Sharp Memory Display 2.7" not working anymore

[Matthew98]

Hello,

I just got my Sharp Memory Display 2.7" (Part ID: 4694) yesterday in the mail but it stopped working later that evening. I'm using an Itsy Bitsy M4 with the Arduino IDE and when powered on, it displays a bunch of little random lines instead of the test program provided with the Arduino library. It was working before and running the test program just fine but I looked over and it started doing this. It retains the lines even when powered off and unplugged from the breadboard for 30ish seconds, which I thought was weird. I tried using another microcontroller, but it displays the exact same thing. I am certain the connections are right and I still get 3.3V on the 3.3V output pin on the breakout board. The screen will update and change with the test program but it just displays a bunch of little lines. Looking at the schematic for the breakout board, I'm wondering if it has anything to do with the level shifter (74HC4050D) since the SPI signal goes through that chip and it seems like the signal is getting scrambled. Is it possible to fix this or can I get a replacement screen? I've attached various photos of the display to help illustrate my problem. Looking at the forum, I think my issue is similar to this post from 2018 viewtopic.php?t=131522

Please let me know if you need any more pictures or information.
I appreciate your time!

Display Opperation

20221203_170414 (1).jpg (507.27 KiB) Viewed 65 times

What is displayed when the code is running through the example program. It will change as the program progresses but this is the gist of what is displayed.

All pixels on command

20221204_170753 (1).jpg (395.4 KiB) Viewed 65 times

This is what is displayed when writing code to turn on all pixels.

Microcontroller Wiring

20221204_165917.jpg (387.88 KiB) Viewed 65 times

My wiring from the Microcontoller to the display. Solder joints all look good as well.

[mikeysklar]

It is a good sign you had it working (briefly).

Are you still running the sharpmemtest example? Have you modified it at all?

https://github.com/adafruit/Adafruit_SH ... emtest.ino

Does gently pressing the display near the header pins change anything?

[Matthew98]

Hello!

Thank you for your reply! I am using the sharpmemtest example. The only thing I changed with it is the SPI pin numbers and the number of pixels to match that of the 2.7" display. Please see my code snippet below.

In a surprising turn of events, I plugged it back in after leaving it unplugged while I was at work and it seems to be working again! Not sure how as I didn't touch it at all and it's running the same code. That does make me a little concerned it may stop working again in the future. I've never had a screen die on me then come back to life before, so this is new territory for me as to what that means for it's lifespan. Any ideas as to why this happened?

I appreciate the help!

Code.PNG (33.34 KiB) Viewed 56 times

[mikeysklar]

There was a related issue in the forums and the display working and then not working until power was removed. That one turned out to be a memory related problem specific to smaller boards like the UNO. It does make me wonder if the demo creates a memory leak scenario. Maybe you should try coding the application you had in mind?

viewtopic.php?p=728905

[Matthew98]

Interesting! I bought the display mainly to play around with and use in a potential future project, so I don't have any code to try as of now. I did however play around with the example code. I added some more functions and altered the existing ones. I had no issues when doing this and the display seems to be working still. That being said, it makes me a little nervous that it may stop working later in the future after I put the project on the back burner.

One thing I was able to figure out was if you change the size of the display to anything but 400 by 240 in the code, it gives very similar results to what I was experiencing before. Not sure how that would have changed on its own but I guess that is a possibility. That theory has a little more credence given that the default value of the example code has it set to 144 by 168.

Display Resolution Line

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