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TMS320F28379D: the boot mode pin is conflicted with SCI Boot gpio?

Part Number: TMS320F28379D

Customer is using F28379D control card, and wants to use SCI boot mode by switching the default boot mode pins GPIO72 and GPIO84. However, the  default GPIO for SCI Boot is GPIO84 and GPIO85 for SCITXDA and SCIRXDA, respectively. Is there any issue for GPIO84? I am not sure whether the GPIO84=1 is  weak pullup or not, if so, it can be configured to work as SCITXDA  after boot process? 

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  • Hi,

    I am not sure what you are asking about an issue with 84?

    At boot up the GPIO is configured as a GPIO IN pin and is read to determine the boot mode selection.

    If SCI bootloader is selected, then the GPIO is configured as a SCI pin and then the bootloader code is executed.

    There should be no issue.

    sal

  • Hi sal,

    I think the main concern is that GPIO84 is used for boot mode pin, and it is always pulled up to VDD_3V3 through 56k ohm resistor for SCI boot mode. So based on your comment, GPIO84 can also be driven as SCI pin for bootloader communication after configured with GPIO mux selection , right?  Or we don't need to configure GPIO mux selection for GPIO84?

  • You don't need to.

    The Boot ROM code will configure it once the SCI boot mode is selected after reading the boot mode select pins after reset.

    Please see the Technical Reference Manual for more details.

    sal