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DT022BTFT display blanking

I have two test units, one running the DT022BTFT and another running the DT024DTFT. They are both running the same code.

The DT022BTFT display does not always function...just shows a blank screen. Or it will go to a blank screen randomly. The only difference is that this display is on a 4" extender cable which corrects pin out errors on the prototype board. Would you expect this extention to cause this sort of problem with the display?

The DT024DTFT display is not on an extension and always works as expected.

Replies

engineering_seacomp's picture
engineering_seacomp
February 4, 2019

It is possible that the 4 inch extender cable is causing signal distortion of the ground-referenced, RGB parallel data. Without a ground plane, you can't send parallel data very far without corrupting the data. You could try wrapping the extender cable in aluminum foil and connecting the foil to the ground pin of the extender cable. The foil might make just enough difference to get the display working reliably. If you have a need to extend the display cable for a product, you could have an extender cable made with a ground plane.

Another possiblity is that your extender cable has too high a voltage drop on either the VCC or ground lines. Make sure you keep the backlight LED circuit separate from the display digital power supply circuit. The backlight draws a lot more current that the display logic, so if you are sharing a VCC or GND wire with either the backlight anode or cathode pins, it could introduce a large voltage drop that would confuse the digital logic circuits.