When operating in Half-Duplex mode, where the microcontroller needs to reverse the
transceiver direction after a reception, it may be more convenient to hold off the
UxRXIF interrupt until the end of the Stop bits to avoid line contention. The user
selects when the UxRXIF interrupt occurs with the
STPMD bit. When STPMD is ‘
1’, the
UxRXIF interrupt occurs at the end of the last Stop bit. When STPMD is ‘
0’, the UxRXIF interrupt occurs when the received byte is
stored in the receive FIFO. When
STP =
10, the store operation is
performed in the middle of the second Stop bit, otherwise, it is performed in the middle
of the first Stop bit.
The FERIF and PERIF interrupts are not delayed with STPMD. When STPMD is
set, the preferred indicator for reversing transceiver direction is the UxRXIF interrupt
because it is delayed whereas the others are not.