Half-Duplex Mode: When this bit is 1, the transmitter operates in
half-duplex mode. When this bit is 0, the transmitter operates in
full-duplex mode. Only full-duplex is supported so this bit should
always be set to 0.
Fast Simplex Link (FSL) Interface Description
The Fast Simplex Link bus provides a point-to-point communication channel between an output FIFO and an input FIFO.