Serial Communication Modes 2 and 3 allow one
" 8051 to control several “
The serial port can be programmed to generate an
interrupt (RI) if the 9th data bit = 1 by setting the
bit in SCON.
The TXD outputs of the slaves are tied together and to
the RXD input of the master. The RXD inputs of the
slaves are tied together and to the TXD output of the
Each slave is assigned an address. Address bytes
transmitted by the master have the 9th bit = 1 & data
bytes have it = 0.