Hi:
I use sdk:nRF5_SDK_17.0.2_d674dde and NRF52840.
Reference examples:nRF5_SDK_17.0.2_d674dde\examples\peripheral\uart
PC connection RX-pin20 and TX-pin22, PC sends data, it does not enter static void uart_event_handle(app_uart_evt_t * p_event).
PC TX---NRF52840 RX
PC RX---NRF52840 TX
Attachment is the source code: