FIFO Status

The UxFIFO register contains several Status bits for determining the state of the receive and transmit buffers.

The RXBE bit indicates that the receive FIFO is empty. This bit is essentially the inverse of UxRXIF. The RXBF bit indicates that the receive FIFO is full.

The TXBE bit indicates that the transmit buffer is empty (same as UxTXIF) and the TXBF bit indicates that the buffer is full. A third transmitter Status bit, TXWRE (transmit write error), is set whenever a UxTXB write is performed when the TXBF bit is set. This indicates that the write was unsuccessful.