Hi Shruti,

Before suggesting I want to know few things from u.

1. Does Master knows how many maximum slaves are there?
2. Is it possible for you to introduce hierarchy of slaves?
3. As you said earlier is it only the problem before knowing IDs at power on.
4. Is it possible to change logic of OE atleast for this part of power on.

If answers to all 4 questions are YES then you can try out following. (other wise also you can give it a try)

when master sends request for ID, (AAh, 01h, CCh), let the slaves start a timer.

A.> Slave1 (say id 49h) will respond immediately (AAh, 49h, CCh) by becoming a transmitter. while other slaves will remain in slave reciever mode.
When transmition is over for slave1 it will go back to reciever mode. & stop its timer.

B.> After say 10ms slave2 (say id 76h) will responds by becoming transmitter. When transmission is over it will go back to reciever mode & stop its timer.

C.> After another 10ms (20 ms after getting request from Master) slave 3 will do same thing. This will continue till all of them have finished sending ID.

D.> After receiving last ID master will go to transmitter mode.


In above method it 10ms is just indicative, you can change it according to your system.

Mahesh