White screen when using Adafruit ILI9341 library

Other Hardware Displays
1

Hello!

I recently bought this ILI9341 board from AliExpress. In the reviews nobody seemed to have a problem with it.

However, when I try the Adafruit ILI9341 library, I only get a white screen. I tried also putting the data pins through 1K resistors, but it did not change anything.

Most interesting part is that I tested it with Adarfuit ST7735 (just for laughs) library, it seemed to work better. It did not 100%, but some artefacts could be seen from the graphics test. More than a white screen at least. This led me to think that theoretically the display should work, just a problem with the library.

Would be grateful for any help :slight_smile:

2

Assuming you are using an UNO:

UNO +5V to display pin 1 (VCC)
UNO +5V through a 56 Ohm resistor to display pin 8 (LED)
Typical connections are:
UNO 0V (GND) to display pin 2 (GND)
UNO digital pin 7 through a 1K2 resistor to display pin 4 (RESET), add a 1K8 resistor from display pin 4 to GND
UNO digital pin 8 through a 1K2 resistor to display pin 5 (DC/RS), add a 1K8 resistor from display pin 5 to GND
UNO digital pin 9 through a 1K2 resistor to display pin 3 (CS), add a 1K8 resistor from display pin 3 to GND
UNO digital pin 11 through a 1K2 resistor to display pin 6 (SDI/MOSI), add a 1K8 resistor from display pin 6 to GND
UNO digital pin 13 through a 1K2 resistor to display pin 7 (SCK), add a 1K8 resistor from display pin 7 to GND

It is important to include the 1K8 resistors to GND with this 2.2" display as otherwise it will not work. The 1K2 and 1K8 resistors are a "potential divider", acting as a logic level shifter so that the logic level at the display is reduced from 5V to around 3V. Pin 9 of the display does not need to be connected up.

3

bodmer:
Assuming you are using an UNO:

UNO +5V to display pin 1 (VCC)
UNO +5V through a 56 Ohm resistor to display pin 8 (LED)
Typical connections are:
UNO 0V (GND) to display pin 2 (GND)
UNO digital pin 7 through a 1K2 resistor to display pin 4 (RESET), add a 1K8 resistor from display pin 4 to GND
UNO digital pin 8 through a 1K2 resistor to display pin 5 (DC/RS), add a 1K8 resistor from display pin 5 to GND
UNO digital pin 9 through a 1K2 resistor to display pin 3 (CS), add a 1K8 resistor from display pin 3 to GND
UNO digital pin 11 through a 1K2 resistor to display pin 6 (SDI/MOSI), add a 1K8 resistor from display pin 6 to GND
UNO digital pin 13 through a 1K2 resistor to display pin 7 (SCK), add a 1K8 resistor from display pin 7 to GND

It is important to include the 1K8 resistors to GND with this 2.2" display as otherwise it will not work. The 1K2 and 1K8 resistors are a "potential divider", acting as a logic level shifter so that the logic level at the display is reduced from 5V to around 3V. Pin 9 of the display does not need to be connected up.

Thanks a lot, it's working now! However, I still cannot manage the SD card to work for bitmap image displaying. I tried to connect the MISO to UNO pin 12 and SD_CS to UNO pin 4, but it still says "Initializing filesystem...SD begin() failed" in the serial monitor.

4

Have you put a potential divider on the SD_CS pin too?

5

david_prentice:
Have you put a potential divider on the SD_CS pin too?

Yeah, I did that too

6

Well, everything should work 100%.

Personally, I always use 3.3V GPIO for TFT, SD, XPT2046
I would expect 5V GPIO to work ok with potential dividers (or level shifter chips)

I am sure that many readers have used these Red displays with 5V GPIO + level shifters.

David.

7

See this link, check your wiring, do not change your library, just use the wiring info. Try another SD card, large capacity ones may not work.