ILI9488 and teensy 4 and touch 2046 and ILI9488_T3

[Keith_M]

Okay .. this is just an observation of which I'm totally puzzled . I purchased 2 X ili9488 from the same vendor ... both displays work fine . I did have to drop the MISO line off the display portion in order to make the touch and display work concurrently.. I initially used the same pinout as the ILI9341 as on the PJRC page .. So when I used 1 display with CS for touch on pin 8 of the T4 and IRQ for touch on pin 2 of the teensy .. ! display worked fine .. When I swapped the second display for the first , touch failed to work. I ran up serial monitor and low and behold touch was unresponsive..

pretty puzzled..

So jokingly I moved the touch CS pin over to pin3 and left the touch IRQ on pin2 , changed the CS pin in the code ... BANG! display works perfectly ...!!! (with miso line disconnected from the display portion)

Can anybody shed some light on this ? .. My project is moving forward fine , but the behavior I find rather puzzling and I've had not had the time to go back and look at it .

cheers!

 

[mborgerson]

My first guess would be that the second ILI9488 board isn't properly tri-stating the MISO line. Looks like a problem needing an oscilloscope.

 

[Keith_M]

My first guess would be that the second ILI9488 board isn't properly tri-stating the MISO line. Looks like a problem needing an oscilloscope.

That's what I thought as well .. and there is a history of that with this display ..

BUT I can't figure out why the one that doesn't tri-state correctly on pin 8 can function properly when I move the CS line to pin 3 .. That's what's throwing me off.