63-NHD7080FTCSXNCTP TouchScreen Stopped responding (arduino w/shield)



  • mike_s


    I looked over the Arduino and FT81x schematics, the FT81x shield gets ALL of it's power from the arduino power header, so you absolutely MUST use a good DC power supply for that arduino DC jack.  (USB definitely does not have the current capability to power everything)

    you ONLY need that one single source for your power, that DC jack on the arduino, but you must use a good supply, go for 1000mA or better....

    sounds to me from your heat problems and voltage readings your power supply is too weak, and in the other experiments you were shorting two power supplies together...

    1) You may want to try and 'isolate' your problems if possible, as you may have damaged your screens initially when you were breadboarding them, before you got the FT81x shield..

       a) disconnect the TFT from the FT81x shield, and just power up the Arduino + FT81x board together, make sure they stay on and you feel ZERO
           heat anywhere...

       b) measure voltages on those connectors (ie still without TFT) and verify voltages are 3.3 and 5.0, ie they should NOT be lower..

    *** ALL of this to be done with  GOOD DC POWER SUPPLY (1000mA or better) into that Arduino DC jack ONLY ***
    (do not apply power directly to anywhere else)

  • ironhydroxide

    The power supply (wallwart) i'm using is a 3A 9VDC capable supply.

    I've used this same arduino in other projects before this, and have since confirmed that the arduino does not have issues when NOT used with the shield/running the screens.

    I'm very unhappy with the quality of these screens.
    Thinking I did something wrong I ordered another 4.3, and a 7" resistive touch.

    The 4.3 crapped out in the exact same way as the previous 4.3 (massive heat from the chip on the tft module).
    The 7" resistive has stopped responding to any touch... just as the Capacitive did.

  • Ted M.
    NHD Staff


    Sorry to hear you are having some trouble getting the EVE2 TFT display working properly.

    When using the NHD-FT81x-SHIELD, it is only necessary to power the Arduino itself with the 9v to 12v and 3Amp DC wall supply. 

    Do not power the EVE2 TFT pins with a separate 3.3v supply in this case. 

    Using a 12v supply for the Arduino may be necessary if the 20 pin interface cable is longer than 8" to 10" or if you have other devices connected on the 20 pin interface cable or SPI bus. 

    It is ok to keep the USB programming cable connected to the Arduino at the same time as the DC supply for convenience in programming and testing simultaneously.

    The Arduino Shield will supply 5v to drive the backlight voltage booster circuit on the EVE2 PCB so that chip will be cooler as it will produce up to 26v to drive the LED's for the backlight depending on the TFT display connected.

    Best Regards,

  • ironhydroxide

    OK, after everyone says my power supplying the Arduino was the problem, I took a 12V 20A supply and wired a bullet connector on it.

    Powering JUST the Arduino, with the shield (https://newhavendisplay.com/arduino-shield-to-interface-with-ft81x-eve-tft-modules/) connected to Either of my 4.3" screens (https://www.newhavendisplay.com/nhd43480272ftcsxnt-p-9568.html) with the FFC from NHD (https://newhavendisplay.com/20-pin-flat-flex-cable/) I get one flash of backlight as soon as the power is connected, then no response. If left connected, both will begin to heat the FT812 Chip to untouchable temperatures. 

    When I try my 7" displays (https://www.newhavendisplay.com/nhd70800480ftcsxnt-p-9576.html) and (https://www.newhavendisplay.com/nhd70800480ftcsxnctp-p-9575.html) of course changing the compiled code on the arduino to match the 7" and Capacitive or Resistive touch. The screens actually light up and show the initial calibration "touch a point", but both refuse to respond to touch input and will not progress past the "touch a point" stage. 

    I believe the issue was/is that my 9V 3A walwart must have some voltage drop due to not large enough conductors in the cable, thus causing some voltage drop or amperage limitation.  Now that I've gone nuclear on it (12V 20A) the 2 larger screens seem to try, but still do not respond to touch.


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