BigDogIn order to select 9-bit transmission, the TX9 bit (TXSTA<6>) should be set and the ninth bit
should be written to the TX9D bit (TXSTA<0>). The ninth bit must be written before writing the
8-bit data to the TXREG register. This is because a data write to the TXREG can result in an
immediate transfer of the data to the TSR register (if the TSR is empty). If the TSR was empty
and the TXREG was written before writing the “new” value to the TX9D bit, the “present” value of
of the TX9D bit is loaded.
movlw 0x00 movwf trisc or movlw 0xff movwf trisc