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I need help to creat a code(.asm) for communication between multiple microcontrollers using RS485.So,pls help me with some sampule code (Using At89s51/52)
In a RS485 bus, definition of master/slave role is a pure software matter.Only 1 master per RS485 bus, hardwired and impossible to change after network setup.
Not only theoretically possible but widely used in industrial communication. RS485 is only the physical layer (OSI layer 1) and not fixing master/slave role. In a multi-master RS485 bus, there must be a layer 2 protocol that dynamically assigns the master role to different nodes. PROFIBUS is e.g. using a token passing scheme to assure that only one master is trying to control the bus at a time.Multi master RS485 are theoretically possible, but very hard to implement and is much cheaper to go for another multi master bus.
RS485 is half duplex so u can send data or recive data at a time.
and both can be posible by increase wire counts.
PROFIBUS is e.g. using a token passing scheme to assure that only one master is trying to control the bus at a time.
Multi wire RS485 is not RS485 !
Is RS422 !
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Can we have an implementation ?
I have tried to do that but it is way cheaper to go to another bus.