PCD8544 - Nokia 5110 Display Blank Screen

[davegior]

I buy from Adafruit because of the great support and tutorials on getting things working easily. However I've bee racking my brains trying to get this PCD8544 display (Nokia 5110) working. All I see is a bank screen and the 4 LED lights.
I tried the suggestions on changing the Contrast code setting but it didn't help.

I used the tutorial from: http://ladyada.net/products/nokia5110/ the library from github: https://github.com/adafruit/Adafruit-PCD8544-Nokia-5110-LCD-library and GFX library: https://github.com/adafruit/Adafruit-GFX-Library and the example pcdtest.

I am using the level shifter chip that came from Adafruit with the display and powering it and the Display with 3.3v power supply.
The level shifter is connected to a ATMega328P (5v).

Can I possible have a bad PCD8544 display? I tried values of 30 to 90 for the contrast in both the Adafruit_PCD8544.h - void begin(uint8_t contrast = 60); and the pcdtest code - display.setContrast(60);
By turning up the contrast I should have seen a black screen but I don't. I see a blank screen.

[adafruit]

strange, can you post up a photo of your wiring? thats the only thing we can think of other than a busted display - and that would be faster to fix!

[davegior]

I have used the ATMega328p and breadboard successfully with the your Monochrome 128x32 OLED graphic display SSD1306.
I have compared the wiring with the tutorial several times originally using pins 3,4,5,6,7 and now using 9,10,11,12,13 of the ATMega328p.

[davegior]

This might show the wiring better:

[davegior]

I also tried using the Arduino Library and Sketches for the Philips PCD8544, the Steward Lewis modified version of the Arduino Sketch and Sparkfun's. All have the same result.
I would like to point out that even with the LED pin removed from the Display, the 4 LED's still illuminate.

[adafruit]

the LED isnt a big deal - its a fet and will stay on for a bit even when the pin is removed

since we think the display may be kaput, there's no risk in connecting the datalines directly and skipping the 4050 - care to try that?

[davegior]

I'll give it a shot sometime tomorrow and let you know.
Thank you for your support

[davegior]

It works without the 4050 and connecting directly to the ATMega328p. I had to lower the contrast to "10" also.
I didn't want to run 5v on the LCD without your consent. Didn't want to damage or shorten the life span of the display.

The 4 LED's stay lit without the LED connection even on startup and reset. They are extremely BRIGHT w/ 5v.
Can I cut a trace on the board to eliminate the LED's and will the life span of the display be shortened w/ 5v as I read in a post?

Thank you for your help.

[adafruit]

it sounds like something was wrong with the 4050 or the wiring. if you tie the LED pin to ground that will turn off the LEDs - just dont leave the pin floating

[davegior]

it sounds like something was wrong with the 4050 or the wiring. if you tie the LED pin to ground that will turn off the LEDs - just dont leave the pin floating

Thanks, will gnd LED pin. I went over the wiring many times for the 4050 and it's wired as per tutorial.

Code: Select all

    Connect pin 1 of the 4050, the LCD VCC pin and the LCD backlight pin to 3.3V.
    Connect pin 8 of the 4050 and the GND pin of the LCD to ground.
    Connect the RST (reset) pin of the LCD (orange wire) to pin 2 of the 4050
    Connect the CS (chip select) pin (yellow wire) to pin 4 of the 4050.
    Connect the D/C (data/command) pin (green wire) to pin 6 of the 4050
    DIN (data in) pin (blue wire) to pin 15 of the 4050
    CLK(clock) pin (purple wire) to pin 12 of the 4050
    Arduino pin 3 (orange) goes to pin 3 of the 4050.
    Arduino pin 4 (yellow) goes to pin 5 of the 4050.
    Arduino pin 5 (green) goes to pin 7 of the 4050.
    Arduino pin 6 (blue) goes to pin 14 of the 4050.
    Arduino pin 7 (violet) goes to pin 11 of the 4050

[adafruit]

without an oscilloscope you'll have difficulty debugging - you can try wiring one pin at a time thru the 4050

[Stu.C]

I had similar problems with a bad 4050 with a different display.

To confirm it's duff, move the 4050 to some free space on the breadboard, connect 3.3V to pin 1 and GND to pin 8. Then connect 5V to pin 3 and check with your multimeter that pin 2 is giving 3.3V. If that one's fine, work your way round each of the in/out pairs and repeat the test for each. Anything other than 3.3V from the outputs and you should put the 4050 in the bin.



Cheers, Stu

[davegior]

Thanks Stu I'll check it out

[RLeyland]

I had similar problems with a bad 4050 with a different display.

To confirm it's duff, move the 4050 to some free space on the breadboard, connect 3.3V to pin 1 and GND to pin 8. Then connect 5V to pin 3 and check with your multimeter that pin 2 is giving 3.3V. If that one's fine, work your way round each of the in/out pairs and repeat the test for each. Anything other than 3.3V from the outputs and you should put the 4050 in the bin.



Cheers, Stu

I've been having the same problem. I've wired up two separate displays, with two different 4050s. One on a breadboard, and one mounted on an adafruit protoboard.. I can switch between displays, because I used a header on the protoboard. One LCD illuminates with very poor contrast, and the other won't show an image at all.

The failing LCD was showing an image, but it gradually faded.

Using an oscilloscope I could see that the output from the 4050s is correct (at 3.3v). On the clock and data lines I can see the signal when the LCD updates.


I am concerned that there is a poor component in the LCD but unsure how to verify this.

An ohm-meter across each resistor shows correct values. 1k, 200 x4 and 0.
What are the capacitor values?

Is there anything I can do to fix the displays?

thanks,
Robert.

PS. I was concerned initially that the 4050 is not rated for 3.3V (the spec sheet show 5, 10 and 15V), but the output on the 'scope was fine.

[adafruit_support_bill]

@Rleyland - the probability of getting two bad displays is very small. Post photos showing your wiring and connections.