PCD8544 - Nokia 5110 Display Blank Screen

[RLeyland]

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

One display works but is very faint. I read more here, and increased the contrast to 70% - that display is now fine.

The other display worked (faintly) initially, got more and more faint, and now now longer works at all. (White LEDs ok, picture is blank.)


I'll post pics tomorrow - I left my handy picture taking device at home.

[RLeyland]

Here's the wiring for the displays.

I think it is correct becasue one display works fine, I substitute the other display and it fails.

I've seen images on the bad display, but briefly, and then it fades out.

Weird.

LCD-good.jpg (278.32 KiB) Viewed 1231 times

The Good

LCD-Bad.jpg (206.72 KiB) Viewed 1231 times

The Bad

LCD_board_top.jpg (144.86 KiB) Viewed 1231 times

This the top of the board. The underside has the power connections only.

[adafruit_support_bill]

OK. Contact support@adafruit.com with a link to this thread & ask for a replacement.

[WMdopple]

I'm not sure if it'd be best to open a separate thread for this, but I'm having a blank screen issue similar to the first poster on one of these displays that I recently picked up - the LEDs light up fine but I don't get as much as a flicker from the screen when I try to display. I've verified continuity between my soldered pins on the lower header and the pins on the upper header, and I've played with contrast levels in the sketch as well. I haven't tried it without the level shifter with the Arduino, but I've tested it with a Raspberry Pi so the level shifter doesn't seem to be the issue.

Any other ideas? Unfortunately I don't have an oscilloscope to check it with. I'm attaching a pic of my wiring - I apologize for the tangle but my selection of wire isn't big and I was trying to make it easier to trace. I've rebuilt the circuit several times on two different breadboards, so I'll really feel sheepish if there's a mistake in there.

232.jpg (200.68 KiB) Viewed 1144 times

[adafruit]

can you try removing the level shifter and seeing if that helps? just because that could be the problem. just power the display with 3.3V but use 5V logic. its OK for testing it once.

[WMdopple]

Ok, now I'm getting some odd results.

Connecting it to the Arduino without the level shifter worked, at least to start with. Then the screen became garbled and stopped updating right after the logo display.

The kicker is... now it has suddenly decided to start working when connected to the Raspberry Pi, but it shows the same garbling, seemingly at completely random times. Obviously that's harder to support since it's not Adafruit code driving it, but since those are 3.3v pins I felt safer running more tests that way.

I'd love to hear if there's anything else I can try... since it's being so inconsistent, I think I'm going to try finding one of my larger breadboards and re-do the wiring (*sigh*, yet again) to make a better test-bed in order to verify whether the level shifter definitely isn't working with it. Thanks.

[adafruit]

sounds like the display is fine - we dont know anything about the Pi code - we can only offer suggestions for using it with an Arduino following our tutorial

[WMdopple]

Yes, I understand this. If I were only seeing the display corruption with the Pi, I would not have mentioned...

This evening I wired it back up with the level shifter, on a third breadboard, with new connections for everything. I gave it plenty of time but didn't get any display... but then I unplugged and replugged power on the Arduino, and suddenly the test sketch displayed. I re-checked all connections and tested it a bunch of times now while making certain nothing in the setup was disturbed, to rule out anything like a loose connection flexing. Sometimes it runs through the sketch properly, sometimes nothing displays, and sometimes various patterns are corrupted or only partially draw. I've had a string of blank screens while testing, so it's possible I was just seeing a similar run when I originally posted.

Now I'm not sure how to rule out the level shifter without repeatedly running it directly connected to the arduino. Grasping at straws, but... I could see the possibility of a timing issue with the Pi code, would that be a possibility with the example arduino setup?

[edit]I should probably also note that even when I get a blank screen I'm still getting serial output from the arduino when it initializes testdrawbitmap()

[Stu.C]

Now I'm not sure how to rule out the level shifter without repeatedly running it directly connected to the arduino.

Go back to page 1 of this thread, scroll down, grab your multimeter, do a quick test of the 4050. Or just click here...

[WMdopple]

Now I'm not sure how to rule out the level shifter without repeatedly running it directly connected to the arduino.

Go back to page 1 of this thread, scroll down, grab your multimeter, do a quick test of the 4050. Or just click here...

I get a steady 3.36v on all pairs testing that way. Given the randomness of the issue, though, I'm not sure if that completely rules out a problem there?

[adafruit]

lets try replacing it - email support@adafruit with a link to this thread
let us know if that fixes it, this is a strange problem!

[WMdopple]

Thank you, I will definitely let you know once I'm able to try it out!

[WMdopple]

The replacement appears to be working properly for me when connected to an arduino.

I've also ported the adafruit arduino code over to my Raspberry Pi as a learning project, and it's been working as well. I've seen one or two other projects that have done the same, but it's a great learning project - not a lot of code to change, but a lot of little differences that take a bit of research to resolve. Using the WiringPi project kept the direct communications code very similar.

Thanks.

[slacko]

Hi everyone,
I did my first purchase on Adafruit, a Nokia 5110 display.
Apparently I have the same problem: when trying to wire the display to my Arduino 2009 as in the tutorial (using the 4050) I just got a really bright backlight but nothing actually displayed on it when running the pcdtest.
This is happening also if I wire it directly, without the 4050 and playing around with the contrast.

Here are the pics of my wiring. any help?

[adafruit_support_bill]

You have not soldered the header to the display. You have to solder the header to get reliable electrical contact for the control signals.