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C667x warm reset

Daisuke Maeda
Guru 20205 points

Can the POR pin and the RESETFULL pin be only used for the cold reset (Power-on reset)?
Can those pins not be used for the warm reset?

Best regards,

Daisuke

 

  • 0
    Guru 20205 points

    Our customer wants to perform the warm reset, that is performed when all power supplies are maintaining their nominal values.
    However, there is only the power-on reset circuit on their custom board. The POR pin and the RESETFULL pin are controlled at the same time by the host controller, and the RESETFULL pin has a delay of 1msec. The RESET pin is controlled by the power-good signal of 3.3V.

    Best regards,

    Daisuke

     

  • 0 in reply to Daisuke Maeda
    Guru 20205 points

    On the C6678EVM, the push button switch to assert the RESETFULL pin can be used, but the push button switch for the cold reset can not be used in current implementation.

    I guess the RESETFULL pin can be used for the warm reset and the POR pin must be held inactive (high) throughout this reset sequence.

    Is my guess correct?

    Best regards,

    Daisuke

     

  • 0 in reply to Daisuke Maeda
    Guru 20205 points

    Hi,

    Please give me an answer as soon as possible.
    Your prompt reply would be appreciated.

    Best regards,

    Daisuke

     

  • 0 in reply to Daisuke Maeda
    TI__Genius 12065 points

    Daisuke,

    There are Power-on Reset and Hard Reset (Warm Reset) sections in the C667x device data manual (such as section 7.4.1 and section 7.4.2 in C6678 data manual).

    POR is initiated by PORz and RESETFULLz pins. 

    But Hard Reset is initiated by the following external or internal triggers:

    • RESET pin
    • RSCTRL register in PLLCTL
    • Watchdog timer
    • Emulation

    RESETFULLz is not used for Hard Reset. And PORz pin should be held inactive (high) throughout the warm reset sequence as mentioned in the note.

    Do you see any statements in the data manual cause confusion for the POR and Hard Reset please? 

  • 0 in reply to Steven Ji
    Guru 20205 points

    Hi Steven,

    Thank you for your reply.

    The statements in data manual seem to cause a slight confusion for how to use the RESETFULL pin. In Figure 7-4, the RESETFULLz is asserted (driven low), it seems the warm reset.
    In addition, C6678EVM has the push button switch to assert the RESETFULLz, this switch can be used when all power supplies are maintaining their normal operating conditions.

    I understand that Power-on reset is initiated by PORz and RESETFULLz pins. But I have the question that is not cleared.
    My question is whether the power-up sequencing is required for Power-on reset. Can Power-on reset be performed when all power supplies are maintaining their normal operating conditions?

    Best regards,

    Daisuke

     

  • 0 in reply to Daisuke Maeda
    TI__Mastermind 42545 points

    Hi Daisuke,

    The PORz and the RESETFULLz can be cycled low to initiate a power-on reset even if the power supplies are maintained in their valid state. If you cycle PORz low then you must also cycle RESETFULLz low and follow the timing requirements between the two signals described in the power sequencing section of the data manual. RESETFULLz must go high after PORz to correctly latch the bootmode. 

    Remember that RESETFULLz will set the C6678 to it's default state like PORz. You can cycle RESETFULLz low to set the device to default while keeping PORz high but there is not restriction that you must keep PORz high.

    Regards, Bill

  • 0 in reply to Bill Taboada
    Guru 20205 points

    Hi Bill,

    Thank you for your reply.

    To initiate a power-on reset when the power supplies are maintained in their valid state, is the hold time for the PORz defined?
    Do the periods described in the power sequencing section of the data manual meet this hold time?

    Best regards,

    Daisuke

     

  • 0 in reply to Daisuke Maeda
    TI__Mastermind 42545 points

    Hi Daisuke,

    The timing in the power supply sequencing chapter is sufficient but it adds additional time to ensure that the power supplies have settled. If you are using the PORz after the power supplies have are present you must meet the following conditions. 

    1) RESETFULLz must go low with PORz.

    2) PORz must be low for at least 500*C where C is equal to the clock period of the CORECLK.

    3) RESETFULLz must be low for at least 24 * C after PORz goes high.

    Regards, Bill

  • 0 in reply to Bill Taboada
    Guru 20205 points

    Hi Bill,

    Thank you for your reply.

    Best regards,

    Daisuke