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[C5535] Wake-up pin Interrupt to cause external power management to re-enable power to DSP I/Os.

Kaka
Guru 24520 points

Hi community member,

Please let me confirm the TRM description.

I found the following explanation on RTC-only mode in TRM. 

> In addition, the RTC is able to output an alarm or periodic interrupt on the WAKEUP pin to cause external power management to re-enable power to the DSP core and I/O.

It seems that the Wakeup pin can use to re-enable the external power management IC. If customer system use the wakeup pin as Wake-up source from RTC-only mode, can this pin also use to re-enable external power management IC?

If yes, would you show us the schematics in order to use the Wake-up pin as wake-up interrupt and wake-up source for external power management IC?

If you have any question, please let me know.

Best regards.

Kaka

  • 0
    TI__Genius 12575 points

    Hi Kaka-san,

    Yes, in RTC ONLY mode  RTC is able to output an alarm or periodic interrupt on the WAKEUP pin to cause external power management to re-enable power to the DSP core and I/O.

    The WAKEUP pin is a bidirectional pin that can be used as an input to wake up the DSP clock domains or it can be used as an open-drain output to wake up an external device. At power-up the WAKEUP pin is configured as an input.

    With respect to schematics C5515 evm is probably best. Wake-up goes to a header with either pull up or pull down to use as input or output.

    Regards

     Vasanth

  • 0 in reply to Vasantha K
    Guru 24520 points

    Hi Vasanth,

    Thank you for your response.
    I referred to C5515EVM schematics, I understand as below.
    If would like to use the WAKEUP pin as bidirectional pin, need to mount the both resisters of the pull-up and the pull-down and switch them for use case .
    Because C5535 need to input the pulse from Wakeup pin in order to wake-up from RTC-only mode, and to enable external power, we need to keep the Wakeup pin output "high" to the enable signal to the external power IC.

    So, I think that we could not use this pin as bidirectional pin without controlling the switch for pull-up and pull-down.


    Best regards.
    Kaka