Hi Abdul,
I'll wrap up the loose ends this week. What I am building uses the current code as a component of my bigger package. Today (a national holiday in England) I got the serial transmit interrupt system to work too, so I get a fixed length binary sequence of reply back from the little slaves when I command them, or send a nul command.

Have you used mode 3 ? I had a feeling you would be interested in the code !
Very best wishes./
Steve