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AM2434: Regardless of 3.3V mode or 1.8V mode, it should be 200k is normal for I2C.?

Shaoxing Ke
Expert 3590 points

Part Number: AM2434
Other Parts Discussed in Thread: LP-AM243

Hi Experts,

I am asking for my customer here.

Using FPGA as I2C Master, Using LP-AM243 as I2C Slave, and the clock rate is 200K, the slave machine is easy to drop.

But we found that the I2C spec from TRM, regardless of 3.3V mode or 1.8V mode, it should be 200k is normal. Any suggestion/Dir here? Thanks.

  • 0
    TI__Guru 57015 points

    Hi Shaoxing,

    Both the CLK and DATA line of I2C have to be pulled up. Did they configure the pull up for I2C lines in syscfg for AM243x LP as slave?

    Best regards,

    Ming

  • 0 in reply to Ming Wei
    TI__Expert 3590 points

    Hi Ming,

    Checked before, the CLK and DATA line of I2C pulled up. Do Bu Team test the I2C communication rate? And any other suggestion?

    I have asked the customer to provide the configured I2C code and setup environment, and will let you know once there is an update. Thanks.

  • 0 in reply to Shaoxing Ke
    TI__Guru 57015 points

    Hi Shaoxing,

    We do not have any other suggestions at this point!

    Best regards,

    Ming

  • 0 in reply to Ming Wei
    TI__Guru 57015 points

    Hi Shaoxing,

    I will forward this thread to our HW apps for further help!

    Best regards,

    Ming

  • 0 in reply to Ming Wei
    TI__Mastermind 23005 points

    Hi Shaoxing,

    Have you viewed the waveforms on an oscilloscope to verify the waveforms look correct?

    Also, which version of the LP-AM243 board to you have? E3, E3A, E3B, something else?  There should be silkscreen text or a sticker right in the middle of the board that says something like "PROC109E3A".  This is located right underneath the TI logo. 

    Also, which I2C interface on the LaunchPad are you using?

    Some older LP-AM243 boards had a low pass filter on the I2C lines (cutoff frequency was 25MHz, so doesn't impact 400kbps I2C) that created too large of a voltage divider on the line and a "low" was not always read as a '0' by the I2C controller.  This should be fixed on revision E3B.

    Thanks,
    Mike