Today, my screen with an ST7796s controller arrived. It looks exactly like this one here: 3.95inch Arduino Display-UNO - LCD wiki
On the label, it says ST7796s Driver and Bus 8Bit. I plugged it onto my Mega2560 as displayed on the link above.
I downloaded the MCUFriend_kbv lib (version 2.9.9) from the Arduino Library Manager. Then, I made the following modifications to the library:
The "graphicstest_kbv.ino" sample project reports an ID of 0xD3D3, so I forced the ID to 0x7796.
But it only shows a white screen, nothing else.
What I tried is to download MCUFriend 3.0 from github (no luck either) and I tried USE_MEGA_8BIT_PROTOSHIELD and USE_MEGA_8BIT_PORTC_SHIELD (also, no luck).
[tt]Not using "[color=#643820]USE_SPECIAL", [/color]the display reports an ID of 0x0 which seems to mean that the display is write-only.[/tt]
Any help is highly appreciated!