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when i probe SCL then communication works else it doesnt..

jatin jain20
Prodigy 110 points
Other Parts Discussed in Thread: AM3352

Hi,

I am communicating with a device interfaced to TI sitara AM3352 over I2C. i was unable to communicate with the device so i probed SCL to analyze it on oscilloscope. When i probe it somehow communication works. When i remove the probe it stops communication stops working. i am using pull up resistor of 10K. Can anyone please help me regarding this behaviour..?

Thanks and Regards

Jatin

  • 0
    TI__Mastermind 24146 points

    Hello Jatin,

    What is the capacitive load on the bus?  Also, what data rate are you trying to run at?  10k pull ups sound week unless you are operating at lower frequencies.  You may want to reduce the size of the pull ups .  I am attaching a link to an app note that covers the design process of selecting the correct pull up resistor.

    http://www.ti.com/lit/an/slva689/slva689.pdf

    If you still have problems after revaluating the pull up value, let me know.

    -Francis Houde

  • 0 in reply to fhoude
    Prodigy 110 points

    Hello Francis,

    Thanks for you reply. I dont know about the capacitive load on the bus i need to check that and i tried with 100KHz and 400KHz in both cases result is the same. When i probe SCL communication works. i will look into into the link and then ill let you know if problem occurs again.

    Jatin Jain