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Thread: teensy 4.0 and Ili9341 2.8"

  1. #1
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    teensy 4.0 and Ili9341 2.8"

    Hi All .. I have a 2.8" screen and have it running Some of the examples fine with the ili9341_t3 Library ..

    I connect the pin 11 MISO Line from the Teensy 4.0 to T_DIN of the ILI9341 board .. Im left with a blank white screen ...
    Not sure whats happening here ..

    I had purchased 2 some time back and just started using the second one, first one ran fine no issues touch and all ..

    Same code as the first no changes .. eg demo code ..

    I had some custom code running and the first screen ran fine no issues touch as well ...
    when I swapped the displays out , the second display with the MISO issue would not run ...

    am I missing something ? This is the only line thats causing me problems and I'm stumped....

    Thanks in advance

  2. #2
    Senior Member+ KurtE's Avatar
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    Hard to say without seeing pictures.

    I assume when your: 11 MISO(Master IN Slave Out) you are meaning pin 11 which is MOSI (Master Out Slave In), Pin 12 is the MISO pin.

    Also not sure from your description, were these purchased from PJRC? https://www.pjrc.com/store/display_ili9341_touch.html

    Note: with some displays, I have had better luck if I hook up a reset pin to an IO pin instead of 3.3v and then pass the pin number to the constructor

  3. #3
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    I have a bunch of ili9341 displays and several of them have this issue. One will go white screen after 15-20 minutes of use. I think it's heat related though haven't spent enough time to track it down specifically. Another has a startup issue. Half the time it shows a white screen, sometimes power cycling it fixes the problem. The one I have from PJRC doesn't exhibit the problem. Be aware that stuff sold cheap on ebay/amazon/aliexpress/... are often rejects. Usually it's just cosmetic but you never know what you will get.

  4. #4
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    yes I'm wired identical to the pinout you linked to at PJRC .. Both were purchased from PJRC
    .. but I had not opened it up as I didn't need it at the time ... as a matter of fact I just ordered 2 more from PJRC as well as some teensy 4.1's .. if its a display issue I should have reported it when I received them .. my bad...

  5. #5
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    Well the only other display I've purchased to date is a 5" ra8875 from buydisplay .. other then that its the ili9341s .. good display ! .. easy to use and code up ..

    Anyhow , my ordered ili9341s should be here in a week or 2 ...

    I can pull my working ili9341 out of the other project in the meantime ..

  6. #6
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    Okay update .. I reset the teensy 4.0 back to day 1 ..reconnected the line, re-loaded the graphics test and now its working ... I had to turn it on and off a few times to make it happen so its intermittent ...must be something to do with powering up .. anyhow ..I'll have to investigate this ..I'm running off usb right now so there's some glitch happening or I have bad power .. if I power cycle it sometimes its there and sometimes its a white screen ... Well at least I know its not the display ... some sleuthing is required lol

  7. #7
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    Hi Keith I have similar issues, but only with the ILI9431_t3 library.
    When I switched to the Adafruit_ILI9341 library everything works fine.

  8. #8
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    thanks SkipBerry .. I'll switch over and give it a shot just to see what happens

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