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Issue when combining Neopixel and 2.4" TFT FeatherWing on M4
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Issue when combining Neopixel and 2.4" TFT FeatherWing on M4

by therealarty on Sat Jan 19, 2019 10:31 pm

Hi,

I am building a project where I am using:
- The 2.4" TFT Featherwing (using the TFT, touchscreen and SD card)
- Neopixels, using the Adafruit_NeoPixel_ZeroDMA library, given I am using a Feather M4 Express.

When working with either the TFT, or Neopixels alone, I have no problem.
Yet, when having both running on the same script, the neopixel part seems to completely mess up the touchscreen...

To give you more details:
I am only using the native pins for the TFT FeatherWing along with PIN 11 for the neopixels.

Everything breaks when I call strip.begin();

At that point, I am not able to load from SD and display images to the Screen and the touchscreen throws endless false positives with absurd values (i.e. as if constantly receiving touch data from points with aberrant coordinates).

My guess is that there is some interference here.
When using the A5 pin for pixels, the problem seems to disappear...

Also, using a feather M0 proto doesn't produce the same issue.

I wanted to share this since it can happen to others and for the sake of it, I would love to have an explanation just to understand better what's going on.

Best regards

therealarty
 
Posts: 1
Joined: Wed Nov 11, 2015 6:24 am

Re: Issue when combining Neopixel and 2.4" TFT FeatherWing o

by adafruit_support_carter on Mon Jan 21, 2019 3:49 pm

A5 works but GPIO11 does not? Not sure why. Nothing on the 2.4" TFT wing is connected to either of those. Post full code for the example the does *not* work.

adafruit_support_carter
 
Posts: 10410
Joined: Tue Nov 29, 2016 2:45 pm

Please be positive and constructive with your questions and comments.