02F8-02FF ---- serial port, same as 0378 and 03F8


02F8   w   transmitter holding register
02F8   r   receiver buffer register
   r/w divisor latch, low byte   when DLAB=1
02F9   r/w divisor latch, high byte  when DLAB=1
   r/w interrupt enable register when DLAB=0
02FA   r   interrupt identification register
02FB   r/w line control register
02FC   r/w modem control register
02FD   r   line status register
02FF   r/w scratch register