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TMS320C6678: Warm Reset, NMI and LRESET.

erez cohen
Intellectual 595 points

Part Number: TMS320C6678

Hello,

on my system no requirement to support for DSP Core Reset nor NMI.

In case functionality as described on DS table 7-46 (pins CORESEL[3..0], LRESET, NMI and LRESETNMIEN) is not required can i ignore those signals and only terminate it?

regarding the Warm Reset, according my understanding it is applicable for DSP core Reset. in case it is not supported on my application can i terminate the LRESET and not use it? are there additional functionality for the LRESET pin? same for LRESETNMIEN pin.

thanks,

Erez.

  • 0
    TI__Mastermind 42545 points

    Hi Erez,

    There are four resets that you must control for the C6678; PORz, RESETFULLz, RESET and LRESET.  LRESET is the local core reset and the least used reset provided.  If you are not using the core reset you should pull LRESETNMIEN high and pull LRESET high.  RESET is the labeled as a soft reset.  This is generally used as a software control reset and is described in section 7.5.3 of the data manual.  If you are not controlling the RESET signal it should also be pulled high.  The PORz and RESETFULLz reset signals must be used when the device is first powered and must follow the power sequencing defined in the data manual.  For unused reset pins such as LRESET and LRESETNMIEN I suggested you use external pull up resistors to ensure a valid off state at all times.  The same is true for RESET if it is not used.

    Regards, Bill

  • 0 in reply to Bill Taboada
    Intellectual 595 points

    Hi Bill,

    Thanks for your replay!

    any additional functionality for the CORESEL[3..0] but selecting the core to be Reset?

    while DSP SW upgrade need to take place followed by DSP reboot, what Reset type should be performed? Soft Reset?

    Regards,

    Erez.

  • 0 in reply to erez cohen
    TI__Mastermind 42545 points

    Hi Erez,

    The CORESEL pins are only used when using the LRESET input.  If you have the LRESETNMIEN pulled high than CORESEL has not function.

    Regards, Bill

  • 0 in reply to Bill Taboada
    Intellectual 595 points

    Hi Bill,

    According DS while LRESETNMIEN set to '1' all others CORESEL[0..3],LRESET and NMI are dont care.

    on my design those 7 pins are not used and not connected. can i left it open? it has internal PU/PD, isnt it?

    incase it is MUST be externally terminated, please confirm the below:

    RESETNMIEN PU

    CORSEL[0..3] PD

    NMI PU

    LRESET PU 

    Erez.

  • 0 in reply to erez cohen
    Intellectual 595 points

    Hi,

    can you confirm?

    Erez,

  • 0 in reply to erez cohen
    TI__Mastermind 42545 points

    Hi Erez,

    You don't need external pulls for all seven of the signals.  I always recommend external pulls for signals associated with reset for the part.  In this case the minimum would be a pull up on the LRESETNMIEN signal to ensure it will remain the high state.  Generally I would also pull up the LRESET signal externally as well but if LRESETNMIEN is pulled high this isn't really necessary.

    Regards, Bill