Hi everyone, i buy an LCD like this LCD 2.8 TFT 240x320 v1.2 and I have an Arduino Mega, I downloaded the library UTFT from here and follow the connections guide from there but my LCD dosnt show anything, in the example code from the library I probe almost every driver for an 2.8 LCD but still dosnt work.
I attach the image with the connection guide I use for the Arduino Mega.
Please Any idea of what may be going wrong?
Thank you.
Your 3.3V display has 20x2 header pins. If you connect directly to a 5V Mega2560, you will damage it.
Buy a Display Adapter like this
There are several Adapters available for a Mega. These contain the necessary 5V to 3.3V level shifters.
There is only the CTE/Sainsmart Adapter for a Due. This does not have/need level shifters.
If you are using UTFT, you need this "model":
#define ILI9325D_16 5 //i.e. informative name
or if you like the UTFT-style of gobbledygook name:
#define TFT01_24_16 5 // ILI9325D (16bit)
David.
Ok, I understand the display have 3.3V logic, Im going to get the adapter, in the meanwhile Im going to try using some level shifter IC i have here, thanks for the help
Hi, I use some CD4050 for the connections between the screen and the Arduino Mega but still doesnt work, I checked every connection and tested some drivers in the library code, after this I test another brand new lcd in case if the first screen was damaged but the result is the same doesnt work, Im going to check again the connections and test again.
From memory, the 4050 has got six channels. So three 4050 could be used for the TFT.
The display should work fine if you provide the correct 3.3V signals. (assuming that you have not already damaged it with 5V)
Post a schematic AND a photo of your actual wiring.
Personally, I prefer a display shield that plugs directly into the Arduino.
The Adapter Shield means you have a 3-piece sandwich with the display module only secure at the header end.
Any homegrown 4050 solution involves a lot of hand wiring on a breadboard. Very risky.
If you use soldered headers and wiring on a Protoboard it can be reliable.
David.
Hi, yes the 4050 has six channels, I used four 4050 because I need 20 pins (DB0-DB15, CS, WR, RS and RST, I test my third lcd and I have the same result, the screen dosnt show anything just a white flickering.
The connection guide Im using is from the library UTFT:
and this is a picture of the lcd Im using:
In this moment I cant have access to a tft shield for the lcd, that is im using the 4050 alternative, I double check the connection and everything looks good.
Im keeping searching in the forums and documentation trying to make this lcd works.
RD must also be connected via a level shifter. i.e. 3.3V logic.
Since UTFT has no concept of reading the controller, RD can be wired directly to 3.3V.
Your 4050 is unidirectional, you would not be able to read anyway.
David.
I connect the RD pin to 3.3V directly but the result is the same white flickering, I also try again different drivers in the software but nothing happen.
Thanks
There are such a lot of unknowns. e.g. your 4050 wiring.
Can you believe the Ebay Vendor?
Does it really have an ILI9325?
Have you selected 8-bit or 16-bit mode?
Personally, I would connect it to a 3.3V board e.g. Zero or Due (which have 3.3V logic)
I would use my MCUFRIEND_kbv library to read the controller ID.
And then run it in 8-bit mode on a Zero, Due, STM32, ... or even an XMINI-328P configured for 3.3V.
The UTFT approach is pure guesswork about controller, wiring etc.
But hey-ho, it is your project.
Life is a lot simpler with a Red 2.4" Uno Shield or a Blue 2.8" Uno Shield
David.
Hey David, i double check the 4050 wiring and is ok, about your suggestions i have very limited budget and recurses that is why Im doing my best to make it work with the things I have.
Im going to read about your MCUFRIEND_kbv library and talk with the vendor about the driver.
Thank you so much for your help and suggestions.
Julian.
If you connect your 4050s correctly, they should work.
Personally, I am terrified by the thought of wiring all the 4050s to a 16-bit bus.
Post a clear photo. Other people's eyes can be very helpful.
So much simpler to use a 3.3V Arduino in the first place. No level shifters and most importantly, you can read the ID from your controller. You can read the GRAM memory.
David.
