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AM2432: Pin Assignment

Mari Tsunoda
Expert 5726 points
Part Number: AM2432


Hi Team,

I received two questions from my customer regarding pin assignment as follows.

  1.  According to 6.4 Pin Connectivity Requirements on AM243x datasheet, I2C0_SCL, I2C0_SDA, MCU_I2C0_SCL, MCU_U2C0_SDA pins need to be pulled-up externally. Are external pull-ups necessary even if we don't use these pins for I2C function? We use the B18pin(I2C0_SDA) for GPIO0_65, and other pins are not used. So  we want them to be Un-connected.
  2. Why are internal pull-ups not available on I2C0_SCL, I2C0_SDA, MCU_I2C0_SCL, MCU_U2C0_SDA?
    According to 6.4 Pin Connectivity Requirements on AM243x datasheet, "Each of these balls must be connected to the corresponding power supply(1) through separate external pull resistors to ensure these balls are held to a valid logic high level."

Any insight is very much appreciated.

Best regards,

Mari Tsunoda

  • 0
    TI__Mastermind 24743 points

    Hey Mari,

    1) Yes, the external pull-ups are necessary even if being used for GPIO signal and not I2C. Even if the other 3 pins are unused, they should be pulled high, if balls are allowed to float between valid logic levels, the input buffer may enter a high-current state which could damage the IO cell.

    2) These pins use the I2C Open Drain IO Voltage buffer instead of the common LVCMOS buffer. This is true regardless of the chosen muxmode option and associated signal, hence the requirement for external pull up resistors. We should also point out that this I2C OD buffer is much slower than the LVCMOS buffer used for other GPIO pins and discrepancy should be taken into account.

    Best Regards,

    Zackary Fleenor