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AM62A7-Q1: Handling of floating pins

liu xiwen
Prodigy 200 points

Part Number: AM62A7-Q1
Other Parts Discussed in Thread: AM62A7

Hi,teams

The AM62A manual provides instructions on the unused configurations for some of the pins.But not all pins were covered.

May I ask if the other unused pins of AM62A7, such as RGMII, eMMC and GPIO, require external hardware pull-up/pull-down configuration? Or should they be configured in the initial state through software? Or can I leave the unused pins unconnected?

image.png

Thank you for your help.

Xiwen

  • 0
    TI__Guru**** 232565 points

    Hello Xiwen

    Thank you for the query.

    Please read the notes at the start and end of the below section

    5.4 Pin Connectivity Requirements

    FYI, notes at the end

    Regards,

    Sreenivasa

  • 0
    TI__Guru 64835 points

    It is not possible for the table you referenced to address all possible combinations of connectivity options. The connection recommendations included in the table are meant to address the most likely pins that need special consideration. For example, the boot mode inputs must be tied-off to indicate your specific system boot sequence.

    There is a note following the table that explains how many of the configurable device IOs are turned off by default. Any IO with its input buffer (RX) turned off is allowed to float without damaging the device. However, any IO with its input buffer (RX) turned on shall never be allowed to float to any potential between VILSS and VIHSS. The input buffer can enter a high-current state if allowed to float, and this condition could damage the IO cell. You must ensure your application software never enables any of the AM62Ax inputs buffers when the attached signal is not pulled or driven to a valid logic state.

    The comment above does not address requirements of devices you attach to AM62Ax. It may be necessary to include an external pull on any signal connecting AM62Ax to the input of an attached device. The external pull may be needed to hold the input of the attached device in a valid logic state until the AM62Ax application software has booted and configures the selected peripheral and IO such that the signal is driven.

    The system designer is expected to understand how the AM62Ax and attached device functions, so they can design their system to provide the appropriate connectivity and configure their application software to accommodate the connectivity requirements for all operating conditions beginning with initial power-on, going through the boot sequencies, during normal operation, and ending with power-off.

    Regards,
    Paul

  • 0 in reply to peaves
    Prodigy 200 points

    Hi，Paul，Sreenivasa

    Thank you both for your help. I checked the pins and found that there are no RX descriptions or unused handling descriptions for A8 and A9 (WKUP_LFOSC0). Could you please take a look at these two pins? If they are not in use, how should I handle them?

    Thanks,

    xiwen

  • +1 in reply to liu xiwen
    TI__Guru**** 232565 points

    Hello Xiwen

    Thank you.

    These are clock pins.

    WKUP_LFOSC0 has specific connection requirements when not used

    Please review below section of the processor data sheet

    6.12.4.1.5 WKUP_LFOSC0 Not Used

    Regards,

    Sreenivasa