Unstable i2c device ID

Discussion in 'UDOO X86' started by Barış Saçıkara, Aug 20, 2019.

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  1. Barış Saçıkara

    Barış Saçıkara UDOOer

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    Hello,
    I'm trying to communicate a device with I2C port.(Not arduino i2c port.Udoo's native i2c port)
    I'm using a level shifter between device and i'm %100 sure level shifter is working because i already tried on Aduino Mega and it's works fine.But i think problem is about udoo's i2c port.
    My Problems :
    1)I'm listing i2c devices via
    Code:
    sudo i2cdetect -r -y 0
    
    and result is not stable.I mean my device sometimes shows on result and some times not.Here is the example picture.
    Screenshot from 2019-08-20 16-15-59.png

    I actually tried to connect 4.7k pull-up resistor but nothing changed.What can i do about this ?

    By the way i can successfully send commands and get result from device so i know cabling is correct.


    2)sometimes i2cdetect takes longer the refresh list its taking one second for per adress and sometimes it's refreshing list instantly.What could be reason for this issue ?

    Thanks.
     
  2. waltervl

    waltervl UDOOer

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  3. Barış Saçıkara

    Barış Saçıkara UDOOer

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    i dont have any problem with level shifter.but problem is my device is not stable on i2detect result.i actually tried on raspi and everything work great.I think there is some problem about udoo's i2c chip.
     
  4. waltervl

    waltervl UDOOer

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    If the level shifter is not working correct the I2C communication is not correct resulting in strange behavior.
    That you can use the levelshifter on a Mega does not mean it is compatible with the 1.8V - 3.3/5V without pull up you have to use for the Udoo X86 I2C.
    If you use the Arduino Part of the Udoo X86 I2C the level shifter you use can probably be used.
     
  5. Barış Saçıkara

    Barış Saçıkara UDOOer

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    Waltervl if i work from arduino i2c port everything works fine(which means 5v to 3.3 levelshifter working) and i dont have any problem with that but i tried level shifter on another 1.8v device and it's working good so i know levelshifter is working so what could be reason for this issue ? Do you have another idea ?
     
  6. waltervl

    waltervl UDOOer

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    I would advise you to drop your question with more technical details (i.e. what levelshifter) in the other I2C discussion thread so the people with I2C experience are getting notified and hopefully you get an answer.
     
  7. ccs_hello

    ccs_hello UDOOer

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