47.5.7 SDO Disable
The DISSDO bit determines if the SPI uses the SDO pin. Changing the value of DISSDO, immediately changes the control of the SDO pin between the SPI and Port function. The DISSDO bit is applicable to all SPI operating modes.
If DISSDO = 0, the SPI pops data from the SPIxTXB into the register and transmits data through the SDO pin. If DISSDI = 1, the SPI does not pop data from the SPIxTXB and does not use the SDO pin.
DISSDO can be modified while transmitting data. However, doing so usually corrupts the data in that word as the Port logic supplies the values for the remaining bits.