command with the value 0xA8 to configure Vop, instead of the default 0xC2 of the library. This worked ok (for some minutes), then I turned off the unit, when I turned it on again the display was very dim, and after another power down / power up I've never managed to get any image on the display, not even with the original values, and with both libraries, using the included examples, that worked previously (with some blackish tint as I said before). It seems that the display is dead. Is there any possibility of killing the display by setting different parameters for Vop? Any idea of what could be the reason for this?

Thanks in advance

Fernando

[Reply #1 on:]

The best information on the 5110 I know of is here

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

I found the quality of the display depended very much on what was being displayed. There was evidence of this in that I used several programmes that did not use the Philips library. The best of these was an exercise in text by Stuart Lewis. When I used his parameters in the others, it didn't help much. When I got the Philips library, I fiddled with some settings in the cpp file. I can't remember what I did, but I see I have the VoP as 0xC2.

I am really pleased with the 5110. I have had two running for weeks and two more on the way. One thing I have learned is that blue lighting is for nancies. If yours have blue background LEDs, you might be better off without them.

[Reply #2 on:]

What I've found with my 5110 is that if I press the frame of it against the pc board with my fingers, the display has much more contrast. I found this out by accident.  I noticed sometimes it looked very dim, and other times it looked great.  Maybe it's just my display, but it's pretty consistent.  I'm planning to mount it in a case, and screw it in to keep it under (slight) constant pressure.

I've read about lots of different values for VoP (search on sparkfun.com), here's what I'm currently using:

 

Code:

sendCommand( 0xB1, LCD_CMD );  // Set LCD Vop (Contrast) - B1 to Bf

-transfinite

[Reply #3 on:]

Respect the datasheet, add a voltage divider with resistor for 3v logic level