Serial communcation

Discussion in 'Embedded Systems and Microcontrollers' started by illayaraja, Nov 13, 2015.

  1. illayaraja

    Thread Starter New Member

    Oct 6, 2015
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    Hello fnds .......hellp me .................
    I need to interface 5 to 8 serial port device, In our micro controller ...... like serial load cell, GPS, serial sensor ,serial printer,ect.....
    which one is the perfect micro-controller for this project and I used arduino UNOR3 but it can handle only 3 device ........Another think device are different baud rate .....each device have separate baud rate ......like 2400,9600,11200......
     
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Sounds expansive.
    I would probably use several small uC.
     
  3. John P

    AAC Fanatic!

    Oct 14, 2008
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    Same here. Maybe get the cheapest controllers around which have UART and SPI, and make each one communicate with its sensor/GPS/printer and talk to a master processor via SPI.
     
  4. illayaraja

    Thread Starter New Member

    Oct 6, 2015
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    Thank you ...........
    but need single output ......TX.....i want receive multi input data form the devices and i would transmit through wifi......
     
  5. illayaraja

    Thread Starter New Member

    Oct 6, 2015
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    OKay ....i don't have idea about SPI .....plz send any links,circuit or tutorial ......thanks @ john
     
  6. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
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    See: http://www.nxp.com/documents/data_sheet/SC16IS752_SC16IS762.pdf

    I2Cand SPI are two serial interfaces. The Arduino should support both. There is an I2C document on NXP's site, since they invented the protocal.

    I2C uses devices with addresses that are assigned by NXP. Some devices allow multiple address assignments by strapping pins. You can also have multiple busses. It's two wires and ground. There are multiple speeds for the bus,

    SPI is serial as well, but the device is selected more like the Chip Select signals on memory.
     
  7. shteii01

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    Feb 19, 2010
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    KISS mentioned I2C. That is actually doable. I don't like SPI because you need separate pin to select each device. I am sort of looking at it from Arduino implementation...
    1) Get 10 nano boards (or whatever little boards Arduino is selling and everyone is copying).
    2) Connect the serial devices to serial ports on the nano boards.
    3) Use some Arduino board (uno, nano, "whatever") as a master, connect the nano boards to the master using I2C. Since the nano boards will be near master, the I2C distance limit is not likely to matter. I have worked with I2C 4x20 lcd unit that had like a foot of wire and we sent text to it from Arduino Due just fine.

    A more interesting question is the serial hardware on the devices. Are they using RS-232? If they do then the OP will need level translators to convert RS-232 into 5 volts that the Arduino boards are using for the serial coms.
     
  8. KeepItSimpleStupid

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    Mar 4, 2014
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  9. John P

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    Oct 14, 2008
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    That's exactly why I do like it. One enable line per processor is very simple to deal with, and easy to check with a scope. Of course, if the master processor has all its pins tied up with other hardware, then you have to consider alternatives, but if all it's doing is coordinating several peripherals and sending the data out to a computer, you may not need many pins for other purposes. As always, "it depends".
     
  10. illayaraja

    Thread Starter New Member

    Oct 6, 2015
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    thanks ..... fnds...... now i got some about communication.....any other easy ...?
     
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