SPI or I2C better for 2 lcd displaying same data?

Discussion in 'Digital Circuit Design' started by GoExtreme, May 30, 2018.

  1. GoExtreme

    Thread Starter Member

    Mar 4, 2018
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    Im working on a voltmeter that will requires LCD's in different spots. 2 or 3 LCD's will display the same data.
    My current design has i2c oled on different addresses but wondering if SPI with clock select to few screens at once will work?
     
  2. joeyd999

    AAC Fanatic!

    Jun 6, 2011
    4,200
    6,282

    It'll work for writing data only. You will not be able to read back data or status. There will be SDO contention.
     
  3. Ian Rogers

    Well-Known Member

    Dec 12, 2012
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    I2C normally has 8 addresses.... How far will the display be from the controller? I2C doesn't travel far! You may be better off with 485..

    I have done CS on two screens, One had a not gate so when one was active the other wasn't and visa versa... ( well a transistor as a not )..
     
  4. GoExtreme

    Thread Starter Member

    Mar 4, 2018
    52
    3
    Screen are on about 5-6 inch harness.
     
  5. Ian Rogers

    Well-Known Member

    Dec 12, 2012
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    Can you afford to have several CS pins? I2C and SPI will work at those lengths.. Personally I would use the I2C..
     
  6. GoExtreme

    Thread Starter Member

    Mar 4, 2018
    52
    3
    I have room for multiple CS. However I think I2C is fast enough for what I need. I was just thinking with SPI maybe I could refresh screens at the same time by having 2 or 3 CS selected at the same time.
     
  7. dendad

    Distinguished Member

    Feb 20, 2016
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    If you have both screens at the same I2C address, and you are only writing to them, just treat them as a single display and both should show the same info.
     
  8. GoExtreme

    Thread Starter Member

    Mar 4, 2018
    52
    3
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