[SOLVED] Locking and Unlocking JTAG port on TI RM48 AJSM using J-link Base

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  • [SOLVED] Locking and Unlocking JTAG port on TI RM48 AJSM using J-link Base

    Hi,

    We are using the RM48L530 and RM44L520 devices in our project in IAR embedded workbench 8.11 using the Segger j-link base. We have a security requirement to secure the JTAG port and we wish to do so using the AJSM (Advanced Jtag Security Module) built into the TI processor. From what i see with all of the TI documentation is that when using their tools and Emulator, there are easy ways of doing the device locking and unlocking via the TI-CCS (Code Composer Studio) IDE. However, our development and production tooling uses the Segger J-link and we would like to keep using this if possible.

    Locking the RM48 JTAG port seems easy enough. After locking, only the AJSM TAP is available. Unlocking the device must be done by scanning a special unlock code into the AJSM via this TAP.

    Does Segger have a tool that can do this?

    I read a post on the TI forums where someone said they use similar devices (also RM48 and j-link) and they have to make a script using JlinkScript? What is this JLinkScript and where can i see documenation on it?

    Another question, how can i program specific adresses (0xF000 0000, 0xF004 0000) of the device flash using the Segger directly (not all are allowed via J-Flash)?

    Regards,
    Chris Smith

  • Hello Chris,

    Thank you for your inquiry.

    ChrisSmith wrote:

    Locking the RM48 JTAG port seems easy enough. After locking, only the AJSM TAP is available. Unlocking the device must be done by scanning a special unlock code into the AJSM via this TAP.

    Does Segger have a tool that can do this?
    Currently we do not offer a tool to use the AJSM automatically.


    ChrisSmith wrote:

    I read a post on the TI forums where someone said they use similar devices (also RM48 and j-link) and they have to make a script using JlinkScript? What is this JLinkScript and where can i see documenation on it?
    A JLinkScript is a script file that can hook into different stages of J-Link communication and expand or replace the default behaviour of J-Link.
    More information can be found in the J-Link user manual UM08001 in the J-Link install folder under Docs/Manuals.
    The referenced script from TI forum is not known to us and was most likely created by the user.

    Is the AJSM and unlocking of the RM48 device publicly documented? If that is the case we could look into creating such a JLinkScript for you. However reusability of it seems highly unlikely so NREs would apply.
    Would that be an option for you?
    If yes, could you open a support ticket regarding this topic? More information can be found in my signature.

    ChrisSmith wrote:

    Another question, how can i program specific adresses (0xF000 0000, 0xF004 0000) of the device flash using the Segger directly (not all are allowed via J-Flash)?
    You can use the J-Link Commander to read and write specific memory addresses. More information can be found in the J-Link user manual UM08001.

    Best regards,
    Nino
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