there are 2 multiprocessor modes
Mode 2 and mode 3.
Mode 2: smod=0 =>baud rate = f/32
smod=1 => b.r=f/64
mode 3: variable baud rate.
TH1=[256-(K*f)/(384*b.r)]
K=1 when SMOD=0
K=2 when SMOD=1
example if f=11.0592Mhz,
TH1=0FDh,
K=2, then

b.r=19200

SM0 SM1
1 0 ......mode 2
1 1 ......mode 3