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AM6421: Issue with Unexpected ADP Bit Setting in W25Q256 during XSPI Boot on AM64x

Ryan LIU
Prodigy 180 points
Part Number: AM6421

Tool/software:

Hello,

We are encountering an issue related to external flash booting while performing high-frequency power cycling tests on the TI AM64x processor.

The system is configured to boot from an external W25Q256 flash device using the XSPI boot mode. During testing, we occasionally observe SBL (Secondary Bootloader) execution hangs. After power cycling, the RBL (ROM Bootloader) fails to successfully load the SBL.

Upon investigation, we found that the ADP bit (Addressing Mode Bit) in Status Register 3 of the W25Q256 has been unexpectedly set, forcing the flash into 4-byte address mode. This is problematic because neither our SBL nor application code includes any operation that intentionally modifies this bit, indicating an unintended state change.

Notably, this issue does not occur when using QSPI or standard SPI boot modes—system booting remains stable in those configurations.

Could there be any known risk in XSPI mode that might lead to unintended writes to the flash status register?

Thank you for your support!

Best regards

Ryan

  • 0
    TI__Mastermind 44476 points

    Hi Ryan,

    Ryan LIU said:
    Could there be any known risk in XSPI mode that might lead to unintended writes to the flash status register?

    When ROM boots in xSPI bootmode, it does not performs any write operation, all it does is read, so from ROM boot perspective the bit you are talking about cannot be written to.

    Now coming to the bootmode which you are using, please let me know the bootmode pin configuration which you have.

    I need to get the values of the following bootmode pins:

    Moreover, share the flash datasheet as well.

    Looking forward to your response.

    Thanks,

    Vaibhav