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Shield not working with 2.8" TFT
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Shield not working with 2.8" TFT

by Mongo56 on Thu Jan 07, 2021 9:32 pm

I just received the Adafruit Proto Shield for Arduino Unassembled Kit - Stackable - Version R3
PRODUCT ID: 2077

I'm using a 2.8" tft and everything seems to be working except the display itself.

The integrated SD card is working, but the display only shows a white screen.

I've ohmed out all the pins for shorts, and power, and everything tests out good. No shorts between pins, and good 5vdc, vin, 3.3vdc, and good ground.

Any suggestions? Everything works great connected directly to my arduino mega 2560.

Thanks!

Mongo56
 
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Re: Shield not working with 2.8" TFT

by adafruit_support_mike on Thu Jan 07, 2021 10:00 pm

Post a photo showing your hardware and connections please. 800x600 images usually work best.

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Re: Shield not working with 2.8" TFT

by Mongo56 on Fri Jan 08, 2021 9:46 pm

What angle do you need to see? I took seven photos, but seem to be limited to three uploads.

The one photo shows it working without the shield. The other two show the left and right sides with the shield connected.
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20210108_160856.jpg (112.57 KiB) Viewed 143 times

Mongo56
 
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Re: Shield not working with 2.8" TFT

by adafruit_support_mike on Fri Jan 15, 2021 3:51 am

Hmm.. that’s a strange one.

The way you’re using it, the signals from the Arduino should pass directly through the stacking headers to the display. The Shield shouldn’t have any effect at all, unless you’ve made some connections on the Shield that interfere with the display pins.

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Re: Shield not working with 2.8" TFT

by Mongo56 on Mon Jan 18, 2021 5:33 pm

adafruit_support_mike wrote:Hmm.. that’s a strange one.

The way you’re using it, the signals from the Arduino should pass directly through the stacking headers to the display. The Shield shouldn’t have any effect at all, unless you’ve made some connections on the Shield that interfere with the display pins.


Strange indeed. Nothing has been done other than plug the shield onto the Arduino. I did add all of the caps, resistors, and leds, but they all test good. No modifications or extraneous connections. I have ohmed out every pin to it's neighbor, power and ground. Everything rings true. I have ohmed out every pin to every other pin (very time consuming), and there are no shorts or open connections, where there shouldn't be. All connections for power and ground are connected and ring true. It makes no sense at all.

I know DOAs happen and it's not a reflection on the product as a whole, but it does make me reluctant to give it another try.

Mongo56
 
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Re: Shield not working with 2.8" TFT

by adafruit_support_mike on Mon Jan 18, 2021 10:02 pm

Do you have anything connected to the Proto Shield other than the display?

Also, to confirm, does the display work with the same Arduino running the same code if you take the Proto Shield out of the middle?

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Re: Shield not working with 2.8" TFT

by Mongo56 on Mon Jan 18, 2021 10:28 pm

Nothing but the display shield is connected to the proto shield. Everything else is wired to the Arduino digital pins 22-53 and the second set of I2C pins that are down by digital pin 22 and the 5vdc pins.

Yes, everything works without the proto shield, as shown in the photo I posted previously. The code and everything work fine without the proto shield. With the proto shield, everything but the display shield works. Serial monitor is displaying everything as it should, but no display on the TFT display.

Mongo56
 
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Re: Shield not working with 2.8" TFT

by adafruit_support_mike on Tue Jan 19, 2021 5:17 pm

Weird, but thank you for confirming it.

My only remaining concern is that the Proto Shield might be making some kind of unwanted connection between pins on the Mega that behave differently than pins on an Uno. If that’s the case, replacing the Proto Shield wouldn’t fix anything.

The best way to test that would be to connect the TFT to the Mega with jumper wires, then move the jumpers to connect through the Shield one by one. At some point, changing a connection should make the TFT stop working.

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Please be positive and constructive with your questions and comments.