Smart Home Automation Forum

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?

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.

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