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AM2434: Reserved Pin B8 of BOOT MODE pin

Hideaki Matsumoto
Genius 9805 points

Part Number: AM2434

Hi,

The customer has developed their own board with AM2434 (ALX), but the boot mode selection for DEV BOOT mode is not operated as they expected.

As the pin B8 of Boot Mode pin is reserved in the case of DEV BOOT mode, so either "1" (pull-up) or "0" (Low) is fine, correct ?

Reserved.jpg

However, the behavior was different in the case of High or Low on the pin B8 when they did SOC Initialization Using CCS Scripting.

In the case of Low at the pin B8, the script runs to “Happy Debugging”. Looks good.

However, in the case of "1" (High), nothing is displayed on the CIO terminal.

(Script stopped at “Running the board configuration initialization from R5!” on the Scripting Console.)

Script.jpg

 

Could you tell them why the behavior is different depending on the status of the pin B8 ?

 

They strongly want to fix the pin B8 as “High”, because this pin is used for lclk at QSPI boot.

Is it possible ?

Thanks and regards,

Hideaki

  • 0
    TI__Guru 63678 points

    Hi Hideaki,

    Hideaki Matsumoto said:
    Could you tell them why the behavior is different depending on the status of the pin B8 ?

    The Bootmode8 (B8) pin of the boot config represents the mode of operation(ARM/Thumb). When the pin B8 is set to High, it means the core is operating in Thumb mode, and if it is set to Low core is operating in ARM mode.

    Hideaki Matsumoto said:
    As the pin B8 of Boot Mode pin is reserved in the case of DEV BOOT mode, so either "1" (pull-up) or "0" (Low) is fine, correct ?

    The B8 pin needs to set Low for booting the device.

    Regards,

    Tushar

  • 0 in reply to Tushar Thakur
    TI__Genius 9805 points

    Hi Tushar,

    Thank you so much for your prompt response. That was really helpful. I've sent offline, but let me ask some questions here, too.

    • Could you tell us where the above description is written on ?
    • What happens in the Thumb mode ?

    Thanks and regards,

    Hideaki

  • +1 in reply to Hideaki Matsumoto
    TI__Guru 63678 points

    Hi Hideaki,

    From the internal mail chain, it looks like they are now able to boot the device keeping the B8 pin high.

    Please update with the changes what customer did to boot the device even when B8 is high?

    Regards,

    Tushar