Author Topic: 763-NHD7080FTCSXNCTP TouchScreen Stopped responding (arduino w/shield)  (Read 725 times)

ironhydroxide

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I bought this screen (763-NHD7080FTCSXNCTP) as well as a 4.3 resistive (763-NHD4342FTCSXNT) a while ago, and have been trying to control them with an arduino.

First I breadboarded them with 3.3v level shifters, so as to not kill the FT81X chips. but was never able to get them to properly run any of the examples found https://github.com/NewhavenDisplay/EVE2-TFT-Modules <-- Here.

Power was supplied with a 2 "channel" adjustable power supply. one at 5.1v one at 3.4v.  This powered the Uno as well as the TFT module.
In doing this I believe i killed the 4.3 somehow, as a chip on the back always gets extremely hot, and never shows anything.
the 7" flickered and didn't really act normal on almost every example, except the ones where it wouldn't show anything (not normal meaning the calibration screen came up, then goes away if you can't click dots fast enough, then the "click to play" wouldn't respond.)
I tried using a FFC with an FFC breakout in the breadboard, which gave much more erratic results than jumper wires to the IDC connector, neither was good though.
After a couple days of total frustration, I gave up for a month or so.

I then ordered the Arduino Shield (https://www.newhavendisplay.com/nhdft81xshield-p-9581.html) as well as a FFC directly from NHD, thinking that it was something I did wrong in my breadboarding or a bad batch of FFC's. 

Again, terrible results. the 4.3 will not show anything still, and the chip on the back still gets hot.  The 7" still flickers, or just cuts out after a bit.   I measured the voltage at the IDC connector while trying to power through FFC/Shield/Arduino/PowerSupply, and the voltage shown on the 5v backlight pins varied from ~3.5-4.5.  The 3.3V pins showed between 1.5 and 3v depending on if i had recently reset the arduino or not. (if the screen was actually trying to do something or not)

I decided from there to power the module directly through the IDC pins from the Power Supply, and power the Arduino through the onboard 5-12v input connector (9vdc wall wart).
This has given me the best results so far, in that a few of the examples would run, namely the "sketch" and the "graph".  Though after a little time the arduino header pins would begin to get hot (I suspect due to difference in voltage between Power supply 5v and arduino 5v regulator)

Being excited that I finally got something to work "reliably" on this, I began to try and figure out how to write my own things to the screen.  just editing the "sketch" to add background text.  should be simple.   
Soon as I upload said modification to the arduino and try to run the sketch again, touchscreen is unresponsive. 
I am unable to get past the "calibration dots" on the screen. 
I have tried uploading the UNMODIFIED example. still no response from touchscreen.
I redownloaded the examples. and uploaded fresh. still no response.

I'm so dissapointed in these things. and I don't know what I'm doing wrong with them.

Firstly, one screen dies before I can even do anything but get epillepsy from them.
Secondly, after buying more electronics, they still don't work unless I "hotwire" the remaining "operating" screen.
Thirdly, I can't seem to make much sense out of most of the examples (self taught, i don't blame NHD on my stupidity here)

Sorry for the rant, but I'm just so bummed out that these things aren't working, and yet all the reading I do online makes them seem like they are easy as setting up "blink" on the arduino.

How many people here use the arduino shield? do you have to power it separately?
Is there a different place for examples (code) that are easier to understand? (the NHD examples seem almost intentionally written to obfuscate)
Are their "courses" somewhere that I can take to learn this specific module better?

mike_s

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Hi,

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)
« Last Edit: July 05, 2019, 08:29:08 AM by mike_s »

ironhydroxide

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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

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Hi,

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,

   
« Last Edit: July 11, 2019, 10:50:55 AM by Ted_M »

ironhydroxide

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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://www.newhavendisplay.com/nhdft81xshield-p-9581.html) connected to Either of my 4.3" screens (https://www.newhavendisplay.com/nhd43480272ftcsxnt-p-9568.html) with the FFC from NHD (https://www.newhavendisplay.com/20-pos-ffc-p-1101.html) 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 wallwart 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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