ok lets declare the system : all uc Are 80c51 Atmel
uc1: sensors are connected to it (heat, ir, smoke, pressure) which leads to 6 actions . which usually send to the main controller to take action and make the other uc make a call
uc2: the main microcontroller which is connected to a keybad and lcd and also should get actions from uc1 and send to uc3 to make a call or whatever.
uc3:the dtmf uc which make calls or receive calls and also deals with the main controller from the case of setting system on , off or armed (some states)
So there is data transefer between the 3 uc
from uc1 to uc2 it is 8 bits,
from uc3 to uc2 it is 8 bits,
and reverse is da same uc2 to uc1 or uc3 is 8 bits.
Also each one would be running on different speed. so they are asynchronous.
hope that code help alil.
the problem is the transfer time not how to transfer, coz all what i m afraid from is if the uc1( sensor microcontroller ) got an alarm from the ir so it gets out the action of it. suppose it 10110010 and then it finds over heat so it will gets out 10011000. So i m afraid of override of data. as it would not be synchronous with uc1.
is what i think is wright?!
thanks for ur care and help guys