Can I program and boot from FLASH after OTP?

Now I'm trying some examples running from RAM and from FLASH. I would try with OTP. Is it possible to run code from RAM or  FLASH after trying with OTP? If Yes, what should I change (if any) for programming example in OTP and than back to progamming FLASH?

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  • Hi JackDialog,

    As OTP memory is one time programmable you should take extra care when trying to burn or boot from it. Please refer to the bootROM sequence section of the datasheet, page 65-

    https://www.renesas.com/eu/en/document/dst/da14531-datasheet?language=en&r=1564826 

    Note the diagram in page 66. The booter checks the application flags in the OTP and decides whether the device is in development or normal mode. In normal mode the device will boot up from OTP code (mirroring the OTP contents to SRAM). In development mode the booter will cycle through peripherals providing the option to boot from e.g. an SPI flash or loading code to the RAM using the UART or SWD.

    After burning the OTP applcation flags you will only be able to re-program the device via SWD (as long as you haven't disabled the SWD in the corresponding field in the Configuration script - see page 64 of the datasheet or disabled the debugger in your firmware).

    Considering the above it is strongly recommended to perform all your code testing using other boot options (as also mentioned by louis13) and only in the final development stages test the OTP burning and booting. Please also refer to the document below for more information on booting from OTP or external devices

    https://www.renesas.com/eu/en/document/apn/b-072-da14531-booting-otp-and-serial-interfaces?language=en&r=1564826 

    Best regards,
    AA_Dialog

Reply
  • Hi JackDialog,

    As OTP memory is one time programmable you should take extra care when trying to burn or boot from it. Please refer to the bootROM sequence section of the datasheet, page 65-

    https://www.renesas.com/eu/en/document/dst/da14531-datasheet?language=en&r=1564826 

    Note the diagram in page 66. The booter checks the application flags in the OTP and decides whether the device is in development or normal mode. In normal mode the device will boot up from OTP code (mirroring the OTP contents to SRAM). In development mode the booter will cycle through peripherals providing the option to boot from e.g. an SPI flash or loading code to the RAM using the UART or SWD.

    After burning the OTP applcation flags you will only be able to re-program the device via SWD (as long as you haven't disabled the SWD in the corresponding field in the Configuration script - see page 64 of the datasheet or disabled the debugger in your firmware).

    Considering the above it is strongly recommended to perform all your code testing using other boot options (as also mentioned by louis13) and only in the final development stages test the OTP burning and booting. Please also refer to the document below for more information on booting from OTP or external devices

    https://www.renesas.com/eu/en/document/apn/b-072-da14531-booting-otp-and-serial-interfaces?language=en&r=1564826 

    Best regards,
    AA_Dialog

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