I need resourceful information's on how to implement the serial protocol via an RS485 interface. As regards to my area of application, I simple want to communicate with my micro-controller via an RS485 port. How do I go about this? Any useful links with useful steps will be appreciated.


I am designing an energy meter with interfaces in-other for it to communicate with the outside world, to READ and WRITE informations. I intend to add to it the RS485 interface just like the Optical communication interface which I have already implemented. I want to know if there is anyway I can combine the serial protocol communicating via the RS485 interface. I hope this is more clearer.


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    \$\begingroup\$ this is pretty broad, and will probably attract negative attention as written - you may want to edit your question before that happens. \$\endgroup\$ – JustJeff Jan 14 '12 at 14:08
  • \$\begingroup\$ i.e., what microcontroller? rs485 ports aren't common on PC hardware, so what have you got that has a 485 port? Or do you actually mean 232? You need to supply details in order to get answers. \$\endgroup\$ – JustJeff Jan 14 '12 at 14:10
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    \$\begingroup\$ There's a mild language barrier here. "THE serial protocol" is not meaningful, as there are probably tens of thousands of serial protocols in the world. I assume you have an existing protocol that you are using over an optical link, that you would like to use over RS485? RS485 probably has a much smaller bandwidth than optical, and it also is only half duplex. It is also a good idea to have a delay of at least 1-5ms between any transmitting and receiving to allow transmitters to power up and down. Can you force your optical protocol to work with those constraints? \$\endgroup\$ – darron Jan 15 '12 at 19:57

I want to know if there is anyway I can combine the serial protocol communicating via the RS485 interface

RS485 doesn't have any defined serial protocol -- it's just the physical layer for specifying a multidrop differential signaling network, + a UART data link layer for encoding bytes via start/stop bits like RS232.


Covert the sensor output by using controller to UART (Rx/Tx) standard. Feed the same UART signal into the input of RS485 electrical level converter and inject into your transmission medium. i.e, transmission medium will carry UART-RS485 differential signal.


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