What voltage is required for this 2" TFT display?

Other Hardware Displays
1

Hi!

I just recieved this 2" TFT ST7789V OLED display from AliExpress that I plan to use with an Arduino Uno or Mega 2560, and I can't figure out what voltage I'm supposed to supply to it.

https://www.aliexpress.com/item/1005006852580250.html?spm=a2g0o.order_list.order_list_main.59.79691802eyawZ0

I also found this document from a manufacturer of said display.
https://goldenmorninglcd.com/tft-display-module/2-inch-240x320-st7789v-gmt020-02/

Due to my lack of knowledge in this area, I dont really understand what this document states, as they have listed several different voltages. In the general information it lists 3-5V, yet in the specs, 5V is never mentioned (closest is 4.6 on maximum rating). The 3.3V range however, is listed several times.

On the display I bought, there are several resistors soldered to the backside of the PCB. I have seen similar displays both with and without those resistors. Are they part of an integrated circuit to downstep the voltage from 5V to 3.3V, so I don't have to?

Thank you for any help with this, I'm completely new to the use of displays with Arduino, so any information is greatly appreciated!

2

This is why you purchase from a known supplier. It is important you have the information you need to build your project. Contact the seller and ask for the needed information.

1 Like
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Thank you for letting me know, I will do that! Like I said, I have little to no knowledge when it comes to these displays. I guess I could start with resistors to drop the voltage to 3.3V as for now, and see if it works. I was just hoping to skip the extra work of doing so. Do you mind giving me some names of suppliers that I could use in the future? Thanks again!

4

I would start with 5V.
Reasoning:

  1. Every TFT LCD display I've seen has been 5V.
  2. At 5v you are unlikely to damage anything. i.e. if it does require a higher voltage then at 5V it may not function but it won't be damaged.
5

And had level converters on board?
From my experience, these are rather the exception than the majority.

Ok, quite some have an LDO on VCC, but the data lines are for 3.3V without level converters.

6

Good point, I should have added the signal inputs and outputs are usually 3.3Vdc.

7

Ok, so if I get this correctly, the VCC can be 5V, but all the other data pins needs to be converted to 3.3V? I.e. the scl, sda and so on?

8

Yes that is a common configuration and shouldn't damage anything if it isn't correct for your display.

Just a note:

Very very few devices need to be powered by 3.3v. Even if the first thing the board does is drop the 5V to 3.3V. 5V is the defacto standard for pretty much any hobby processor board or attachments. Even breakout boards for 3.3v sensors have a 5V to 3.3V regulator.

9

Thank you so much! At least now I have something to work with!

On the circuitry on the backside of the PCB, it seemes every pin connection (except vcc and gnd) runs through both a diode and a resistor. Do you have any idea what this circuit does? I've browsed through several displays before buying this one, and it is one of the few with resistors visible. Maybe I could measure them and calculate the output voltage to see what voltage is supplied to the display if I hypothetically added a 5V input... I wish I had a proper datasheet for this.

Thanks for all the help and info, I really appreciate it!

10

Maybe the same as I have one. It is for 5V. The diodes are series pull-downs, the resistors are pull-ups to 3.3V. Check if yours is the same.

Yes, according to the picture on the linked page.

11

Yes, my display is identical to the picture in the link!

Thank you so much! From now I will make sure to check if devices have all the info I need on them before buying in the future!

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