Go Down

Topic: a request for a basic knowledge on using TFT screen (Read 361 times) previous topic - next topic

MigLeader

Hello fellow programmers ..... first i apologize if i sounded a beginner because i am actually a one.

i am new to the world of Arduino but i am starting getting the hang of it by self learning, but i got a problem with a startup experiment:

1:-i bought from a local store an LCD TFT screen (2.8 inch 240x320).

2:-because i am a beginner i didn't know that the model number is such important and it didn't come with a tutorial.

3:-also as you can see from the attached images , the pins is different from all the tutorials i found on the net i manged to light it up by hooking the LED pin to 3.3v (i hope its right) but can't make it display anything.

4:-so all i ask is some guides on how to start using it , maybe a chart on what pins goes to what and how to start coding it , i don't want anything complex , maybe just show some text or even make it work.

thanks for everyone who is taking the time to help me , and please forgive my lack of knowledge..

best regards

david_prentice

It looks like the regular pinout for a 40-pin 3.3V display.

By an Adapter Shield for Mega2560 (or Due).
Plug the shield into your Mega2560.   Plug your Display into the Adapter.

Run examples from UTFT library.  It probably contains an ILI9325 controller.   But it might be SSD1289 or ILI9341.

Unfortunately the Mega Adapters can't read the controller ID.   So you have to do some guesswork.

Let us know how you get on.

David.

MigLeader

do i need a shield?? because i don't have one , and i have an uno board only right now ..... can i still work with it or the shield is the only way to work with it....

thanks sir for the respond..

david_prentice

#3
Sep 13, 2017, 11:07 pm Last Edit: Sep 13, 2017, 11:09 pm by david_prentice
Yes,  you must have a Shield because the display is 3.3V and the Mega2560 is 5V.
A Uno is 5V too.   A Uno does not have enough pins to control your TFT.

Either buy a "Mcufriend TFT for Uno Shield" e.g. like this
Or buy a Mega2560 clone and Adapter like this shield

Yes,  there are some weird 40-pin Adapters for a Uno.   I suggest that you forget about them.   There will be no spare pins for doing anything else.

The only way you can avoid the 5V to 3.3V level shifters is by using a 3.3V Due.
It is a lot of jumper wires to connect.   Much simpler with a ready made Adapter.

David.

MigLeader

ok i will try to replace it with a one suitable for my uno.

thanks a lot for your time and tips sir.

best regards

MigLeader

hi again , i replaced it with another screen , its a normal TFT 2.2 screen 240x320 , i managed to look up a tutorial on the internet on how to hook it with arduino uno but no matter what library or code i use , there is nothing in the screen just white color.


i think the problem is with the model number being different from the library.

a step by step guide would be great.

david_prentice

#6
Sep 16, 2017, 02:43 pm Last Edit: Sep 16, 2017, 02:44 pm by david_prentice
These 2.2" SPI displays require 3.3V logic.

They are very popular.   They work very well.   There are many libraries.

The most important thing is to provide 3.3V logic signals from your Uno e.g.
1.  Use series resistors for each signal.
2.  Use potential dividers.  (e.g. two resistors per signal)
3.  Use dedicated Level Shifter chip(s)

By far the easiest method is to use a 3.3V Arduino in the first place.

But if you are very "new",   the Shields like I linked to in #3 require no electronics or soldering skill.
You just plug in to your Uno and go.    (Or any Mega, Due, Zero, ...)

David.

MigLeader

okay i want  to ask something:

do i need to do all of the 3 points you listed , or only 1 of them is okay , because i understood only number 1

my arduino uno have a 5v and 3.3v , is that okay ... also i have a power module for motors that can support 3.3v and 5v , are they okay?

the problem is i am little short on money right now as i live in a country which have high shipment rate and ordering something takes from 1-2 months (Yemen if you know about it [We have a war going]) so i have to make use of what i have.
and yes i am very new , but i have some soldering skills also little on electronics....

is there a software or website that can help me create a schematics so i can show you my wiring. 

so sorry if i am asking a silly questions ...


and thanks a lot for being so patient with me

david_prentice

You only need one method.   e.g. potential divider with 4k7 and 10k resistors.  Will convert 5V to 3.4V.
Do this for CS, D/C, SCK, SDI, RESET pins.  i.e. five 4k7 and five 10k.   You do not need a potential divider on SDO pin but a 2k2 series resistor is wise.

There are several tutorials on connecting these Red SPI displays with a 5V Uno.
Ask about your chosen tutorial.  (some are crap)

David.

MigLeader

hi again .....

ok i nearly give-up on making it work , i followed like 3 tutorials and all i see is white screen only.

even i tried the potential divider and yet no difference at all.

i followed this website for understanding the potential divider:

https://learn.sparkfun.com/tutorials/voltage-dividers

and the following attachment is the library and example i tried..

yet all i see is white screen......

TFTLCDCyg


david_prentice

It looks as if your series resistors are 5k (10k + 10k in parallel)
I can't see what resistance you have on the LED line.

It is not very easy to read the colour code bands from a photo.   It would be sensible to attach schematic.  Or at least say what values you are using.

I would expect 2k2 series resistors to work in the logic lines.   And 47R for the LED.
The most important point is:   Use RST pin in class constructor.

But the neatest solution is to make an Adapter with a Protoshield.   Like in TFTLCDCyg's photos.
You can buy 6-channel and 8-channel Level Shifter chips.  e.g. breadboard friendly board
Or use CD4050BE as in #10.

Personally,   I just run the MCU at 3.3V.    But I have made adapters to receive common Ebay displays with Protoboard.    I have sockets to receive the SD pins.   After all,  there is little point in having a SD without using it.

David.

Go Up