• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 82 subscribers
  • Views 297 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMS320F280049C-Q1: questions about secure RAM

Kita Li
Intellectual 2725 points

Part Number: TMS320F280049C-Q1

Hi champs,

the customer has 2 questions about DCSM, could you give me some advices about that?

1. All LSRAMs can be secured on the device. But why the other RAM, such as M0/M1 RAM, GS0/1/2/3 RAM can't be secured?

2. What is the main purpose of encrypting RAM? Is it to prevent someone from reading the contents of RAM through JTAG?

Thanks!

Best Regards

Kita

  • 0
    TI__Mastermind 30185 points

    Hello Kita,

    Kita Li said:
    1. All LSRAMs can be secured on the device. But why the other RAM, such as M0/M1 RAM, GS0/1/2/3 RAM can't be secured?

    I believe this is because the Mx and GSx RAMs have different purposes than LSx RAMs. I will let a DCSM expert respond on this point.

    Kita Li said:
    2. What is the main purpose of encrypting RAM? Is it to prevent someone from reading the contents of RAM through JTAG?

    Likely, yes since that is the only way to read the memory on the device once it has been programmed. The JTAG pins, depending on the customer's application, could be exposed and used by someone else if they're available and in this case encrypting RAM would be useful.

  • +1 in reply to Omer Amir
    TI__Guru* 95315 points
    Kita Li said:
    1. All LSRAMs can be secured on the device. But why the other RAM, such as M0/M1 RAM, GS0/1/2/3 RAM can't be secured?

    This is done due to multiple reasons:

    1. We need some unsecure RAM to load code that would unsecure the device. This is useful when you want to update the Flash, for example.
    2. Some unsecure RAM is needed during production testing.
    3. Compatibility with earlier devices. M0/M1 has always been unsecure right from our very first 28xx device (TMS320F281x)).
    Kita Li said:
    2. What is the main purpose of encrypting RAM? Is it to prevent someone from reading the contents of RAM through JTAG?

    By "encrypting", I presume you are referring to "securing". Those are two completely different things. If your question pertains to securing, the answer is "yes".

  • 0 in reply to Hareesh Janakiraman
    TI__Intellectual 2725 points

    Hi Hareesh,

    May I ask one more question from customer? The customer consulted me that DCSM can only secure flash and RAM, but not OTP, so it is possible to change the OTP area without knowing the DCSM password. The customer wondered if it would be possible to load the code in the OTP area to change linkpointer and password, don't change the code in the secure region via JTAG. If this can be achieved, is there a risk?

    Thanks!

    Kita

  • +1 in reply to Kita Li
    TI__Guru* 95315 points

    Kita,

        The DCSM passwords are stored in the OTP and the OTP is secure as well. Otherwise, anyone can access the passwords.