RA8875 + Teensy3.5 + Resistive Touch Scrren

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RogerdeValle

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I have an East Rising 5" RA8875 display running perfectly with a Teensy 3.5. When I try to use the integral touch screen (resistive) I find the Interrupt pin on the display never activates when the screen is touched.I can see the initialisation is performed as expected via touchBegin and touchEnable.
Before I replace the display I was wondering if anyone has the same configuration operating, I have done several of these before on Arduino Mega and Due and never had an issue and the library is basically the same. Any information would be well appreciated.
 
Did you check with an oscilloscope if the interrupt pin of the display works if disconnected from the Teensy (all other connections remaining in place)? If yes, it's a Teensy/Code problem, if not, it's a display problem, either a wrong software setting during initialization or a hardware fault.
 
Really hard to say without any information, like a picture showing the hookup.

What code is running. Things like: "The library if basically the same" does not help. Maybe the code has architecture (AVR or DUE) specific code in it.

Maybe the Interrupt pin is not initialized to be an Input pin. Maybe the code is not properly configuring the interrupt.... attachInterrupt(0) on an Arduino UNO will use pin 2... On Teensy it will use pin 0...

But again without additional information, just guessing.
 
I just got back to looking at this and remembered I had to alter my original RA8875 libraries, this would need to be done in the teensy supplied RA8875 library.. For the touch interrupt pin to work as expected the RA8875 has to be in the graphics mode, I added changeMode(false) (GRAPHICS) to the touchEnable() routine in the library so the mode was changed to graphics each time the touchenable(true) routine was called. The changeMode routine is a private routine in the library so there is no option but to edit the library or expose the routine. Now everything works as expected, I hope this helps some others that may have had the same issue.
 
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