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TMS320F28P659DK-Q1: How to lock the boot mode configuration ?

Davide Dentoni
Prodigy 175 points
Part Number: TMS320F28P659DK-Q1
Other Parts Discussed in Thread: UNIFLASH, C2000WARE

Hello support,

let's assume that I configure the boot mode as "Zero Boot Mode Select Pins" as explained in the TRM par. 4.4.3.1

How can I be sure that this configuration cannot be modified (for instance through Uniflash) overwriting 

Set BOOTPIN_CONFIG.BMSP0 to 0xFF
Set BOOTPIN_CONFIG.BMSP1 to 0xFF
Set BOOTPIN_CONFIG.BMSP2 to 0xFF
Set BOOTPIN_CONFIG.KEY to 0x5A

and then writing a 0x01 over a 0x03 (Flash) into register BOOTDEF.BOOTDEF0, changing the boot mode from Flash to SCI/Wait ?

Is there a way to lock the boot mode configuration ?

  • 0
    TI__Genius 11525 points

    Hi Davide,

    That is the way to change the boot mode default from Flash to SCI Boot Mode (uses GPIO12 and GPIO13 as default). The boot mode can easier be changed through emulation-boot mode.

    In order to lock the boot mode configuration, you must program the OTP of the device, however, I should state as a warning this is a permanent option.

    Is the intention of this change to not use the boot pins for any other mode than SCI ("zero boot mode")?

    Thanks,

    Charles

  • 0 in reply to Charles Roberson
    Prodigy 175 points

    Hello,

    intention is to prevent the possibility that some hacker can force the DSP to a different boot mode. It is a request coming from the safety dept. about cybersecurity.

    In our project we have a custom bootloader resident in Flash, therefore our only need is the boot from Flash.

    We are using Flash entry point 0x80000

    Until today we have not configured any register, therefore I think we are in the case of "Default Boot mode" explained at par. 4.3.1, with GPIO72 and GPIO84 to 1 at wakeup --> Boot from Flash/USB

     Do you think programming the OTP in the proper way (BOOTDEF) is a solution to prevent hacking of boot mode ?

    Or maybe it could be enough the activation of JTAGLOCK ?

  • 0 in reply to Davide Dentoni
    TI__Genius 11525 points

    Hi Davide,

    I think a better solution would be to have a custom SCI bootloader reside in the Flash memory of the device and choose to boot from Flash (zero boot mode), also enabling JTAGLOCK so that no one can change the boot mode for the device.

    There are examples available in C2000Ware for SCI Flash Kernels, here is the accompanying application note: Serial Flash Programming of C2000 Microcontrollers

    Thanks and regards,

    Charles