RS485 IMPLEMENTATION ON PIC MICO

Discussion in 'Programmer's Corner' started by RRITESH KAKKAR, Apr 14, 2015.

  1. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Hello,
    For serial communication can we use RS485 with multi drop features?
     
  2. Papabravo

    Expert

    Feb 24, 2006
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    You can do anything you want to do. The better question is do you understand how to use some kind of protocol to know when you should be talking and when you should be listening? A related question is: do you know how to put together a multidrop cable system?
     
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  3. OBW0549

    Well-Known Member

    Mar 2, 2015
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    Of course you can; that's what RS-485 is for.

    As for implementing RS-485 with a PIC, here's a hint: Googling "RS-485 with PIC" gives over half a million hits.
     
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  4. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Hello,
    I dont know how to this.!
     
  5. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
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    Hello,
    Is UART Tx and Rx serial communication is similar to this protocol?
     
  6. Papabravo

    Expert

    Feb 24, 2006
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    It will take more than a forum post.
    1. Put termination resistors only at the ends of the cable system. Never put them in a product.
    2. Limit the number of nodes on the cable system.
    3. Measure the transmit voltage levels on a transmitter at one end, and measure them again on the other end. How much degradation has there been?
    4. As you go to higher baudrates, beware of reflections
    5. Keep the droplines short
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    Yes, except that it can be half-duplex. What that means is that you cannot transmit and receive at the same time. You might also have to manage a TRANSMIT ENABLE signal on your transceiver. The framing and the asynchronous nature of the character transmission is just the same as RS-232.
     
  8. OBW0549

    Well-Known Member

    Mar 2, 2015
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