Hey guys,
i have bought a 3.5“ tft display with capacitive touchscreen from buydisplay .
Now I want to connect it with an adapter board to my Arduino mega 2560. I have connected it to the Arduino as described in the datasheet for 16 bit interface.
| display |
arduino |
| IM0 |
GND |
| IM1 |
3,3V |
| IM2 |
GND |
| DB15-DB0 |
37-22 (16bit interface) |
| DB17-DB16 |
GND |
| D/CX |
38 |
| WRX |
39 |
| CSX |
40 |
| RESET |
41 |
| RD |
42 |
Backlight and power supply are also connected.
I use the library utft which is modified for the ILI9488. The touchscreen works fine with the library, but the display shows only a white screen.
I hope you can help me. Thanks.
Are you being serious?
Yes, you can solder the ribbon to your adapter. Provide twenty one level shifter channels (5V to 3.3V).
Connect to a 5V Mega2560.
Surely BuyDisplay have a suitable pcb with the level shifters. And probably with a ZIF ribbon connector.
Life would be a whole lot simpler with a 3.3V Due.
Or if you bought the appropriate Display with Mega2560 Adapter Shield from BuyDisplay in the first place.
David.
Thanks for your answer David.
In retrospect, an adapter board would have been better yes. And I can't use an Arduino Due because the other sensors need 5v.
For all connections I use the level shifter. That should fix the difference between 5v and 3.3v. Or am I wrong?
Martin.
There are proper bidirectional bus drivers. Your level shifters should work. After all, you are using UTFT which has no concept of reading GRAM or registers.
Most electronics in the civilised world uses 3.3V.
What sensors need 5V ?
Do you have more than 21 sensors?
David.
Can you recommend me a library for the ili9488 that can handle GRAM and registers?
Next to the display I use the arduino ethernet shield 2 , which need 5V. In addition, I still use two servos which need at minimum 4.8 V.
No, I don't need 21 sensors. Until now I have only the three sensors mentioned above.
Martin.
I found schematic from Google.
It looks as if all the electronics is 3.3V. So it should be compatible with a Due.
However, you can always ask your supplier to confirm this.
A lot of boards expect to be powered by 5V. You will see that the 5V often goes straight to a 3.3V regulator. All the internal logic is 3.3V. The board will often have level shifters or series resistors on the input pins like CS, MOSI, SCK. On your board there are straight connections because the W5500 is probably 5V input tolerant.
You only need to worry about connecting to a Due if there are board output pins that are 5V. Since MISO comes straight from the 3.3V W5500 chip, it will be 3.3V
Likewise, servos need 5V power but will accept 3.3V logic. Please post a link to your actual devices if you want confirmation.
MCUFRIEND_kbv can use 8080-8 or 8080-16 parallel interface from the ILI9488. It is still an awful lot of wires.
If you use the SPI interface, BuyDisplay have probably got a library. My SPI code is not for public release.
David.
Ok. Thank you David.
I'll buy an Arduino Due and try this together with the display and the MCUFRIEND_kbv library. I'd rather use 8080-16 in parallel interface instead of SPI, because according to some statements it should be faster. And with the Arduino Due and the new library the parallel interface should actually work.
Martin.