wire a 3.2" 240x320 tft color screen to a mega 2560 r3

Bonjour
Hello everyone.
j try to connect a 3.2" 240x320 tft color screen to a mega 2560 r3
I took my courage by my claws and I threw myself a second time.
Here I am asking for your help. Here’s my idea and I hope that someone will guide me.
Thank you very much.

Would it not be much easier to buy a proper 3.3V Arduino e.g. Zero or Due?

No you should NOT connect a 3.3V pin to 5V
You connect a 3.3V pin to the 3.3V header socket on your Mega.

Yes, your potential dividers will work. But you are putting a large-ish load on the Mega. Your resistors could have higher values.

David.

thank you for your response
if I could connect them directly, yes, and if that's impossible with the mega
only I already have the mega and the resistances.
You say we'll have to raise them, but by how much?
as far as the power supply is concerned I have a pc power supply that can output 12v 5v and 3.3v so I can power from 3.3v. if that would work
thank you

The backlight takes too much current for the Mega2560 3.3V header socket.

But the logic signals will be fine with your resistors. I was being pedantic about the values. 1k8, 3k3 only take 1mA per "HIGH". Another reader in another thread was using 200R and 470R which are unwise values.

David.

Please be patient.
So is it worth it if I feed the 3.3v directly into the 3.3v of the pc power supply?
and 1mA's insufficient in"HIGH" mode.

Logic signals for CMOS chips require microAmps not milliAmps.
Even if 20 logic signals are "HIGH" it is only 20mA. The Mega2560 is fine.

The 3.3V header socket on a Due can provide up to 500mA. i.e. sufficient current for the backlight (50 - 80mA)
The 3.3V header socket on a Mega can provide up to 30mA i.e. not enough for the backlight.

David.

Thank you
what is needed is more a due than a mega but is there a way to use the mega with a covert processor or a component like that?

Thanks again.
I'll read up on it and maybe come up with an idea.

The display has Arduino written on it, and one should assume that there are saner ways of using it than you propose. I hesitate to buy deeply into this circus, but it rather looks like an absurd exercise in re-inventing the wheel, and I think you should look at finding a shield that enables the display to be plugged straight into a Mega.

Nick_Pyner:
The display has Arduino written on it, and one should assume that there are saner ways of using it than you propose. I hesitate to buy deeply into this circus, but it rather looks like an absurd exercise in re-inventing the wheel, and I think you should look at finding a shield that enables the display to be plugged straight into a Mega.

Ebay sellers plaster "Arduino" over random items. It does not mean Arduino approval.

Yes, the display can be used with a Due. But it is a lot of jumper wires.
Yes, the display can be used with a Mega. An awful lot of resistors. A separate 3.3V regulator.

From the photo it looks as if there is a LDO regulator chip on the pcb.
You would need to do your own detective work i.e. create a schematic from the pcb traces.

Life is much easier when you buy a ready-made Shield and learn how to plug it into a ready-made Arduino. Adafruit, Waveshare, Seeed, ... design shields properly. Mcufriend design badly.

David.

This is just a particularly dumb red herring. "Arduino approval", whatever that might mean and don't ask what the evidence of it might be, is not a prerequisite for successful operation in an open architecture world.

https://www.ebay.com.au/itm/TFT-SD-Shield-for-Arduino-DUE-LCD-Module-SD-Card-2-8-3-2-inch-Mega-2560-R3/271817887764?hash=item3f499bd014:g:m7sAAOSwstxVEs-u

is an intermediate shield that I have had for years, and is still around. It has to be worth a look as the pinout supplied looks like the display will fit - plug-in 'n' go, and all this jumper, resistor, and PCB tracing stuff is just arrant nonsense.

I agree 100%. Buy an Adapter shield that accepts 32-pin displays. It is your responsibility to compare pinouts for compatibility.

Punters are determined to wire up 50 resistors by hand (and correctly). And provide a suitable 3.3V supply.

You can buy a ready-made display shield as cheaply the Adapter.
Or buy the Adapter to suit your 36-pin display.
Or hand-wire a lot of resistors and a regulator.

The main attraction of Arduino is that it requires software ideas without technical hardware knowledge.
But you can concentrate on the hardware side if that is what you prefer.

David.

Good evening
I hope health and prosperity for and for everyone.
I apologize for the delay, I found this shield at 30 euros near me home delivery I will buy it if you confirm it.
I believe that the ili9341 and tft library manage this module.
See you later.
thank you so much
Notice: attached the image of the shield & screen

That is the shield to which I was referring, and a suitable end to a thread that should never have happened. The supplier should have a comprehensive wiring diagram and the shield should come with additional headers. Note that, if you want to use the SD slot, you need to bridge one of the jumper points. The Henning Karlsen library from RinkyDink will probably work with your display. It is very well documented.

Hello
Thank you for the confirmation and also your explanations
Why a thread that should never have arrived? This is how we learn. We ask the silly question and get the right one from someone like you.
The supplier must have a complete wiring diagram and the shield must be delivered with additional headers. Note that if you want to use the SD slot, you must connect one of the jumpers. RinkyDink's Henning Karlsen library will likely work with your screen. It is very well documented.
thanks again
Have a good day

FaridEr:
This is how we learn.

I take your point, but the thread was too long.

Nick_Pyner:
I take your point, but the thread was too long.

The OP provided the correct information i.e. his actual screen. his proposed wiring.
And his desire to avoid an Adapter shield.

He received accurate replies:
3.3V Regulator chip instead of wiring 3.3V pin directly to 5V supply. Potential dividers are fine for 5V logic from Mega2560.

Or use Zero, Due which have adequate 3.3V power and no need for resistors.

The conclusion was:
CTE Adapter Shield with 32-pin header socket.

The main thread was conducted over 24 hours. Successful !!!

The CTE Adapter might take 28 days to arrive.
The OP could solder a regulator, header strips, lots of resistors onto some Protoboard in an hour or two. He already has the resistors.

I think that this is an example of the Forum working well.

David.

FaridEr:
Here's my idea ...

david_prentice:
And his desire to avoid an Adapter shield.

Really? I didn't see any desire to avoid a shield, he just had an idea, and it was a particularly bad one. Indeed, and quite the opposite, I rather feel OP simply didn't know there was a shield to "avoid".

Fortunately, about the best thing to come out of this circus is that the poor OP apparently realises how silly the question was.

Hello
David is right
Really I wanted to avoid buying a shield, I had an idea, which was not bad but simply I was trying to find a cheap solution and if it works it will be good for everyone.
I wonder why a DIY solution is impossible.
I order the shield + screen but I document myself every day if
I get there or someone finds a handmade solution.
See you. Thank you

FaridEr:
I wonder why a DIY solution is impossible.

OK. It is definitely not impossible, but it is very silly.