Draw the format of SCON register.
SM0 SCON.7 Serial port mode specifier
SM1 SCON.6 Serial port mode specifier
SM2 SCON.5 Used for multiprocessor communication (Make it 0.)
REN SCON.4 Set/ cleared by software to enable/ disable reception.
TB8 SCON.3 Not widely used.
RB8 SCON.2 Not widely used
TI SCON.1 Transmit interrupt flag. Set by hardware at the beginning of the stop Bit in mode 1. Must be cleared by software.
RI SCON.0 Receive interrupt flag. Set by hardware halfway through the stop bit time in mode 1. Must be cleared by software.