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Original question:

LAUNCHXL-F28377S: SCI boot flash programming with C2prog

TMS320F28377S: Using SCI boot mode

Ankit Srivastava
Expert 1160 points
Part Number: TMS320F28377S
Other Parts Discussed in Thread: C2000WARE

Hi,

I have a confusion regarding SCI boot mode. I want to use default configurations i.e. I don't want to change anything on OTP.

In that scenario, if an external controller pulls GPIO72 low and GPIO84 high, SCI boot mode should be selected. Now the default pins for SCI boot mode are GPIO84 for TX and GPIO85 for RX. Will there be a conflict between boot mode pins and SCI pins? 

Thanks and Regards,

Ankit

  • 0
    TI__Mastermind 30255 points
    Ankit

    You should be able to avoid conflict by first using them as boot mode select pins then after a certain amount of time (for example 500us), switch to using them as SCI. Once the boot mode is determined, boot no longer requires use of the pins and they get muxed for SCI.

    Best regards
    Chris
  • 0 in reply to Christopher Chiarella
    Expert 1160 points

    Hi Christopher,

    Thanks for your reply. I would also like to clarify more on this.
    Inside my main application, I want to use GPIO84 and GPIO85 as normal SCIA pins to transfer data to an external microcontroller. However after a reset, that external microcontroller (when try to flash new application) will set the GPIO72 to low and GPIO84 to high and transfer the new application through GPIO84 and GPIO85 as bootmode SCIA pins to the flash. After transferring the data to flash, it will jump to the entry point of the new application and inside the new application I can use the GPIO84 and GPIO85 as normal SCIA pins again for the data transfer to the external microcontroller.
    May I know whether my understanding is correct or there is any conflict? 

    Also GPIO84 while selecting the mode is input pin but while using as SCITX is output pin. So, this switching is handled internally by the chip?


    Thanks and Regards,
    Ankit

  • 0 in reply to Ankit Srivastava
    TI__Mastermind 30255 points
    Ankit

    SCI bootloader will load data to RAM, not flash. Otherwise, what you described should be doable.
    Upon reset, GPIOs default to input and then when you configure the GPIO MUX to use the GPIOs for SCI, it will switch their direction accordingly.
    In general, there is SCI examples in C2000Ware you can reference.

    Best regards
    Chris
  • 0 in reply to Christopher Chiarella
    Expert 1160 points
    Dear Chris,

    Thanks a lot for your reply.

    Regards,
    Ankit