(SOLVED) Esp32 with Spi İLİ9481 vertical flickering banding

[lepromer]

Hello, my problem is vertical flickering banding. i using TFT_Espi and i selecting ILI9481 but i get vertical flickering banding. how can i solve this problem

[Bodmer]

If the banding moves then this suggests the supply voltage is not stable.

It is not something I have seen before.

Another possibility is that the display is not an ILI9481 since each controller has many parameters that affect display quality.

[lepromer]

İ checked Power supply and i remove Power chip and connected extrernal 3.3v to vcc, screen worked but it has vertical banding, the seller said me tft ili9481.
How can learn the chip model

[Bodmer]

Typically these displays are fitted with a 5V to 3.3V regulator, if so then 3.3V is not adequate as the regulator then drops out of the regulation zone. Check if your board requires a 5V supply.

[Bodmer]

Are you using PWM to control the backlight brightness? If so then the PWM frequency may be aliasing with the screen refresh scan. Are there any activities the software on the processor does that is modulating the screen brightness? Are you using long or short wires for power and ground?
Does the display vendor offer you different controller options, if so which ones, have you tried them all? Note that Chinese vendors often know little about what they are selling and product pages can be wrong. Typically there are visual clues on the back of the PCB, post a picture of your setup.

[Bodmer]

I was expecting a picture of the back of the TFT. I have seen quite a few reports where vendors send out screens with the wrong driver on them.

I doubt the banding is down to the library so I am unable to help further. It may be a different driver chip and certainly some chips do accept init sequences designed for other controllers and appear to work OK. The ILI9486 does not work well with a ILI9481 driver though, see example here.

Incidentally it is not a good idea to cut the GND line to a 5V powered function as the logic I/O lines then tend to adopt the rail voltage (5V in the case of the schematic design). The magnitude of the current flow into GPIO pins 16 and 17 of the ESP32 will depend on the design of that mystery box connected to them. Current limiting resistors (maybe 2K2) in those lines would be a good idea to limit the current if the magnitude is unknown. Perhaps that is the souce of the mysterous lines?

[lepromer]

@Bodmer

[lepromer]

@Bodmer

[Bodmer]

OK, yes it is one of those unmarked generic displays which can have ILI9486, ILI9481 and ILI9488 controllers. Sadly the controller has to be determined by experimentation if the supplier cannot be trusted.

[lepromer]

Thank you very much for your attention to my problem, I wish you success.

[Bodmer]

There are a number of ILI9481 init sequences that can be invoked, as detailed here. You could try each init sequence and see if there is one that works better. You must only enable 1 init sequence at a time.

[lbxhacker]

Very Thanks!I also encounter that problem,see your report,I try change init sequence to #define ILI9481_INIT_5,Now its Normal Work!

[lbxhacker]

Please change " TFT_eSPI-2.4.45\TFT_Drivers\ILI9481_Init.h" side at first word ,they have six init sequence,you can try
modify,good luck foy you!

[lepromer]

@lbxhacker I will try, thank You

[lepromer]

@lbxhacker @Bodmer thank You very much Ibxhacker, i used #define ILI9481_INIT_5, problem has gone, my tft screen work good. Thank You again @Bodmer and @lbxhacker