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why we use ports ?

Discussion in 'Microcontrollers, Programming and IoT' started by Jibin, Jul 23, 2015.

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  1. Jibin

    Jibin

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    Jul 20, 2015
    In microcontrollers, we says that we connect devices to and from microcontroller's input/output port pins(for eg: take 8051 mc, it has 4 I/O ports)..my doubt is that why we need the use of ports?...can we connect the wires of devices directly to microcontrollers pins..
     
  2. BobK

    BobK

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    You apparently misunderstand what ports are. They are pins that you can either control or read from the microcontroller. Of course you connect external signals to a microprocessor pin. That pin is either an input or an output pin to the microcontroller. What else would you connect it to, a power pin?

    Bob
     
  3. Jibin

    Jibin

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    Jul 20, 2015
    Okey with that..
    But can you tell me why we use ports for connecting devices (generally in computers)
     
  4. davenn

    davenn Moderator

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    read AGAIN what Bob wrote
    The word port is just the term for the in/out connection to the processor chip or other controller/memory chip
     
  5. Minder

    Minder

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    In computers there are also physical connection ports to the outside world COM port,Parallel Port, USB port etc.
    These are not to be confused with the ones already stated, physical pins on the processor.
    M.
     
  6. Martaine2005

    Martaine2005

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    Just to add to all of the above:
    GENERALLY, it is because of the amount of wires that need connecting.
    Why would you want to connect 13 pins individually, when you can just plug in 'port' a connector?

    Also 'ports' are used to identify a protocol to certain devices or url's.

    Martin
     
  7. Gryd3

    Gryd3

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    Let's try to clear it all up at the same time.

    When talking about 'physical' items like microcontrollers, computers, cars, etc...
    A 'PORT' is a collection of pins.
    -This collection of pins is a logical group. ie, pins 14-19 belong to 'Port B'.
    -Or can be a physical group. is, the collection of pins in a DB9 connector is the 'Serial' port.

    Using Ports to deal with a set of pins is much easier than connecting to each pin by itself, or controlling each pin by itself. It's like handing someone paperwork for a job you need to do, but giving them all loose papers... Staple it together and call it a 'package' .. same kind of thing.


    There is a confusing use for 'PORT' for computers though... and this refers to networking.
    I will not go into extensive details, but every networked device has an address. On the internet, in order to communicate, computers need an 'ip address' and 'port' number to communicate over. In this situation, a port number can be compared to a 'channel' like in a radio. If you send the information on the wrong channel, it won't reach it's destination even if it's address is correct.
     
    chopnhack and CDRIVE like this.
  8. BobK

    BobK

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    Why do we use ports to transport goods from China to the US? Shanghai - output port, San Francisco - input port. Of course both are actually bidirectional ports.

    Bob
     
  9. Colin Mitchell

    Colin Mitchell

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    I also have a little port every night.
     
  10. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    This was an EXCELLENT explanation. ;)
    This is funny but a good analogy too! :)

    This?? Well this is just funny. :p

    Chris
     
    Gryd3 likes this.
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