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TMS320C6678: Soft reset survive registers

Alberto Chessa
Mastermind 6670 points
Part Number: TMS320C6678

Tool/software:

Hi,

There is register that survive to the soft reset but have a well defined values after a POR and can be used to pass information to a customized second stage bootloader?

I  want ot software select between two application:

1. C6678 EMIF16 Boot: RBL hand over ot the custom second stage boot loader (SSBL)

2. SSBL check the register to choose between two application:

     if register is equal to the POR normal value, boot APP1

     if  register is equal to a special key value, boot APP2

The  APP1 can set the special register to the special key for APP2, then start a device soft reset that will relunch the RBL and then SSBL. The SSBL will launch APP2 instead of APP1

 

  • 0
    TI__Mastermind 47963 points

    Refer to Datasheet -->https://www.ti.com/lit/ds/symlink/tms320c6678.pdf 

    As discussed in Section 7.5.3 of the above datasheet, a soft reset behaves like a hard reset, except that the EMIF16 MMRs, DDR3 EMIF MMRs, and the PCIe MMRs' sticky bits, as well as external memory contents, are retained. POR should also remain de-asserted during this time. You may have to use one of these for your needs, if possible.

    Thanks.

  • +1
    Mastermind 6670 points

    I thanks for the suggestion, but I prefer to not assume anything about the memories and register that control other device (as EMIF, PCI  and so on).

    Anyway, I think I have found a solution: the PWRSTATECTL register, that survive soft reset and have 16 bits for general purpose usage (and I does not use any power-saving features).

    I already tried and it seems it does the work.