Software starts a manual transfer by writing a 1 to the spi.Config [Man_start_com] bit. When the software writes the 1, the controller hardware starts the data transfer and transfers all the data bytes present in the TXFIFO. The [Man_start_com] bit is self-clearing. Writing a 1 to this bit is ignored if [Man_start_en] = 0. Writing a 0 to [Man_start_com] has no effect, regardless of mode.