CTE 5.0" TFT display problem


I have arduino MEGA + shield + 5.0" TFT display from Coldtears.

When I start code, at first it works ok for 2-3 minutes. Then it starts bilnking, reseting and behaves strangely-

I looped the code with while(1);, so the problem is in display (or shield), not the code itself.

Here is a short video: http://www.youtube.com/watch?v=IhV594Fzb5E

Does anybody have same display? Does it work ok? I found a guy with same problem on a 3.2 display, didn’ solve the problem.

Is this just a bad luck with bad display or those displays are not good?

Any similar alternative (5 inch, touchscreen)?

Thank you for replies!

I have one of those displays running on a Mega2560 for a few months and no problems at all with it. They do draw a lot of power though so maybe you're cooking the 5v reg on the Arduino.

Thank you for fast reply. How did not I think of this :relaxed:

It makes sense. I measured about 0.37A at usb (that includes mega board, shield+display). On mega board there is AMS1117 - which is 800mA regulator... What kind of regulators did you use?

Another problem I have is when runing demo code, it does not show text, only small text is ok on demo screen when sine and cosine signal is showing. Maybe this problem is connected to supply problems - obviously code does not read information from font IC....

I will first fix regulator and then try to fix text problem.


Could it be some kind of electrical "influence" ? What kind of device is laying direct behind the display ?

You know, all that is not shielded yet against those effects from outside...

I have arduino mega, shield and display stacked on each other.

I haven't changed the on board regulator or modified the MEGA. When working with the 5" display via USB I have it connected to a powered USB hub. This way the computer isn't trying to supply the power via the USB port. Some computer USB ports balk with a heavy load like the those large TFT displays.

When I put the project into the real world applications, I use a number of different ways to power it, depending on the situation. The most used way is with an ac/dc adaptor (9-12VDC wall wart, 1A), a bridge rectifier, and a dc/dc buck converter connected to the DC power plug on the Arduino.

The bridge rectifier ensures that polarity doesn't matter for the adaptor, the buck converter drops what ever the input voltage is down to 7.5VDC for the Arduino. If you take 9 or 12V and feed the DC jack on the Arduino, anything over 7.5 causes the on board reg to dissipate the extra voltage in heat.

Alternately I've used the AC/DC adapters that have a USB jack on them. I then just use a standard USB host cable to connect it to the Arduino's USB port.

For the text issue, or lack thereof, there are two TFT demo's. One shows a lot of graphics, whereas the other one access the text from the Font_IC and shows it. So, two different libraries and demos. The library for text examples is UTFT_CTE, the sketch is called CTE50_800x480.

Hello guys,

I solved the problem. Problem vas that backlight was drawing to much power so 3v3 regulator on mega board started to oscilate. I switched jumpers on lcd so SSD1698 internal PWM generator was driving backlight. Default value is 93% duty cycle which is sufficient to keep amperage low enough for normal operation. Now it works ok.

Thank you for participating in this thread!