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AM2432: Power off and power on with Uart connected, jump to backup boot mode

Zekun Bai
Expert 3545 points
Part Number: AM2432

Tool/software:

Hi

AM243 customer board

Senario：

Primary boot: ospi

Backup: uart boot

With uart connected to PC, Power off and power on, primary boot was jumped and go into backup boot.

Without uart connected to PC, power off and power on, ospi boot can succeed.

Reproduction way: 

Power off and power on in seconds, 100% reproduce into uart boot.

Power off, wait one minute or longer, power on, boot succeed

HW change:

With this, there is no problem:

With this, there is problem.


Customer need:

Help to analyze if there is HW issue, if yes, change to previous version, any risk left?

Thanks

Regards

Zekun

  • 0
    TI__Guru**** 190519 points

    Hello Zekun

    Thank you for the query.

    Customer needs to verify IO compatibility - if the 3.3V used for the logic is same as the IO supply for the IO group referenced by the UART 

    Is customer expecting the UART interface data to be available when the SOC supplies are off. The SOC IOs are not fail-safe and no inputs should be applied before the SOC supply ramps

    Regards,

    Sreenivasa

  • 0 in reply to Kallikuppa Sreenivasa
    TI__Guru**** 190519 points

    Hello Zekun

    Please refer below updated inputs.

    Kallikuppa Sreenivasa said:
    Customer needs to verify IO compatibility - if the 3.3V used for the logic is same as the IO supply for the IO group referenced by the UART 

    Customer needs to verify IO compatibility - if the 3.3V used for the logic IC is same as the IO supply for the IO group  (VDDSHVx) referenced by the SOC UART interface pins.

    Regards,

    Sreenivasa

  • 0 in reply to Kallikuppa Sreenivasa
    Prodigy 190 points

    Hi Sreenivasa:

       Zekun sending  the wrong message to you，we use the logic IC is no problem，this HW design there is problem,As shown in the figure below，but  power of CH430 of USB-TTL  supply by PC's USB interface.

    ，

  • 0 in reply to zhanglongc
    TI__Guru**** 190519 points

    Hello zhanglongc 

    Thank you for the inputs.

    SOC IOs are not fail-safe. No input should be applied before supply ramps.

    I assume the logic IC is powered by the IO supply that connects to the SOC.

    Regards,

    Sreenivasa

  • 0 in reply to Kallikuppa Sreenivasa
    Prodigy 190 points

    Hi Sreenivasa:

       1、So AM2432 jumped  go into backup boot (UART mode) when Power off and power on，Reasons for the USB-TTL  input to the AM2432 UART port before supply ramps?What's the harm in that?

     2、I'd also like to know why this problem is causing AM2432 jumped  go into backup boot (UART mode)。

  • 0 in reply to zhanglongc
    TI__Guru**** 190519 points

    Hello zhanglongc 

    Thank you.

    SOC IOs are not fail-safe. 

    If the inputs are applied to any of the SOC IOs before the supply ramps, this could cause voltage feed that could affect the power supply or SOC performance.

    I will need the complete schematics to be able to specifically answer the reason.

    Regards,

    Sreenivasa