Even though the programmer’s model has only one Serial Port Buffer (SBUFx), there are essentially two separate and distinct hardware buffers (registers) - the transmit write-only buffer and the receive read-only register. Writing to SBUF0 sends the data out serially from the Transmit Shift register through the TX0 pin. The data received on the RX0 pin is accumulated in the Receive Latch. A read of SBUF0 fetches the data from the Receive Latch. The Serial Port Control register (SCONx) contains the status and control bits. The control bits set the operating mode for the serial port, and status bits indicate the end of the character transmission or reception. The status bits are tested in software (polling) or programmed to cause an interrupt.