I got my UART working just in basic sending and receiving. Now I am trying to implement buffer feature and other non-blocking features. I have done this on other CPU's many times. But I noticed there is an app_uart driver. But by looking into app_uart.c, I couldn't find anywhere the driver is handling the buffer. It looks like the user needs to implement every buffer related features in an app_uart_event_handler_t event.
Also notice that app_uart_flush is not doing anything in the code.
Did I miss anything? APP_UART_FIFO_INIT looks very promising, but where is the implementation?
I just didn't want reinvent the wheels if there is a nice UART drivers has been developed by Nordic.