Issues wiring TFT display ILI9341 (in 8bits mode)

Hey guys,

I ordered some TFT screens 320x240 controlled by an ILI9341. it’s all mounted on a shield (but not the standard 4wires shield).

I ordered with the following configuration :

  • Power supply 5V(logic remains 3.3v)
  • 8bits mode

there is on it an SD card by default, and I choose no font chip and no flash chip.

Unfortunately I’m not able to get it working. :confused:
I do not expect the library to be the problem here because it work in simulator. So I think I’m making something wrong with the wiring.

I’m really new in electronics and if someone with more experience can help me figureout where I’m wrong it will be nice.

I upload a connection diagramm I got from the supplier, and here the first doubt, we can see that data lines are pulled up at 2.8v (I suppose it is that way to read from the controller). Do you think it represent an internal pullup from the ILI or I have to wire it? secondly, with the resistor I have I can only make 2.7v (using resistor voltage divider) do you think it should be good enough?

Since I’m using a Mega, I’m using few logic level converter to apply a logic at 3.3v on the display. I checked the voltage on all the lines of the logic converter and they are all working.

I tried the connect only the display related pin, I tried to connect other chip select pin to 3.3V, I can’t control it, I only got a white fullscreen.

Thank you in advance,
Maxence.

Post a link to the actual screen that you have bought. e.g. Ebay sale

Post a schematic of the actual wiring i.e. actual integrated circuits with part numbers. actual Arduino digital pin numbers (or header socket locations)

You have posted a “wiring diagram for a 3.3V Chinese 8051 chip”
This is nothing like 5V Mega2560 board.

David.

Hi David and thank you for answering.
here is the actual hardware : ER TFTM028-4

The diagram I posted is indeed not a arduino mega, but I supposed it can be use to reproduce the same connection on my arduino.

Maxence.

No it can't.

Draw a proper schematic. Pencil is fine. Post a photo.

BuyDisplay sell Adapter shields for many of their displays e.g. here
Buy the correct adapter and plug into your Mega2560.

David.

I can't find shield with 8bits mode for arduino, only SPI (4wires).

I'm drawing the schema and I will upload it when it's done.

Thanks.
Maxence.

Their Adapter shield can do 8-bit interface if you solder the extra i.c.s

David.

David,
here is what I have done. I don"t have reference for the chip on the level converter shield, but here is the link : LLC

I will check the adapter you are speaking about but what I have is the shield with the extra soldering I think. (see picture)

Thanks !
Maxence.

It looks a lot of hard work. You can mount everything on a Protoshield.

But quite honestly, buying the EastRising Adapter shield looks a lot neater.
Check your display pinout with the ER Adapter docs.

It looks like you only need to mount two LVC245 chips and a 18x2 male pin header.

David.

At the beginning I did not wanted the shield because of the SPI. I made some simulations based benchmarks and 8 bits mode was way faster to draw a full size bitmap from sd card. Unfortunatly I did not see that I was able to modify the shield in order to use it with 8bits mode.

Just to be sure, did you mean that my diagram should work ? I don't have any experience in electronic so far, for me level converter should do the trick.

also do you know if I have to connect all the chip select pin ?
my opinion : since I don't use the onboard sd, font or flash, and since all of them are related to SPI and I2C protocol, my opinion is that I don't need to define the chip select. can you confirm ?

thank you again for your time.
Regards,
Maxence.

If there is no Font chip, or no SD card, ... there is no need to provide any external pullup resistors on their respective /CS pins.

But it is good practice.

I am not a hardware expert. I certainly would not trust myself with hand-wiring your electronics.
You have to make good soldered joints between the right pins.
Life is much safer with a commercially built pcb that has been well designed and tested.

David.