KC868-A4 with Nextion 5 inch display issue

[VovaN_60]

Hello all.

System:
KC868-A4 board with Nextion NX8048P050-011C-Y display.

Problem:
UART communication with this particular display. Other 2.4 inch Nextion works well.
Possibly issue with TTL level.

Electrical connection info:
RS323 chip (SP3232EEN) removed from the KC868-A4 board.
The RX and TX of Nextion are connected directly to GPIO_16 and GPIO_17 of ESP32.
We have tried to use other GPIO's of ESP32. Nothing works.

The solution which works:
Replacing ESP32-S with original ESP32-WROOVER.

Question:
1) Can anyone suggest a simplier solution?
2) Is there any way to force Nextion to operate on 3.3v TTL level?
3) Can we connect Nextion to RS232 connector directly without removing SP3232EEN?

[admin]

Nextion can work for 3.3v or 5v TTL level. can you confirm with your Nextion model what serial port level use?
if you have test with ESP32-WROOM is no problem, i think the fast way is replace the ESP32 module. Now we sell KC868-A4 board all are use by ESP32-WROOM model, not use ESP32-S. so if I test with your Nextion NX8048P050-011C-Y display, i think it also will be work fine.
about your questions-3, if you connect Nextion without SP3232EEN, you just connect to ESP32's TXD,RXD pin directly. SP3232EEN just for serial level convert, that for 3.3v->12v RS232 level.

[YOO SEOK]

Do you have sample code for kc868 and NEXTION HMI communication connection?