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TMS320F280049C: Soft Reset, need persistent register

Eric Best
Expert 7505 points

Part Number: TMS320F280049C

I am looking for a register that is persistent through a warm reset.  Need a flag that can be passed from application back to bootloader on a soft reset. 

Ideally this should be a register, as using RAM is historically taboo.  Please advise.

-Eric

  • 0
    TI__Guru** 116081 points
    Eric,

    Are you looking for general purpose register ? What kind of flag or status you are looking for?

    Regards,

    Vivek Singh
  • 0 in reply to Vivek Singh
    TI__Expert 7505 points
    Hi Vivek,

    I'm looking for any peripheral register which is not affected by a warm reset. Likely 99% of registers will be reset to their default states (on a soft reset). This is needed so we can be executing in the application, receive a message to flash update via CAN, *set a flag*, force a SW reset, and in the reset handler, check this flag to see that we entered from the application through the SW reset. Classic app to bootloader swap.
    If RAM can be considered persistent through a SW reset, then we can simply use RAM. However, in the auto industry, this is not the preferred method unless we 100% confident in RAM contents will persist.
    -Eric
  • 0 in reply to Eric Best
    TI__Guru** 116081 points
    Eric,

    If you issuing soft reset via WD module then we have RESC register which does have status to tell if reset was cause by WD and this does not get reset by XRSn or WD reset. So you can use the this status bit.

    Regards,
    Vivek Singh
  • 0 in reply to Vivek Singh
    TI__Expert 7505 points
    Hi Vivek,

    Thanks for the quick reply. Ideally, we are looking for something that is distinguished from the reset cause. For example, there could be a need to treat a WD event differently from an Update_Flash event, or possibly from two different soft reset cases. This is definitely a portion of the reset handler (reset caused used to determine that it was indeed a Soft Reset). However, we need an additional user programmable flag for this use case. A single register should suffice (a handful of bits actually).

    Are 100% of the peripheral registers reset on this device when a Soft Reset occurs?

    Regards,
    Eric
  • 0 in reply to Eric Best
    TI__Guru** 116081 points

    Ok, but when you say soft reset, it's still WD reset. Right? I don't think we have any general purpose register like this but let me check and get back to you.

    Regards,
    Vivek Singh

  • 0 in reply to Vivek Singh
    TI__Expert 7505 points
    that is correct. Just need a single address that can be written to, issue a reset via SW (WD), and then read back from that address with persistent state.
  • 0 in reply to Eric Best
    TI__Expert 7505 points
    Hi Vivek,

    Please let me know if any update on locating a persistent register.

    Regards,
    Eric
  • 0 in reply to Eric Best
    TI__Guru** 116081 points
    Eric,

    We do not have a register which can be used for this purpose. You need to use the RAM. To avoid the risk, you could update the value in three separate register and do the voting logic in SW after reading all the three location.

    Regards,
    Vivek Singh