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TFT Display Requires Button Reset After Switched Off/On
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TFT Display Requires Button Reset After Switched Off/On

by Tinkerboi on Tue Mar 06, 2018 11:19 pm

I've put a 2.4" featherwing TFT shield on a feather 32u4. I've run the graphictest and touchpaint successfully, and everything seems to work just fine UNTIL I turn the device off.

I have an SPDT slideswitch wired to the EN and GND pins per the instructions. The device turns off and on as it should, but I just get a white screen when I power it back on. No matter how long I let it sit, the sketch never reloads on the display unless I hit the on-board reset button. After that, it reloads the sketch just fine and everything works normally. Ultimately I want to put it in a case, so having to open the case and do a manual reset every time I turn it back on is not ideal.

Does anyone have an idea of why the sketch isn't automatically initializing the display when the device is turned off and on again? I haven't put any of my own code on it yet. I've uploaded touchpaint and the graphictest, and get the same results with both those example sketches.

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Re: TFT Display Requires Button Reset After Switched Off/On

by Tinkerboi on Wed Mar 07, 2018 1:12 am

Nevermind. I put tft.begin() into loop and it fixed the issue. Apparently setup() doesn't get run again after an EN power cycle? That seems weird.

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Re: TFT Display Requires Button Reset After Switched Off/On

by Tinkerboi on Wed Mar 07, 2018 2:05 am

After toying around with the example sketches, I discovered that setup() is definitely running, but that the delay(10) before the tft.begin() call is not adequate. The function fails, then nothing ever works and you get stuck in a white screen. This setup seems to need at least 106 ms to recover after cutting the power. That's why sticking it in loop() corrected it.

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Re: TFT Display Requires Button Reset After Switched Off/On

by sigilvii on Fri Mar 09, 2018 6:54 pm

Do you suppose a similar issue is causing the 'white screen of death' on the 2.2" PiTFT screens from the Adafruit PiGRRL Zero kit? (my post). Of course I recognize that the Raspberry Pi Zero is not an Adafruit Feather 32u4, but I am desperate for solutions here. I think I will try jumping the reset pins to see if that fixes my problem (screen stays white). I hadn't tried it because there isn't an onboard reset button normally.

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Re: TFT Display Requires Button Reset After Switched Off/On

by sigilvii on Tue Mar 13, 2018 10:29 am

sigilvii wrote:Do you suppose a similar issue is causing the 'white screen of death' on the 2.2" PiTFT screens from the Adafruit PiGRRL Zero kit? (my post). Of course I recognize that the Raspberry Pi Zero is not an Adafruit Feather 32u4, but I am desperate for solutions here. I think I will try jumping the reset pins to see if that fixes my problem (screen stays white). I hadn't tried it because there isn't an onboard reset button normally.


UPDATE: doing an onboard reset did not help with anything.

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Re: TFT Display Requires Button Reset After Switched Off/On

by Tinkerboi on Tue Mar 13, 2018 10:54 am

You may want to post the code you're trying to run back in your thread.

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Re: TFT Display Requires Button Reset After Switched Off/On

by sigilvii on Tue Mar 13, 2018 11:06 am

Tinkerboi wrote:You may want to post the code you're trying to run back in your thread.


Thanks for your reply, Tinkerboi. I'm not actually running any special code. It's just the image put together for the PiGRRL Zero. https://learn.adafruit.com/pigrrl-zero/software Maybe I should clarify this in my post.

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Re: TFT Display Requires Button Reset After Switched Off/On

by Tinkerboi on Tue Mar 13, 2018 11:31 am

Ah, yeah. I'd try that. My first thought would be the display driver isn't working, but I'm not familiar with using tft shields on a pi.

Hope you figure it out!

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