i first of all thans Neil to make my figure clear and understandable to anyone.

 I will go through the "external mempory interface on p1 of Chapter 1, and p6 of Chapter 3." and then see.

I will also gothrough interrupts described on p18 of Chapter 3. 

1)   Which microcontroller?  - DALLAS DS89C430----This micro has
      only /R and /W lines. No /IOR or /IOW is present.

2)   Look at the signals that are on your microcontroller, 
     and work out how to use them to activate the UART's /IOR 
     and /IOW lines.???????????? 
     It should be possible using SIMPLE LOGIC GATES??????
    
      HOW to do that i can get. What signls to use along with
      /R and /W to convert them into /IOR and /IOW.